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Title:
WIRELESS POWER DELIVERY OVER MEDIUM RANGE DISTANCES USING MAGNETIC, AND COMMON AND DIFFERENTIAL MODE-ELECTRIC, NEAR-FIELD COUPLING
Document Type and Number:
WIPO Patent Application WO/2017/083670
Kind Code:
A1
Abstract:
Embodiments described herein may relate to a system, comprising a power source configured to provide a signal at an oscillation frequency; a transmitter coupled to the power source, wherein the transmitter comprises at least one transmit resonator; one or more receivers, wherein the at least one receive resonator is operable to be coupled to the transmit resonator via a wireless resonant coupling link; one or more loads, wherein each of the one or more loads is switchably coupled to one or more respective receive resonators. The system includes a controller configured to determine an operational state of the system, wherein the operational state comprises at least one of three coupling modes (common mode, differential mode, and inductive mode), and is configured to cause the transmitter to provide electrical power to each of the one or more loads via the wireless resonant coupling link according to the determined operational state.

Inventors:
ADOLF BRAIN JOHN (US)
DEVAUL RICHARD WAYNE (US)
Application Number:
PCT/US2016/061560
Publication Date:
May 18, 2017
Filing Date:
November 11, 2016
Export Citation:
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Assignee:
X DEV LLC (US)
International Classes:
H02J50/12; H02J5/00; H02J50/40
Domestic Patent References:
WO2013022114A12013-02-14
Foreign References:
US20140139034A12014-05-22
US20130134793A12013-05-30
US20130221915A12013-08-29
US20130002034A12013-01-03
US20110218014A12011-09-08
US20160099579A12016-04-07
US20140139034A12014-05-22
Other References:
See also references of EP 3375069A4
Attorney, Agent or Firm:
AMER, Alyaman, A. (US)
Download PDF:
Claims:
CLAIMS

We Claim: . A system comprising:

a power source configured to pro vide a .signal at an oscillation frequency ;

a transmitter coupled to the power source, wherein the transmitter comprises at least one transmit resonator, wherein the at least one transmit resonator comprises at least one of; a transmit inductor or at least one transmit capacitor,•■wherein, the at least one transmit capacitor is a feast a transmit common mode capacitor, wherein the transmi common mode capacitor comprises a transmitter conductor and a ground reference, wherein the at least one transmit resonator is configured to resonate at one or more transmitter resonance frequencies, wherein the one or more transmitter resonance frequencies comprise at least the oscillation frequency;

one or more receivers, wherein each receiver of the one or more receivers comprises at least one receive resonator, wherein the at least one receive resonator comprises at least one of; a receive inductor or at least one receive capacitor, wherein the at least one receive capacitor is at least a recei ve common mode capacitor, wherein the receive commo mode capacitor comprises a receiver conductor and the ground reference, wherein the at least one receive resonator is configured to resonate at one or more receiver resonance f equencies, wherei the one or more receiver resonance frequencies'- comprise at least one of the one or more transmitter resonance frequencies, and wherein the at least one receive resonator is operable to be coupled to the 'transmit resonator via a wireless resonant coupling link;

one or more loads, wherein each of the one or more loads is s itchabi coupled to one or more respective receive resonators; and

a controller configured to:

determine an operational state of the system, wherein the operational state comprises at least one of three coupling modes, wherein the three coupling modes are common mode, differentia! mode, and inductive mode,

cause the transmitter t provide electrical power to each of the one or more loads via the wireless resonant coupling link according to the determined operational state.

2. The system of claim I, wherein the common mode comprises providing the wireless resonant coupling link via the at least one transmit common mode capacitor and the at least one receive common mode capacitor.

3. The system of claim 1, wherein the transmitter further comprises at least one transmit differential mode capacitor formed between two differential mode conductors, wherei the one or more receivers comprise at least one receive differentia! mode capacitor formed betwee two differential mode conductors, and wherein the differential mode comprises providing the wireless resonant coupling link via the at least one transmit differential mode capacitor and the at least one receive differential mode capacitor,

4. The system of claim 1, wherein the transmitter farther comprises at least one transmit inductive mode inductor, wherein the one r more receivers comprise at least one receive inductive mode inductor, and wherein, the inductive mode comprises providing the wireless resonant coupling link via the at least one transmit inductive mode inductor and the at least one receive inductive mode inductor.

5. The system of claim I , wherein the system further comprises:

one or more bidirectional couplers, wherei each of the bidirectional couplers is coupled to the transmitter; and

one or more impedance matching networks, wherein each of the impedance matching networks is coupled to at least one of: the transmitter or at least one of the one or more receivers.

6. The system of claim 5, wherein the controller is further c nfigured to:

receive, via the one or more bidirectional couplers, information indicative of reflected signal from each of the one or more loads:

determine an impedance of each of the one or more loads based on the received information; in response to deteraaining the impedance of each of ike one o more loads, adjust at least one of the one or more impedance matching networks.

7, The system of claim 5, wherein the controller is further configured to:

.determine a . priority of at least one load of the one or more loads;

based on the determined priority, determine an amount of electrical power that the transmitter will provide to the at least one load;

in response to deienjiining the amount of electrical power that the transmitter will provide to the at least one load, adjust at least one of the one or more impedance matching networks.

8, The system of claim 5, wherein the controller is farther configured to:

determine an amo nt of electrical power that the transmitter will deliver to each of the One or more loads;

in response to determining the amount of electrical power that the transmitter will deliver to eac of the on or more loads, adjust at least one of the one or more impedance .matching 'circuits such that the system delivers the determined amount of electrical power to each of the on or more loads. . The system of claim 8, wherein the controller is further configured to:

in response to determining' the amount of electrical power "that the transmitter will deliver to each of the one or more loads, adjust at least the electrical power fat the transmitter deli vers to each of the one or more loads via each of the coupling modes of the determined operational state.

10. The system of claim 5 , wherei the controller is farther configured to:

determine an ideal amount of electrical power that the transmitter will provide to each of the one or more loads;

determine an actual amount of electrical power received at eac of the one or more loads; compare the ideal amount of electrical power to the actual araouat of electrical power received at each of the one or more loads; and

based at least on. the comparison, determine one or more parasitic loads in the system.

11. A method comprising:

determining art operational state of the system, wherein the operational state comprises at least one of three coupling modes, wherein the three coupling- modes are common mode, differential mode, and inductive mode;

causing a -source coupled to a. transmitter to provide a · si nal · at an oscillation frequency; in response to the signal, causing transmit resonator of the transmitter to resonate at the Oscillation frequency, wherein the transmit resonator comprises at least one of: a transmit inductor or at least one transmit capacitor, wherein the at least one transmit capacitor is at least a transmit common mode capacitor, wherein the transmit common mode capacitor comprises a transmitter conductor and a ground plane;

in response to the transmit resonator resonatin at the oscillation .frequency, causing at least one receive resonator of one or more receivers to resonate at the oscillation -frequency, wherein each receive resonator comprises at least one of: a receive inductor or at least one receive capacitor, wherein the at least one receive capacitor is at least a receive common mode capacitor, wherein the receive common mode capacitor comprises a receiver conductor and the gromid plane, wherein each one of one or more loads is associated with one or more receivers, wherein each of the one or more -loads is switchabty coupled to the respecti ve receive resonator of its associated receiver, and wherein each respective receive resonator is operable to be coupled to the transmit resonator v ia a wireless resonant coupling link;

causing the transmitter to transmit electrical power to each of the one or more loads via the wireless resonant coupling link according to the determined operational state.

32. The method of claim 11, wherein the common mode comprises providing the w ireless resonant coupling link via the at least one transmit common mode capacitor and the at least one receive common mode capacitor.

13. The method of claim 11, wherein the transmitter further comprises at least one transmit differential mode capacitor- formed between two transmit differential mode conductors, wherein the one or more receivers comprise at least one receive differential mode capacitor formed between tw receive differential mode conductors, and wherein the differential mode comprises providin the wireless resonant couplin link via the at least one transmit differential mode capacitor and the at least one receiver differential mode capacitor,

14. The method of claim 11, wherein the transmitte further comprises at least one -transmit inductive mode inductor, wherein the one or more receivers comprise at least one receive inductive mode inductor, and wherein the inductive mode comprises providing the wireless resonant coupling link via the at least one transmit inductive mode inductor and the at least one receive inductive mode Inductor.

15. Tile Method of claim 1 mrlher comprising:

determining an amount of electrical power that the transmitter will deliver to each of the one or more loads;

in response to determining the amount of electrical power that the transmitter will deliver to eac of the one or more loads, adjusting at least one of the on or more impedance matching networks such that the system deli vers the determined amount of electrical power t each of the one or more loads.

Description:
Wireless Power Delivery Over Medium Range Distances Using Magnetic,, and Commoti and Differential Mode-Electric, Near-Field Coupling

CROSS REFERENCE TO RELATED APPLICATIO

0O1 | The present application claims priority to U.S. Patent Application No. 14/940,762, tiled on November 13, 2015 and entitled "Wireless -Power Delivery Over Medium Range Distances Using Magnetic, and Common and Differential Mode-Electric, Near-Field Coupling," which is hereby incorporated by reference in its entirety.

BACKGROUND

| ' 0002| Unless otherwise indicated herein, the materials described in this section are not prior art to- the claims in this application and are not admitted to be prior art by inclusion in this section.

0 31 Electronic devices, such as mobile phones, laptops, and tablets, have become an integral part of daily life. Other machines, such as cars, which have conventionally used nonelectric power sources, are increasingly relying on electricit as a power source. As electronic devices are often mobile, it may not be feasible for devices to stay connected to a power ' source via wires. Thus, electronic devices may use batteries to supply electric power when a device is not coupled to a fixed power source,

|§0IMJ Current battery technology, however, often does not mee the charge capacity and/or discharge rate demands of electronic devices, which may limit, the range of moveable devices. Even, in cases where batteries meet the power demands of a give device, such a device usually must be coupled to a fixed charging source via wires: in orde to recharge its battery. Such wired charging mechanisms may limit the movement, and- thus the usability , of the device while it is being charged. Also, as the number of devices connected to a charging source increases, the number of wires in the proximity of an electrical outlet may increase, causing "cord clutter."

SUMMARY

|0005| Because of limitations in wired delivery of power, solutions for wireless power .delivery are desirable. Some example systems disclosed herein use resonating elements, such as inductors and capacitors, to generate and couple with resonating -magnetic and or electric fields. Such systems may include a resonating element in a transmitter, and a resonating element in one or more receivers. Further, such systems may use the resonating element in the transmitter to generate a resonating field, and may use the resonating element in a receiver to couple with the resonating field. As such, some example systems may allow for wireless power delivery from a transmitter to receiver via the resonating field.

[0006] In one aspect, a system may include a power source configured to provide a signal at an oscillation frequency, a transmitter coupled to the power source, where the transmitter includes at least one transmit resonator, where the at least one transmit resonator includes at least one of: a transmit inductor or at least one transmit capacitor, where at least one transmit capacitor is a transmitter common mode capacitor, where the transmit common mode capacitor includes a transmitter conductor and a ground reference, where the at least one transmit resonator is configured to resonate at one. or more transmitter resonance frequencies; and -where the one or more ..transmitter resonance frequencies include at least the oscillation frequency.

|ββ07| The system further includes one or more receivers, where each receiver of the one or more receivers includes at least one receive resonator, where the at least one receive resonator includes at least one of: a receive inductor or at least one receive capacitor, where the at least one receive capacitor is a receive common mode capacitor,, where the receive common mode capacitor includes a receiver conductor and die ground reference, where the at least one receive resonator is configured to resonate at one or more receiver resonance frequencies, where the one or more receiver resonance frequencies include at least one of the one or more transmitter resonance frequencies, and where the at least one receive resonator is operable to he coupled to the transmit resonator via a wireless resonant coupling link,

fOftOSJ The system further includes one or more toads, where each of the one or more loads is switchabiy coupled to one or more respective receive resonators; and a -controller configured to: determine an operational state of the system, where the operational state includes at least one of three coupling modes, where the three ' coupling modes are common mode, differential mode, and inductive mode. The controller is further configured to cause the transmitter to provide electrical power to..each of the one or more loads via the wireless resonant coupling link accordin to the determined operational state.

fft00 | In another aspect, a method is provided that includes determining an operational state of the system, where the operational state includes at least one of three couplin modes, where the three coupling modes are common mode, differential mode, and inductive- mode; causing source coupled to a transmitter to provide a signal at an oscillation frequency; in response to the signal, causing a transmit resonator of the transmitter to resonate at the oscillation frequency, where the ' transmit resonato includes at least one of: a transmit inductor or at least one transmi capacitor, where at least one transmit capacito is ' transmit common mode capacitor, wherein the transmit common mode capacitor includes a transmitter conductor and a ground plane; in response to the transmit resonator resonating at the oscillation frequency, causing at least one receive resonator of one or more receivers to resonate at the oscillation frequency, where each receive resonator includes at least one of: a receive inductor or at least one receive capacitor, where at least one receive capacitor is a receive common mode capacitor, where the receive common mode capacitor includes a receiver conductor and the ground plane, where each one of one or more loads is associated with one receiver, where each of the one or more loads is switchably coupled to the recei ve resonator of its associated receiver, and where each receive resonator is operable to be coupled to the transmit resonator via a wireless resonant coupling link; and causing the transmi tter to .transmit electrical power to each of the one or more loads via the wireless resonant coupling link according to the determined operational state,

BRIEF DESCRIPTION OF THE DRAWINGS

|O01O| Figure 1 is a frmctionai block diagram illustrating the components of a wireless power deli very system, according to an example embodiment.

|0O111 . Figure 2 is a functional block diagram illustrating an impedance matching circuit- coupled to a transmitter, according to an example embodiment

100121 Figu e 3 is a diagram illustrating a representation of a bidirectional coupler used in a mathematical derivation, according to an example embodiment

|00131 Figure 4A to 4B illustrate a simplified circuit diagram of inductive resonant coupling, according to an example embodiment

(M>1 | Figure 5 A to 5C illustrate a simplified circuit diagram of common mode capacitive resonant coupling, according to an example embodiment.

I0015J Figure 6A to 6B is a simplified circuit diagram illustrating differential mode capaciti ve resonant coupling, according to an example embodiment.

f 00161 Figure 7 illustrates a method of delivering electrical power from a transmitter to one or more toads, according to an example embodiment

|¼17| Figure 8 is a ta le illustrating modes of operation of a system, according to an example embodiment,

f§018| Figure A to B illustrate a TDMA wireless resonant coupling channel, according to an example embodiment.

|6β1 | Figure 10 is a functional block diagram illustrating a wireless power delivery system employing side-channel caminimicatioiis, according to an example embodiment.

|(ift20| Figure 11 illustrates a method for confirming that a power transfer link and a side- channel communication link are established with the same receiver, according to an example embodiment.

O021| -Figure 12 is a functional block diagram illustrating a wireless power delivery system employing multiplexed power transfer, according to an. example embodiment

|0022| Figure 13 illustrates -a phas shift of a chain of repeaters repeating a transmitter near field, according to an example embodiment.

Figur 14 illustrates a method of controlling, the phase shift: of near fields in a system, according to an example embodiment.

|(M)24J Figure 15 illustrates a implementation of a wireless power delivery system according to an example embodiment.

!#&¾5| Figure 16 is a flowchart illustrating method of using high-frequency test pulse to determine one or more properties of reflecting entities in a near-field region of an oscillating field of a transmitter, according to an example embodiment.

fiM 6| Figures 17, 18, 1 A, and 19B- are simplified illustrations of unmanned aerial vehicles, according to example embodiments. |β¾27| Figure 20 illustrates a method of resonant wireless power transfer using a mobile wireless power-delivery device, according to an example em odiajettt.

fft028| Figure 21 is a simplified block diagram of a mobile power-delivery device, in accordanee with aa example embodiment.

DETAILED DESCRIPTION

| O29] Exemplary methods and systems are described herein, it should be understood that the word "exemplar)-" is used herein to mean "serving as an example, instance, or illustration " Any embodiment or feature described herein as "exemplary" is not necessarily to be construed, as preferred or advantageous over other embodiments or features. The exemplary embodiments described herein are not meant to be limiting. It will be readily understood that certain aspects of the disclosed systems and methods can be arranged and combined in a wide variety of different configurations, all of which are contemplated herein.

}0θ3 β | Furthermore, the particular arrangements shown in the Figures should not be viewed as limiting, it should be understood thai other embodiments may include more or less of each element shown in a given Figure.. Further, some of the illustrated elements may be combined or omitted. Yet further, an exemplary embodiment may includ elements that are not illustrated in the Figures,

|O03]| Furthermore; the term "'capacitor' as used herein should be understood broadly as any system, including one or more elements, with a capaeitrve property. As such, the term "capacitor" may foe used to refer to a lumped eapaeitive element and/or to a distributed capacitive element. Similarly, the term "inductor'' as used herein should be understood broadly as any system, including one or more elements, with an inductive property. As sueh s the- term "inductor" ma be used to refer to lumped inductive element and/or to a distributed inducti ve element.

I. Overview

(003 j Wireless power transfer involves the transmission of electrical power from a powe source to a receiver without coupling the receiver to. the power source with solid conductors (e.g., wires). Some conventional wireless power delivery systems ma include a transmitter and a receiver that: are inductively coupled via an oscillating magnetic field. For instance,, a power signal from a power source may be delivered to a transrait-coil in a transmitter to create an oscillating magnetic field. This oscillating magnetic field passes through a receive- coil in a receiver and induces AC to flow in the receiver and to a load. The magnitude of couplin between the transmitter and the receiver can be represented by a coupling factor k,. a dimension] ess parameter representing the fraction of flux couplin the transmitter and the receiver, In order to establish efficient power transfer in such conventional systems, die coupling factor k must he maintained at a sufficiently high level. Accordingly, the receiver coil usually needs to be located in close proximity to, and precisely positioned relative to, the transmitter coil. In addition, large transmitter and receiver coils may be necessary in. order to ensure sufficient coupling and to achieve reasonabl efficient power transfer.

{0033| Systems, devices, and methods disclosed herein relate to wireless power delivery systems tha utilize resonant, coupling to transfer power efficiently from a transmitter to a receiver. Such systems and methods may have less stringent proximity -and or positional requirements as compared to conventional inductively-coupled wireless power systems. That is, systems and methods disclosed herein may provide efficient wireiess power transfer even when the coupling factor k is small Specifically, in accordance with example embodiments, power may be transferred between a resouantly-coupled transmitter and receiver via an oscillating field generated by the transmitter. The oscillating field ma include an oscillating magnetic field component and/or an oscillating electric field component.

}tMI34f In example systems, the transmitter may include a transmit-resonator and the receiver may include a receive-resonator, A resonator, such as the tr&nsmit-resonator or the receive-resonator can be characterized by one or more resonant frequencies, among other factors. In particular, a transmit-resonator and a corresponding .receive-resonator may be configured to resonate at a common resonant frequency. When resonating, the receive-resonator may produce an output signal oscillating at the resonant frequency. The output signal may then be rectified or otherwise converted to electrical power, which can be delivered to a load.

|0Θ35| An oscillating electric and/or magnetic field may be described by its resonant frequency. Such fields have a resonant wavelength λό = ~~, where c is the speed of light in the medium through which the field is transmitted. The region within approximately one resonant wavelength from the resonator may be termed the "near field;' The electric and/or magnetic field in the near field is predominantly non-radiative. Optionally, the near field ma be considered the field that is at or below distances shorter than the 3* λ, where λ is a wavelength of the transmitted signal. Further, a field strength of the near field decays very rapidl with distance. The region beyond approximately on Or a few resonant wavelengths from the resonator is known as the "far field." The far field is almost exclusively radiative (e.g., RF radiation), and can be described as the region beyond the 3* λ distance.

[0036] A resonator, such as the transmit-resOnaior and the reeeive-resonater, ma be characterized in terms of an intrinsic loss rate which is a metric of energy dissipated over resonant cycles. The ratio Q -™, defines a quality factor for the resonator expressed in terms of energy loss per cycle. A resonator that, dissipates a smalle amount of energy per cycle ge erally has a higher quality factor Q. A system with a high quality factor Q (e.g., above .100) may be considered to be highly resonant.

£0037| Resonant systems with hig -Q resonators may be operable to transfer power wit high efficiency, even in situations where there may be weak coupling between the transmit- resonator and reeeive-resonator. That is, systems with a. low coupling .factor &:( £., k— 0.1) may sa l transfer power with high efficienc by employing resonators with sufficiently high quality factor Q (e.g., Q > 100), because the power transfer efficiency is a function of the quality factor Q and the coupling factor k Accordingly, highly resonant systems may be operable to wireiessly transfer powe over a Song range. Furthermore, in some embodiments, resonant systems may achieve greater eft cieueies than systems employin wired power transfer.

£0038j As described abo e, to transfer power, txansmit-resonators and receive-resonators may be coupled via an oscillating magnetic field and/or an oscillating electric field. Accordingly, example embodiments may be operable using any one or more of three coupling modes at an given time: (t) inductive mode, (ii) differential capacitive mode, and (iii) common: capacitive mode,

|0 39| In inductive mode, at least one inductor of the transmit-resonator receives a signal from the power source and resonates to generate a magnetic field that oscillates at a resonant frequency e¼. In such a scenario, at least one inductor of the receive-resonator may oscillate n response to being in proximity to the magnetic field. In differential capacitive mode, each capacitor of the transmit-resonator and the rec rve-resonatQf develops capacitance between two conductors, in common capacitive mode, each capacitor of the transmit-resonator and the receive-resonator develops a capacitance between a first conductor and a ground or common conductor.* in common capacitive mode, the ground or common conductor may include an earth connection. In other words, the ground or common conductor may include an electrical connectio to the earth's potential. The electrical connection may be physical connection (e.g., usin a metal stake), or ma be a capacitive connection to the earth's potential. The transmitter may include a controller to determine whether and when to del iver power via inductive mode, differential capacitive mode, and/or common capacitive mode and to control various elements of the transmitter accordingly.

{§040] In resonant wireless power transfer, higher efficiencies may be achieved b dynamicall adjusting impedances (resistance and/or reactance) on the transmitting side and/or the receiving side. For instance, the transmitter may include an impedance matching network coupled to the transmit-resonator. The impedance matching network on the transmitting side may be controlled so as to continually or intermittently adjust th impedance of the transmitter and associated elements. Similarly, ' die · receiver may include an impedance matching network coupled to th receive-resonator. The impedance matching network on th receiving side may be controlle so as to continuall or intermittently adjust the impedance of the receiver and associated elements.

(06 1 J In an example embodiment, the controller may carry out operations io create a circuit model based on a iransmit-reeeive. circuit associated with the transmitter and the. receiver. Using this transmit-receive circuit, the coupling factor k can also be calculated. Because the impedance associated with the receiver can be calculated from the reflected power received via the bidirectional RF coupler, the only remaining unknown in the circui t model is the coupling factor k for the transmitter and the receiver. The circuit model determines a specific relationshi between the coupling factor k and the impedance of the receiver. By determining the coupling coefficient an optimally efficient condition for the power transfer may be calculated or otherwise determined. The impedaace(s) on the transmitting and/or receivin sides can be adjusted via. the respective impedance matching- networks so as to achieve and/or maintain the optimally efficient condition. I» particular, dynamic impedaiice. adjustment ma be employed as the coupling between the transmit-resonator and die receive-resonator changes when the orientation a»d spatial relationship between me recei ver and the transmitter changes.

jiMM2| In some wireless power delivery systems described herein, die ' - transmitter may be operable to transfer power to any of a plurality of receivers. As many devices may be positioned within range of the transmitter for wireless power transfer, the transmitter may be configured to distinguish legitimate receivers from illegitimate devices that are not intended recipients of power transfer. These illegitimate devices may otherwise act as parasitic loads by receiving power from die transmitter without permission. Thus, prior to transferring power to a respective receiver, the. transmitter may cany out an authentication process to authenticate the receiver. The authentication -process may be conducted,, at least in pari, over a wireless side-channel communication link that establishes a secondary channel between the transmitter and the receiver, separate from the resonant power link Alternatively or -additionally, the transmitter may employ time-division and/or .frequency-division multiplexing to transfer power to a plurality of legitimate receivers respectively,

|0(M3J In accordance with example embodiments, the .resonant wireless power deliver system may include one or more resonant repeaters configured to spatially extend the near-field region of the oscillating field. Such resonant repeaters may h passive, in the sens that they may be powered only by the near field in which the are positioned. A plurality of repeaters may be configured in a chain-like configuration (e.g., a "daisy-chain"), to extend th transmitter near field, such that each subsequent repeater in the chain resonantly repeats the near field of an earlier link i the resonant .repeater chain. The spacing between repeaters andVor between a transmitter and a repeater may be limited by decay of the near field from one repeater to the next. •Furthermore, a. maximum distance to which the transmitter near field may be extended may be limited due to an accumulated phase shift across chained repeaters.

|(MM4J in accordance with example embodiments, both the maximum repeater spacing limitation and the accumulated phase shift limitations may be overcome by including additional capabilities in the repeaters. First by using active repeaters mat .each include an independent power source, the active repeaters c n "inject" additional power into the repeated fields, and thereby mitigate deca of the near field that may otherwise oceur. Second, cumulative phase delay across a chain o array of repeaters may be suppressed or eliminated by including one or more phase adjustment elements in some or all of the repeaters. Additionally or alternatively, phase control may be introduced in repeaters b means of metamaterials. ' Furthermore, phase control of repeaters may be implemented such that the transmitter and active repeaters behave together as a collective metamaterial.

|0045J In accordance with example embodiments, a wireless power delivery system may utilize test signals to probe physical properties of system components -and/or wireless power transmission paths between system components. More particularly, a transmitter may include a signal generator, or the like, ' configured to transmit o broadcast one or more types of wireless signals across the region, in which, wireless power transfer may occur. Such signals may be reflected by one or more reflecting entities (e.g., receivers, repeaters, etc.), and their reflection may then be received by a test-signal receiver of the transmitter. By analyzing phase and amplitude information of transmitted signals and their reflections, the transmitter may thus determine electrical properties of a reflecting entity, as well as of the transmission path between the transmitter and the reflecting entity. Utilization of the test signal in such a manner ma provide diagnostic capabilities similar to that of a vector network analyzer (VNA), as applied to •a wireless power delivery- system.

{0046} to an example system, test signals can span a broad frequency range to provide a frequency sweep, in a manner like that of a VNA frequenc sweep. .Analysis of such a frequency sweep may then be performed to determine an impedance of one or mor recei vers, a number of repeaters between the transmitter and a given receiver, a relative location of the transmitter and the given receiver, -and a characteristic impedance of a wireless- transmission path, among other properties of the system. This information can be used, in turn, to enhance the accurac of power delivery, and to distinguish between legitimate receivers and possible unauthorized receivers and/or parasitic devices, in other instances, test signals can be generated as pulses or chirps, being more narrowband ' in frequency and or time, Atialysts : -of reflections of such pulse signals may then be used in ranging applications, for example. | β θ47| In $ome. scenarios, a device may need wireless power-delivery while the device is out of range of s fixed resonan wireless power source, in some cases, it may be impraciical or difficult to provide a fixed transmitter in a location where devices need to operate. Examples include field devices, such as mobile deiivery traMportaiion vehicles, remote communication equipment, and clusters of devices in remote locations where fixed power sources are not available.

{ ' 00481 In accordance with example embodiments, a system for resonant wireless power delivery may include a mobile node or device that is a hybrid tran&nttter/receiver (TX/RX) configured to move, travel, and/or "commute" to remote receivers and deliver power wireless!y, in an example system, a hybrid TX RX device can include a transmitter component (TX) having functionality of a transmitter., a receiver (RX) component having ' functionality' of a receiver, and a power store for storing power (e.g., a battery) for supply to receivers. The power store may also serve as a power supply for various functions of the hybrid TX/RX device including, but not limited to, mobility (commuting), communications, control, and processing. The TX/RX device may take the form of an autonomous unmanned vehicle, in such a scenario, the autonomous unmanned vehicle may be operable to towel between a fixed transmitters and one or more specified locations that ma be host to one or more remote receivers. I» the location of the one or more remote receivers, the TX component may be operable to wsrelessl transfer power from the power store to the one or more remote recei vers. White proximate to the location of the fixed transmitter, the RX component may be configured to receive power via wireless power transfer, and to use the recei ved power to at least partially replenish (e.g., refill and/or recharge) its power store.

II, Exampl S st ms and Operation

i ' 0649| An exampie system 100 for wireless transfer of power is shown in Figure 1. The system 100 may include various subsystems, elements, . nd components as described below. One or more subsystems may include a controller configured, to carry out one or more of a variety of operations, I» accordance with example embodiments, a controller amy include one or more processors, memory, and machine language instructions stored in the memory that when executed b the one or more processors cause the controller to carry one or more of its controlling functions or operations. A controller may also include one or more interfaces for device control, coinniidiications, etc.

00SO| In -further accordance with example embodiments, various functions and operations described below amy be defined as methods that may be carried within the system, where at least some aspects of the methods can be implemented based on functions and/or operatioas earned out by one or more controllers an d or one or more of processors. Other aspects of the methods may be carried out by other elements or components of the system, under control of one or another controller, in response to environmental factors, or in response to receivin or detecting a signal, for example.

| 0S1| In m example embodiment, a wireless power delivery system may include a power source configured to wirelessly deliver power to a load via a transmitter and a receiver. As- shown in Figure 1, system 100 may include a transmitter 102 and a receiver 108, both of which may be considered subsystems of system 100, and a controller 114. For the sake of brevity in Figure .1 and elsewhere herein, control function^ and operations are generally described a being carried out only by the controller 114. Thus, controller 1 14 may be viewed conceptually as a unified control function, it should be understood, however, that as subsystems of system IOC), the transmitter 102 and receiver 1 8 may each include its own controller, as described elsewhere herein. Alternatively or additionally, the controller 1 14 may include a distributed computing system. e.g., a mesh network.

{0052} As such, the various control functions and operations attributed to controller 1 14 may be implemented across one or more -controllers, such as ones included (but not shown) in transmitter 102 and receiver 108. For example, an operation described as being carried out by the transmitter could be done so under control of a controller in the transmitter. Similarly, an operation described as being carried out by the receiver could be done so under control of a controller in the receiver.

}ίΗϊ53| in addition to each of the transmitter 102 and receiver 108 possibl including its own controller, each of them may also include. nd/be constructed of various types of electrical components. For example, electrical components may include circuit elements such as inverters, varactors, amplifiers, rectifiers, transistors, switches, relays, capacitors, inductors, diodes, transmissio lines, resonant cavities, sad conductors. Furthermore, the electrical components may be arranged tn any viable electrical configiii¾tion, such as lumped or distributed.

fftOS4| Returning to Figure 100, the transmitter 102 of system 100 may include a traasrait-resonatof 106. The transnirt-resonator 106 may have a high Q value and may be configured to resonate at one or more resonant frequencies. Transmitter 102 may be coupled with power source 104, which may be configured to supply transmit-resonator 106 with a signal oscillating at one of the transmit-resonator resonant f equencies. In an example, the power source 104 m y include a power oscillator to generate the oseiilating signal, which may be oseiilating at one of ' the . transmit-resonator resonant f equencies. The power oscillator may be powered by a power signal received from an electrical outlet. For example, the electrical outlet may supply the power source 104 with an AC voltage o 120 V at a frequency of 60 Hz. In other examples, the power source may include a converter that may use a power from a power signal, which may have a low-frequency (i.e. 60/50 Bz) t to generate a carrier signal that has an Oscillation ' frequency of one of the ' ■traasmit-resoaant frequencies. The carrier signal may he modulated to catty the power signal and may thus he the oscillating signal supplied by the power source 104.

|0055| Furthermore, the resonant frequency that the signal may oscillate at. also called the system, resonant frequency, may be chosen by controller 1 14 of system 100. Transmit- resonator 1 6 may resonate, upon receiving the oscillating signal from source 104, and consequently, may generate a field oscillating at the system resonant frequency.

|O056| Receiver .108 may include a receive- resonator 1 12. The receive-resonator .1 .12 may have a high Q value and may also be configured to resonate at the system resonant frequency. The receiver 108 may also includ a load 1 ,10. Thus, if receive-resonator .12 is in th range of the oscillating field (i.e. the field penetrates receive-resonaior 112), resonator 1 3 may wirelessly couple with the oscillating field, thereby resonantly coupling with transmit-resonator 106. Receive-resonaior 112, while resonating, ma generate a signal that ma ' be delivered to the load 110. Note that in the implementation where the oscillating signal generated by the power source 104 is a modulated, carrier ' signal (generated by a con verter), the receiver 108 may include a filter network. The ' filter network may be used to isolate the power signal from the modulated carrier signal The power- signal (i.e. 50/60 Hz signal) may then.be delivered to the load 110.

|0Θ57] In example systems, there may be more than one receiver. This is described below in further detail,

0058J Wireless power delivery systems may include at least one impedance matching ' network configured to increase the efficiency of wireless power transfer. Figure 2 illustrates an impedance matching network in a system, according to an exemplary embodiment As illustrated in Figure 2, the impedance matching network 202 is coupled to the transmitter 204. Further, the impedance matching- .network 202 mm be in series, parallel, or i -any other configuration with the transanrt-resonator 2:54. in some- embodiments, an impedance -matching network 218 may additionally and/or alternatively be coupled to the receiver. Furthermore, the impedance matching networks 202 and 218 may each include any combination of L matching networks, pi networks, T networks, and/or multi-section matching networks.

(0059J in some embodiments, the system ma deliver a determined power to the load by configuring an impedance matching network to match determined impedance. Within examples, a controller of the system ma determine a power to deliver fro the transmitter to the load. The controller may use at least the reflected impedance, from th load to the transmitter . , to determine tlie impedance that the impedance matching network(s) may be configured to match. Accordingly, the system m deliver the determined power to the load when the impedance matching -network matches the determined impedance.

{ ' 0060 j More specifically, tire controller of the system may generate a model, such as a SPICE, model, of the sy stem to determine the impedance that the impedance matching network may match. Ihe model may include known values .such as the actual impedance of the load, which the ' controller- may receive from the receiver usin methods described herein. However, the controller may need to determine the actual power supplied to the load from the transmitter and th reflected impedance, from the load to the transmitter, in order to fully characterize the mode! of the system (e.g. to derive the coupling factor k). The controller may use the felly characterized mode! of the system to dynamically impedance match by precisely determining the impedance that the impedance matching circuit may match,

|006 ' 1| Therefore, the system may include a bidirectional coupler, which may be used to determme the actual power -supplied to the load from the transmitter and the reflected impedance from the load to the transmitter. The bidirectional coupler may be u ed in conjunction with a computer and/or a controller to precisely solve for an impedance of the load connected to it The bidirectional coupler may also be used, in conjunction with a computer and/or a controller, to precisely solve for the amount power leaving the power source. The value of the reflected impedance of a load and the amount power leaving the source may be used, to adjust the impedance matching network. Accordingly, the system may be configured to dynamically impedance match in a single step by using the bidirectional coupler to determine the actual power supplied by the source and the reflected impedance from the load to the -transmitter.

| 062| However, the value of the reflected impedance from the load may change due to different factors, such as a change in the coupling between a transmitter and a receiver. The coupling between a transmitter and a receiver may change due to various factors, such as a change in the distance between the transmitter and the receiver.

|(i063| For example, the receiver ma move during power ' transfer, which may change the coupling between the transmitter and the recei er. Such relative movement may change the reflected impedance of the load. Accordingly, as the reflected impedance from the load to the txansmitter changes, the cofttroikr ma be configured to continuously or iftterahttefttJy solve for the actual power delivered to the load and the reflected load impedance, in order to dynamically impedance match.

}0il64f Figure 3 illustrates a network representation of a system* including the bidirectional coupler 302 thai is coupled in cascade between a power source 304 aad a load 306, according to an exemplary -embodiment As illustrated in Figure 3, the bidirectional coupler may be coupled between the power source .at port 2 and the rest of the system (lumped into load 306) at port 8. Generally, there may he forward and reflected power waves at each port of the bidirectional coupler (ports I. 3, 4, and 5).

065| The forward aad reflected waves, and thus the power and impedance, at each port, may be precisely determined by fully charaeterteing the RF properties of the bidirectional coupler. For instance, mathematical relationship between the Incoming and outgoing waves on each of the bidirectional coupler 302's ports may be used to precisely calculate the power delivered to the load 306 aad the load 30 ' s reflected impedance back to the source 304. The mathematical relationship may use an S-parameter characterization of the bidirectional coupler 302 to relate between the incoming and outgoing waves on each of the bidirectional coupler 302 "s ports.

J0066| The bidirectional coupler 302 may operate by coupling forward power from port 1 to port 3. An attenuated forward power may be coupled to port 4 and sampled at measurement F WD port 6, Additionally, a ' small amount of forward power may also be coupled into port 5 and measured at REF port 7.

|0067| Likewise, reflected power is coupled from port 3 to port .1 , and an attenuated power may be coupled to port 5 and sampled at measurement REF port 7, Additionally, a small amount of reflected power may be coupled into port 4 and measured at FWD port 6, Despite these non~ idealities, of the forward power couplin to port 5 and the reflected power coupling to port 4, a computer and/or a. controller may precisely calculate the power delivered to the load 306 and the load 306' s reflected impedance,

J0068| The premeasured values of the mathematical relationship (A) ma include a 4x4 S-parameter matrix and the input reflection ' coefficient, an S-parameter, of power source 302.Fufth.er, the non-idealities in the operation of the bidirectional coupler may be accounted for by premeasorrag the 4x4 S-parameter matrix of the bidirectional couple 302, In some embodiments, the S-parameters may be premeasured using a sector network analyzer (VNA). The measured S-parameters may be stored in a lookup table that a controller of system 300 may have access to.

JiMi69| Further, as explained above, the bidirectional coupler 302 ma be used to periodically make real-time measurements of wa ves that may be used to solve for the power delivered to the toad 306 and the load 306's reflected impedance. Specifically, in order to precisely calculate the power delivered to the load 306 and the load 306's reflected impedance, ' both the absolute magnitude of the power signals at potts 6 and 7 may he measured alon with the phase of each signal wit respect to the other. FWD and REF may include any measurement device or circuitry capabl of measuring signals, e.g., an ammeter, a voltmeter, a spectrum analyzer, etc. Furthermore, FWD and REF may send information indicative of the respective measured 'Si nals to the controller of the system,

|0070] Furthermore, certain configurations of network 300 may simplify the S-parameter characterization of the bidirectional coupler 302, By design, FWD 308 and REF 310 may be impedance matched to the ^ transmission line that carries (fee signals to each port to prevent signals from reflecting when measure at each pott. For example, FWD port 308 and REF port 310 may be 50 Q terminated when a transmission line that has characteristic impedance (Z0) of 50 Q is used to earn,- the signal to eac h port

[0071] Accordingly, a controller of a wireless power delivery system may use a bidirectional coupler to solve for the reflected impedance of the load and the power delivered to the load. The system may use the solved for values in the model of the system to fully characterize the system. As such * at least the ' coupling factor k may be calculated. Further, the controller may use the model of the system to predict the amount of power that may be delivered to a load by adjusting the impedance that the impedance matching circuit may match.

f0G72j Further, the controller may periodically measure th reflected impedance of the load and the power delivered to the load, according to a predetermined time period, which may range from microseconds to tens of seconds in length. After each measurement, the controller may periodically adjust at least one impedance matching network of the system, in an example, a controller may measure the reflected impedance and ma accordingly adjust an impedance matching network every millisecond using the method described above. Other time intervals are possible. Alternati vely, the controller ma measure the reflected impedance of the load and the power delivered to the load continuously, in such a scenario, the controller ma continuously adjust an impedance matching network of the system to deli ver a determined power to t e load.

|(M)73J In some embodiments, the wireless power delivery system may include a plurality of receiv er s coupled to a single transmitter with a single bidirectional coupler. In such a scenario, each receiver may reflect a signal to the transmitter due to a possible impedance mismatch at each load coupled to each receiver. The controller may use the measured values to hilly characterize the system in order to determine an impedance that the impedance matching network may match,

|00?4| in some embodiments, a plurality of receivers- may be coupled to single bidirectional coupler. The bidirectional coupler may use time-division multiplexing (TDM) to send the reflected signal of each receiver to the measurement device during a given interval of time. The controller may then use the method described above to solve for the reflected impedance of each load coupled to each respective receiver.

j 75j The controller of the system ma adjust at least one impedance matching circuit based on the measured values. In an example embodiment, a system with a plurality of receivers may include a impedance matching network coupled to the transmitter and/or to each of the receivers. However, as the transmitter may receive different reflected impedances from each load, it may not be possible for the controller to adjust- the impedance matching network to ' simultaneously match the reflected impedance of each receiver and the impedance of the power source. Accordingly, in some embodiments, the controller may adjust at least one impedance matching network of the impedance matching networks coupled to each of the receivers. In other embodiments, the -controller ma adjust the impedance matching network, coupled to the transmitter, to match the reflected impedance of a selected receiver from the plurality of receivers. As such, die selected receiver, whose reflected impedance, was matched .at the impedance matching network, may proportionately receive mor power than the other receivers in the system. In some embodiments, wireless power delivery to the selected receiver may be more efficien than such power delivery to other receivers of the plurality -of .receivers.

|0076| In other examples, a system with a plurality of receivers may perform impedance matching according to time-division (TDM) and/or l¾quency-division (FDM) multiplexing. For instance, in a TDM scheme, each receiver may be -configured to ' couple to the transmitter with a single impedance matching -network during a specific time interval. The system may receive a reflected signal from a receiver dining the specific time interval that the receiver is coupled to the transmitter. In such a scenario, the controller may adjust the impedance matching network such that each receiver ma receive maximum power during the interval that the receiver is co upled to the tr ansmitter, in an example embodiment, each recei ver of the pl urality of recei vers may be assigned a respective time slot according to a receiver priority or a recei er order. The time slots may be equal in duration, but need not be equal For example, receivers with higher receiver priorit may be assigned, to longer time slots than those receivers with a lower receiver priority.

|0077] In a EDM scheme, each recei ver may be configured to couple to the transmitter with on a specific respective frequency. The system may receive a respective reflected signal from each receiver on the specific frequency that the receiver is coupled to the transmitter on. la such a scenario,, the controller may adjust the impedance 1 matching networfcis), which may be connected to the transmitter and/or to each of the receivers, such that each receiver may receive a determined amount of power.

[0078] In yet another example of a system with a pluralit of receivers, a controller may determine the power that each, receiver may receive simultaneously from the transmitter by adjusting the impedance matching network. Specifically, the impedance of the impedance matching network may determine, , at least in part, the amount of power that each receiver may receive. For example, each receiver may receive power based on at least a difference between the receiver's impedance and that of the impedance matching network. Accordingly, the controller may adjust the impedance matching network so as to increase or decrease an amount of power delivered to a respecti e receiver, based at least on the receiver's impedance.

|ββ79] A controlle may determine the amount of power tha each receiver may receive from the transmitter based on various parameters. In an example embodiment, each receiver may be associated with a respective priority such that higher priority receivers may receive more power during a single power distribution cycle than lower priority recei vers. In other examples, a current charging state of the receiver (if the receiver is coupled to a load that includes a battery), may determine the amount of power that a receiver may receive. That is, a receiver with a low battery level may receive higher priority than receiver with a full battery, it is understood thai the controller ma distribute power to each receive of the plurality of receivers based on a variety of other parameters.

[0080] Within examples, a. controller may receive information indicative of at least one parameter from a receiver when authenticating the receiver. As such, the controller may generate a dynamic priorit list based on the received information.. la an example embodiment, the dynamic priority list may be updated when a receiver connects or disconnects from a transmitter. Further, a controller ma store the received information and the corresponding dynamic priority lists either locaily or on a server. In other examples, a receiver may send a controller updated Information if a parameter of the receiver changes after the initial synchronization process, In oilier examples, a controller may period cally query a receiver, via a side-channel communication link, for example, to request information regarding the state of the receiver. As such, the controller may receive, via the sid channel, for example, information such as the current ch arging state of a battery of a receiver or the current power requirements of a receiver.

{ ' 00811 In yet other examples,, a system may include one or more impedance matching networks in each receiver of the plurality of receivers. A system may additionally or alternatively include impedance matching networks in the ' transmitter and at least one of the receivers. In such scenarios, a controller may be configured to adjust a plurality of impedance matching networks of the system such that eac receive may receive determined amount, o power from the transmitter,

{0082J Additionally of alternatively, the system may use the dynamic impedance matching ' method described above to detect a parasitic receiver. Specifically, a controller of the System ma use infoiination, such as nominal impedance, about authorized receivers to generate a circuit model of at least portion of the wireless power delivery system.- Additionally or alternatively, the controller may generate the circuit model based on an approximation, estimation, or other determination of a couplin condition between the transmitter and the receiver, which may be based on their relative locations;. Based on the circuit model, the controller may calculate an ideal power reception amount that it may receive from each receiver. Accordingly, the controller may compare the calculated ideal power recei ed and the actual power recei ved. If the ideal and actual powers recei ved are not equal within a specified margin of error, the controller may determine .that a parasitic de vice may be present in the system. For example, the controller -may- .determine ' that a parasitic device may be present in the system if the value of the calculated power received varies by mo e than 10% of the value of the actual power received. Additionall or alternatively, the controller may use other methods disclosed herein to identify parasitic recei vers.

A. Coupling Modes

|0 S3| A transmitter and a receiver of a wireless power delivery system may establish a wireless coupling resonant link, and thus become resonantly- coupled, via various coupling modes. Each coupling mode is associated with a type of resonator that may be included in a transmitter and/or a receiver. Accordingly, a system ma excite a type of resonator so as to provide a wireless resonant link via the associated coupling mode. Furthermore, the system may maintain multiple wireless resonant links of different coupling mode types at any given time. Within examples, a transmitter and a receiver of a system may include at least one of three resonator types. As such, the operational state of a system may utilize at least one of three resonant coupling modes,

{008 | Figure -4 A and Figure 4.B illustrate an inductive resonant coupling mode, the first coupling mode, according to an exemplary embodiment Eac of transmit-resonator 402 and receive-resonator 404 may include at least an inductor. Further, each resonator may be configured to resonate at least at the system resonant frequency of system 400. Transmit- resonator 402 may resonate upon receiving a. signal, from power source 406, that is oscillating at the system resonant frequency. Thus, transmit inductor 408 of transmit-resonator 402 may generate a magnetic field oscillating at the system resonant frequency. Receive-resonator 404 may couple wit the oscillating magnetic field if it is within proximit to the transmit-resonator 402. As a result, a wireless coupling resonant- link may be established. Coupled receive-resonator 404 may then resonate, and may therefore generate a signal that may be delivered to load 412.

|008SJ Additionally or alternatively, the system .may- include a transmitter and/or a receiver that include a capacitive resonator, which may he operable to couple the transmitter and die receiver. I an example embodiment, each of the transmitter capacitive resonator and the receiver capacitive resonator may include at least a capacitor. The transmit-resonator may ' resonate upon receiving, from me power .source, a signal oscillating at the system resonant frequency. As the transmit-resonator resonates, the capacitor of the transmit-resonator may generate an electric field oscillating at the system resonant frequency.. The recei ve-resonator, i in proximity to the- transmit-resonator, may couple with the oscillating electric field; thereby establishing a wireless coupling link between the transmitter and the receiver. As such, the receive-resonator may resonate, and may therefore, generate a signal that may he delivered to a load coupled to the receiver. In an example embodiment, a system may include at least one of two types of eapacitive resonators, each of which .may be associated with a respective coupling mode. The two. capacitive resonators differ in the configuration of their respective capacitors. The first capacitive resonator may include a common mode capacitor, which may support a capacitance between a single conductor- and ground. A. common mode. ' capacitive resonator may be operable to provide a wireless coupling Jink via a coupling mode termed common mode. The second capacitive resonator type may include a differential mode capacitor, which may support a capacitance between two conductors. A differential mode capacitive resonator may be operable to provide a wireless coupling link via a coupling mode termed differential mode.

f§087| Figure SA, Figure SB, and Figure 5C illustrate a system, in three representations, that includes a common mode capacitive resonator, according to an exemplary embodiment. Eac of transmlt-resonator 502 and receive-resonator 504 includes common mode capacitive resonator. As such, each resonator Includes a common mode capacitor that includes a conductor and ground reference 506. Ground reference 506 ma conduct current to complete the circuit of traiisnntter 508 and receiver 510. Further, transmitter 508 may be coupled with power source 12 that may be connected on one end to ground reference 506 and on the other end to at. least transmitter conductor 514, Optionally power source 512 .need not be connected to the ground reference 506. Transmit- resonator 502 ma resonate upon receiving, from power source 51 , a signal that is oscillating at the system resonant frequency. As the tnmsnnt-resonator 502 resonates, common mode capacitor 536 of the transmii-resonaior 502 may generate an electric field oscillating at the system resonant frequency. Receiver 510 ' tnay include load 518 that may be connected on one end to ground reference 506 and on the other end to receiver conductor 520. I w thin the near field of transmit-resonator 502, the receive-resonator 504 (which includes common mode capacitor 522) may couple with the oscillating electric field, thereby establishing a wireless resonant coupling, link. As such, receive-resonator 504 may resonate, and may generate a signal that may be delivered to the load.

Q088J in some embodiments, the ground reference of the common mode capacitors may be coffiiected to earth ground via a direct or a mdirect connection. For example, the ground reference may include the infrastructure of a building housing the wireless power system, which may mclude an indirect connection to earth ground. In other examples, the ground reference may include a conductive object connected to common mode capacitors. As such, the conductive object may provide a conductive return path in a circuit including a transmitter and/or a receiver, 00891 Figures 6A. and 6B illustrate a system 600, in two representations, which includes a differential mode capacitor, according to an exemplary ' embodiment Each of transmit- resonator 602 and receive-resooator 604 may include- at least one capacitor. Power source 606 may supply a signal oscillating at a system, resonance frequency to transmit-resonator 602, Traasmit-resonator 602 ma resonat upon receiving the signa from source 606. As transmit- resonator 602 resonates, transmitter differential mode capacitor 60S may generate an electric field oscillating <a the system resonant f equency, Receive-resonator 604, if in proximity to the transmit-resonator 602, may couple with the oscillating electric field. As such, , a wireless resonant coupling link may he established between the transmitter and the receiver. Furthermore, receiver differential mode capacitor 610 may resonate, and may therefore generate a signal that may b delivered to load 612 coupled to receiver 614.

|OO90| In example embodiments, a system may establish a wireless resonant coupling link between a transmitter and a. receiver according to one or more coupling modes that include a e&paeiiive resonant coupling mode and an inductive resonant coupling mode. A transmitter and a receiver may each include the resonators necessary to establish a wireless link in each of the coupling modes. Furthermore, -a wireless coupling link may be maintained between the transmitter and .the recei ver that utilizes different coupling modes simultaneously or individually. In some examples, the resonators may include a single circuit element/that may be configured to operate either as an inductor, a capacitor, or both. In art example, an element ma include coils shaped like pair of conduc tor plates, such thai the element may operate as an inductor and/or a capacitor. In other examples, a transmitter or receiver may include multiple resonators arranged in resonator bank. The resonator bank may include at least one resonator that may -include an inductor, and at least one resonator that may include a capacitor. Accordingly, the resonator bank may be configured to establish wireless resonant coupling links in capacitive. and inductive resonant, coupling modes,

|0091| Figure 7 illustrates flowchart showin method 700 that raa establish a wireless resonant coupling link between a transmitter and a receiver of a system, according to an exemplary embodiment. I some embodiments, method 700 may be carried out by a controller of a system.

00?2J Furthermore, as noted above, the functionality described in connection with the flowcharts described herein can he implemented as special-function and/or configured general* function hardware modules, portions of program code executed by one or more processors for achieving specific logical functions, detemim fions, and/or steps described in connection with the flowchart shown in Figur 7. For example the one or more processors may be part of controller 1 14, Where used, program code can be stored on any type of non-transitory -computer- readable medium, for example, such as a storage device including a disk or hard drive.

}0Θ93| in additi on, each block of the flowchart shown in Figure 7 may represent circuitry that is wired to perform the specific logical functions in the process. Unless specifically indicated, functions in the flowchart shown in Figure 7 may be executed out of order from that shown or discussed, including substantially concurrent execution of separately described functions, or even in reverse order in some examples, depending on the functionality involved, so long as the overall functionality of the described method is maintained.

|00 4| As shown by block 702, of Figure 7, method 700 may invol ve determining an operational state of a. system. The determined operational state may include at least one coupling mode. For example., the determined operational state may include any of the wireless coupling modes described herein. Within examples, the determined operational state may be determined by a controller of the system. As shown by block 704, method 700 further includes causing a power source that is coupled to a transmitter of a system to provide a signal ' at: an oscillation frequency. For example, the oscillation frequency may be one of the one or more resonant frequencies of the transmitter. In some embodiments, the oscillation frequency may be a frequency within a range of resonant frequencies of the transnut-resonatof.

{00951 Accordingly, as shown by block 706, a transmit-resona or may resonate at the oscillation frequency upon receiving the signal from the power source of the system. The oscillating transmit-resonator may generate a field oscillatin at the oscillatio frequency. In some embodiments, the transmit-resonator may generate a. field that may be oscillating at a frequency within a range of resonant frequencies of the receive-resonaior. As shown by block 708, if a receive-tesonaior is located wi thin the range of the oscillating field generated by the trans it-resonator, the receive-resonator may also resonate at the oscillation frequency. As a result, as shown by block 710, a wireless resonant coupling link may be established according to the determined operational state. Finally* method 700 may cause the transmitter to deliver electrical power to each of the one or more loads via the established wireless resonant couplmg link, as shown by block 712.

|β(ίΐΜ | Figure 8 illustrates different combinations of coupling modes that may form wireless resonant coupling link, according to an exemplary embodiment: In an. example embodiment, a system may include transmitter and a receiver both having three different types of resonator elements (e.g. an inductor, a common-mode capacitor, and a differential-mode capacitor). Accordingly, a wireless resonant coupling Sink between the transmitter and the receiver ma include various combinations of the three differen coupling modes. Accordingly, combinations 1 -7 each include supporting a wireless resonant coupli link via at least one coupling mode. Operational state S represents when the system is not operating or when the transmitter and receiver are not coupled via a wireless resonant coupling link. Within examples, tile various -combinations of coupling modes forming the wireless coupling link between the transmitter and the receiver may be determined and controlled by a controller, in other examples, user may -provide an input to the controller tha may direct the system to form a wireless resonant- coupling li nk with a gi ven combination of coupling modes.

Jy# 7 In an example embodiment, a system may establish wireless resonant coupling links between a transmitter and a plurality of receivers. In suc a scenario, th pluralit of receivers may all operate in a single operational state to establish simultaneous links to th transmitter. In other scenarios, each of the recei vers may establish a wireless resonant coupling link with the transmitter using different coupling mode. Transmitters of such systems may include a resonator bank configured to enable simultaneous links with a pl urality of receivers via one or more coupling modes.

098| As explained elsewhere herein, a system may employ time division multiple access (TDMA) to establish a wireless resonant coupling link that may be shared by a plurality of receivers. Specifically, the wireless resonant coupling : link may be divided into different time slots within a given time frame. As such, each recei ver of the plurality of receivers may receive electrical power from the transmitter during an assigned time slot within die given time frame. In other words, within the given time frame, the transmitter may distribute power to a given receiver during a given time slot. Each receive may be assigned to receive power during one or more time slots within the time frame.

} β θ9 | Figure 9A illustrates a TDM A wireless resonant coupling link, according to an exemplary embodiment. Specifically, the ten time slots (Tl-T 10 may represent a single time frame of power distribution. The same distribution .may be repeated in subsequent time slots ΤΠ-Τ20 and/or time frames (not shown). Furthermore, a controller of the system may assign each receiver of the system one or more time slots during which the receiver may receive power from the transmitter. In this example, receivers 1-4 are configured to receive power from the transmitter dining various time slots of this time frame, wherea recei ver 5 is not configured to receive power, fox such a scenario, a ' controller may assign receivers 1-4 specific time slots during which they may receive power from the transmitter. The power may be transferred to a receiver during a given time slot according to any of the modes of operation of a system. Within examples, the controller may determine the operational state (e.g., th coupling mode type(s)) of each receiver during each interval of time. In other examples, the operational state may be input by a user of the respective receiver.

f lOO] Figure 9B illustrates a TDMA wireless resonant coupling link, according to an exemplary embodiment Similar to the system illustrated in Figure 9A, the ten time slots (Tl-TlO) may represent a single frame of power ' distribution. However, as illustrated in Figure B, more than on receiver may receive powe ' imultaneously from the transmitter. Furthermore, each recei ver may receive power according to an of the modes of operation of the system, in .some examples, the receivers receiving power simultaneously may receive wer according to tire same mode of operation. In other examples, the receivers receiving power simultaneously may receive po wer according to different modes of operation.

niOl} in accordance with some .embodiments, the components (e.g., transmitter and receiver) of system may include circuit elements (shown as element 212 in Figure 2„ element 414 m Figure 4, element 524 in Figure 5, and .element ..616 in Figure 6), such as inductors, capacitors, transistors, inverters, amplifiers, rectifiers, varactors, relays, diodes, transmission lines, resonant cavities and switches, which may be arranged to facilitate switching between the different coupling modes of a system. For example, a system may switch between the different modes by having both a coil and one or two (or more) conductors in a combination of series-parallel connections. In other examples, a system may dynamically suppress or enhance a coupling mode by dynamically addin lumped element reactive components in series or parallel between the elements of the resonator of each mode.

f 00102] i some examples, the operational state of a system may be determined by a controller of the system. For example, a controller may deterinm the mode of the operation of the system based on data that it may receive from a receiver, such as the receiver's power demands, preferred operational state, and location. Alternatively or additionally, the controller may determine the operational state based on data that may be input by a user of the system. Furthermore, the operational state ma be determined based on the status- -of the system and or environmental conditions.

|00103] in some embodiments, a controller may switch the operational state i response to detecting a parasitic device (using methods described herein) that may be diverting power from legitimate receiver, in an example, a system may be operating in a state that utilizes common mode resonant coupling. However, controller ma detect a parasitic device that may also be coupled to the transmitter using common mode. In response, the controller may stop wireless power delivery via the common mode, and may enable wireless power delivery via ' a ' differential capacttive coupling mode, an inductive resonant coupling mode, or both. In other embodiments, a controller may us environmental conditions to determine the system's operational state. For example, a controller may recei ve information indicative of a presence of high ferrite content objects in the system's environment. Accordingly, the .controller may determine to operate in a mode that does not utilize inductive resonant coupling mode.

100104] A controller ma also determine an amount of electrical power that a system ma deli er to each load in the system. The controller ma also make a determination of how much electrical power to deliver to each load via each available coupling mode in the system. Accordingly, in an. example, the controller ma cause the power source to direct the ' determined amount of power to a resonator bank and further control the delivery of power to the respective receivers via the respective determined couplin modes.

|001Θ51 Furthermore, external .elements may be installed m a. system's environment, which may be configured to improve or otherwise modify the performance of the system. In some embodiments, field concentrators may be configured to shape an oscillating magnetic field (of an inductive resonator), an oscillating electric field (of a capacrtive resonator), or both. For example, high permeability materials, such as ferrites, may be installed in a. system's environment, i an example embodiment, while the system is operating in inductive resonant coupling mode, the high permeability material may he arranged so as to shape the oscillating magnetic field and extend its range. Similarly, high permittivity dielectric materials may be arranged in a system's environment. A capacitor of the system may utilize the high permittivity dielectric materials to increase or otherwise modify its capacitance, and hence adjust the properties of the electric field produced by a resonant capacitor. Furthermore, conductors ma also he arranged in a system's environment so as to affect the magnetic and/or the electric field produced by the system's resonators.

1061 Within examples, a system ma include circuit elements thai may be used as necessary i the system to implement the system's functionality. For example, a system may include circuit elements such as inverters, varaetors, amplifiers, .transmission. lines, resonant cavities rectifiers, transistors, switches, relays, capacitors, inductors, diodes, and conductors. A rela may be used for switching between circuit elements configured to operate each coupling mode. As. explained herein, a switch may connect a load to a receiver, such that the load is switchabiy coupled to the receive-tesonator. Other examples of possible uses for -various circuit elements are possible.

B, Power Transfer to Legitimate Receiver^)

f0010?| Figure 10 illustrates resonant wireless power delivery system 1000 according to an example embodiment The system 1000 includes a power source 1010, transmitter 1020, and a receiver HMO, The transmitter 1020 receives power from the power source 1010 and wire!essly transfers this power to the receiver 1040, The transmitter 1020 may be one of a plurality of transmitters. The receiver 1040 is one of a pluralit of receivers, that may receive power from the transmitter 1020.

{0010S| The transmitter 1020 includes a transmit-resonator 1022, and the receiver 1040 includes a receive-resonator 1 42. The transmit-resonator 1022 is supplied with a power signal from the power source 1010 oscillating at a resonant frequency &¾. As described above * the transmit-resonator 1022 resonates at the resonant frequency &½ and generates a field that oscillates at the resonant frequency The receiver-resonator 1042 is correspondingly configured to resonate at the resonant frequency ( , The receiver 1040 is placed in sufficient proximity to the transmitter 1020 to couple the receive-resonator 1042 with, the field generated b the transmit-resonator 1022, e.g., the receiver-resonator 1042 is within the field of the transmit-resonator 1022 depending for instance on the quality factor Q as described above. This coupling establishes a resonant power transfer link 1002 that provides a wireless conduit for power transfer between the transmit-resonator 1022 and the receive-resonator 1042, As also described above, the transmit-resonator .1022 and the receive-resonator 1042 may be coupled via an. oscillating magnetic field and/or an oscillating electric field. In particular, the coupling may include any one or more of the following three modes: (i) inductive mode, (it) differential capacitive mode, and (ill) common capacitive mode.

{§01091 While the receive-resonator 1042 resonates in response to the oscillating field, a rectifier 1048 or other power conversion circuit ma convert power from the receive- resonator 1042 and subsequentl deliver the power to a load 1060. While the load 1060 is incorporated into the receiver 1040 as illustrated in Figure 10, some embodiments may include loads that are physically separate or otherwise apart from the receiver 1040.

|0 110| As shown in Figure 10, the transmitter 1020 includes 'controller 1024. In an example embodiment, the controller 1024 ma determine what coupling mode(s) to employ and ma control various elements of the transmitter 1020 so a io establish and or maintain wireless resonant coupling links according to the determined coupling mode(s). The controller 1024 ma also determine the amount of power that is transferred via die respective coupling mode(s).

fOOl 111 A also described above, higher efficiencies can be achieved by adjusting impedances ' (resistance and or reactance) on the transmitting side and/or. the receiving side, e.g., impedance niaiehing. Accordingly, the transmitter 1020 may include an impedance matching network 1026 coupled to the transmit-resonator 1022. Similarly, the receive 1 40 may include an impedance matching network 1046 coupled to the receive- resonator 1042.

{001 12] in an example embodiment, a plurality of devices and objects may be present within a local erivirotanent of the transmitter 1020, In such a scenario, the example system 1000 may be configured to distinguish legitimate receivers from illegitimate devices that are no -inte ded recipients ' of power transfer. Without an ability to discriminate bet en possible recipients of power transfer, illegitimate devices .may act as parasitic, loads that may receive power from the transmitter without permission. Thus, prior to transferring power to the receiver 1040, the transmitter 1020 may carry out a -authentication process to authenticate the receiver 1040. in an example embodiment, the authentication process may be facilitated via a wireless side-channel communication link 1004.

|(ίβ1ΐ3| The transmitter 1020 may include a wireless communication interface 102 S and the receiver 1 40 ma include a corresponding wireless communication interface 1048, In such a scenario, the transmitter 1020 and the receiver 1040 may establish a side-channel communication link 1004 via a wireless -communication technology. For instance, classic BLUETOOTH® or BLUETOOTH® LOW ENERGY (BEE) (2.4 to 2.485 GHz UHF) or WIFl™ (2.4 GHz UHF/5 ' GHz SHE may be employed to provide secure communications between the transmitter 1020 and the recei ver 1040. Other wireless communication protocols are possible and contemplated. As shown in Figure 10, the side-channel link 1004 communicatively couples the transmitter 1020 and the receiver 1040 over a secondar channel that is separate from the resonant power transfer link 002. in alternative embodiments, however, the .transmitter 1020 and the receiver 1040 may emplo the same channel to transfer power and communicate information as described herein, e.g,, by modulating aspects of the power transfer to communicate the information.

|(M>114J In an example embodiment the transmitter 1020 can communicate with the receiver' 1030 over the side-channel communication link 1004 to determine that the receiver 1040 is authorized o otherwise permitted to receive power. The receiver 1040 may be configured to provide arty type of information and/or acknowledgement required b the transmitter 1020 to authenticate the receiver 1 40. For instance, the receiver 1040 may transmit an atitheaticatton. code, a message, or a key to the transmitter 1020, In such scenarios, a device without the ability to establish side-channel coramimications with the transmitter 1020 may not be identified as a legitimate device.

001151 The receiver 1040 may also include a controller 1044. As such, the controllers 1024, 1044 can conduct communications via the side-channel link 1004 and process the information exchanged between the transmitter 1020 and the receiver 1040.

|Ο01Ι6) As described above, when power is transferred from the transmitte 1020 to the receiver 1040, power may be reflected back to the transmitter 1020 As Figure- 10 illustrates, the transmitter 1020 may include a bi-directional F coupler 1030 to measure, the reflected, power as also described above. Using , measurements from the hi -directional RF coupler 1030, an optimal efficiency for the power transfer link .1002 may be ascertained, and the inipedaneefs) on the transmitting and/or receiving sides can he adjusted via the impedance matching networks .1026, 1046 so as to optimize or otherwise modify power delivery efficiency,

|ββ117| The impedance associated with the receiver 1.040 may be ' determined based on the reflected power detected by measurement devices in conjunction with the bidirectional RF coupler 030. if a nominal impedance (e.g., a designed impedance) of the .receiver 1 40 is known, a difference between the nominal ' impedance and the calculated impedance based on the measurement of reflected power ma indicate a presence of one or more parasitic loads. Such parasitic loads may include illegitimate receivers. Using the side-channel -communication link 1004 established between tire transmitter 1020 and the receiver 1040, the receiver 1040 may fee operable to communicate its nominal impedance to the transmitter 1020. Thus, the calculation of impedance using the bi-directional RF coupler 1030 may enable the identification of parasitic loads as -well as enable dynamic impedance matching as disclosed elsewhere herein. The impedance(s) of the transmitter 1020 and/or die recei ver 1040 can be adjusted via the impedance matching networks 1026, 1046 to account for the parasi tic loads.

fOOliS} As described herein, the . transmitter 1020 may be operable to identify the existence of the legitimate receiver 1040 through authentication communications- vi the side- channel eommimicatton link 1004. Additionally or alternatively, the transmitter 1020 may be operable to distinguish the legitimate reeeiver 1040 from other legitimate or illegitimate devices by other methods, in particular, the transmitter 1020 may be operable to control the o er transfer link 1002 and the communication over the skte-ehaaael communication link 1004 with the same recei ver 1040,

001191 Figure 11 illustrates an example method 1100 for confirming that the power transfer link 1002 and the side-channel communicatioii link 1004 are established with the same receiver 1040, In step 1 102, the transmitter 1020 and the receiver 1 40 m establish wireless communications via the side-channel communication link. 1004. in step 1 104, the receiver 1040 sends authentication information to the transmitter 1020 via side-channel communication link 1004, and in step 1.106, the transmitter 1020 evaluates the authentication information to determine that the receiver 1040 is permitted to receive power,

(00120J Having identified the existence of the legitimate receiver 1040 via the side-channel communicati n link 004, the transmitter 1020 ma atiempt to deteonme that the corresponding power transfer link 1002 is occu ng with th same receiver 1040, Accordingly, in step 1 108, the transmitter 1020 attempts to send a predetermined amount of power to the receiver 1040 via the power transfer link 1002. In- step 1 110, the transmitter 3020 communicates with the receiver 1040 via the side-channel communication link 100 to confirm that the receiver 1040 recei ved the power transmission from step 1108. For instance, the receiver 1040 can detect and report the power recei ved, if the recei ver 1040 Mis to provide information, confirming the power ' transmission from the transmitter 1020, the transmitter 1020 in step 1112 can re-attempt to establish the power transfer Sink 1002 with the receiver 1040. With each re-attempt, the transmitter 1 20 ca change the amount of power and/or modulate an impedance in an attempt to -account for an parasitic loads that, may be interfering with the power transfer to the correct receiver 1040. Additionally or alternatively, the transmitter 1020 can change the coupling iBode(s) for the powe transfer link. Once the power transfer link 1002 to the correct receiver 1040 is established, the transmitter 1020 cast further modulate impedance, if necessary, and continue to transfer power to the receiver 1040.

001211 view of the foregoing, the side-channel communication link 1004 may be employed to identity and authenticate the receiver 1040 arid to establish and adjust aspects of the power transfer link 1002, particularly to. account for parasitic loads. Specifically, fee side- channel communication link 1004 and the power transfer link 1002 may enable a variety of authentication, protocols so as to provide secure communications and power delivery. For example, the transmitter 1020 and receiver 1040 may be operable to .conduct -a password authentication- protocol (PAP), a challenge-handshake authentication protocol (CHAP), multi- factor authentication, or another type of cryptographic protocol. In general, however, the transmitter 1020 and the. receiver 1040 may employ the side-channel communication -fink 1,004 to exchange any -type of information to. manage any aspect of -the power transfer .link 1002.

00122] in an example embodiment, the system 1000 may help ensure the availability of the side-channel communication link 1004 by intermittently or continuously transmitting a certain amount of power via a predetermined wireless resonant coupling link configuration. This transmission 1006 can powe the wireless communication interface 1048 and allow it to remain active even if other aspects of the receiver 1040 do not receive power. As such, the receiver 1040 may receive sufficient power to establish initial communications with the transmitter 1020. Thereafter, the receiver 1040 may establish the power transfer link 1002. For instance, the transmission 1006 may provide a low power, .g. approximately .1 W, n such a scenario, the power distribution efficiency of the transmission 1006 is less of a concern at rel ati vely low powers .

{00123] As described above, the controller 1024 may determine what, -coupling mode to employ in the example system 1000, The controller 1024 may select coupling mode(s) based on the identification of parasitic loads. Fo instance, the transmitter 1020 may deliver power to lite receiver 1040 via a common capactti ve mode during a first time period. However, subsequent to the first time period, the controller 1024 may detect a parasitic device that may also be coupled to the transmitter 1020 via common eapacittve mode. Consequently, the controller 1024 may cause the transmitter 1020 and/or tire receiver 1040 to a switch to differential capaciti ve mode and/or inductive mode.

JWI24} As shown in Figure 12, the transmitter 1020 may also employ time- division and/or frequency-division nmilt.iplex.ing for the power transfer links 10O2a-d to a plurality of legitimate receivers I040a-d, respectively. Although Figure 12 may illustrate four receivers, it is understood that aay number of receivers may receive power from. a transmitter according to the present, disclosure.

1001251 Multiplexin may allo the transmitter 1020 to control how power is distributed to the receivers i0 0a-d. For example, with time-division multiplexing ' , power transfer during a given time period may be assigned to one or more specified receivers. With frequency-division multiplexing, power ma be transferred to specified receivers via respective frequencies. In such a scenario, the transmitter may be configured to transmit a plurality of the respective frequencies .simultaneously. Thus, as illustrated in Figure .12, the power transfer links ! 002a~d may occur at various designated time and/or frequency combinations (t, f);, (t fjs, ft fb, (t, f> , respectively. Accordingly, the use of multiplexing may promote coordinated delivery and availability of power to the receivers I040a-d.

1001261 Although, the transmitter 1020 may transfer power to one receiver via a single ' power transfer link having a particular time and/or frequency combination as shown in Figure 12, the transmitter 1020 in alternative embodiments may transfer power to one receiver via multiple power transfer links having different time and/or frequency combinations. Such an approach provides some redundancy in case tile transmitter .1020 is unable to transfer power with one or more of the power transfer links, e.g., due to interference from illegitimate .receivers). The transmitter 1020 can fall back OH the remaining power transfer links to transfer po wer to the receiver without interruption, in general, the transmitter 1020 can establish and selectively use any number of power · transfer links with single receiver, where the power transfer links use different respective time and/or frequenc combinations.

0 1271 The transmitter 1020 and the receivers I0 0a-d may employ side-channel communication links 1004a-d as described above to coordinate the multiplexed transfer of power. For instance, the transmitter 1020 .can communicate what time slots and/or which frequencies will be employed to transfer power to the receivers 1040a-d. in an example embodiment, wireless power deliver utilizing, time and frequency multiplexing may be more secure than osier- wireless power delivery methods' at least because the multiplexing schem employed by the transmitter 1020 is likely to be unknown to illegitimate devices, |β β 128| Without multiplexing, illegitimate devices with impedances or load profiles ' similar to legitimate devices might receive power without permission. hi eases where power resources may be limited, unpermitted use of such power resources might result in denial of power to legitimate receivers. Thus, multiplexing may allow more efficient and robust powe transfer from the transmitter to any number of legitimate receivers even in the presence of illegitimate or parasitic receivers.

£00129) It is understood that the use of a side-channel link is not limited to me examples -above- In an alternative .implementation, for instance* a -transmitter and a plurality of receivers may be pre-programme with information regarding the multiplexing scheme for power delivery to the plurality of receivers. Additionally or alternatively, the transmitter may be pre-programmed with information regarding the nominal impedances for the receivers, in some cases, the receivers may have the same impedance. A side-channel communication link can then be used to communicate information that is not pre-programmed into the transmitter and'or the receivers. For instance, if a wireless power delivery system is pre-programmed with the multiplexing scheme as well as information, relating to the nominal impedances for the recei vers, a side-channel communication link can be used by a. receiver to report the power received it has recei ved so that the existence of any parasitic loads can be determined as described above.

C« Repeaters

£00130) In accordance with exam le embodiments, the system may include one or more resonant repeaters (or simply repeaters) configured to spatially. extend the near field region of the oscillating field. Doing so may enlarge the region around the transmitter within ' which receivers may be laced in order to resonantly couple to, and receive power from, the oscillating field, as described above. In one example, a resonant repeater may include a repeat resonator configured to resonate at the resonant frequency ώο of the system (the system resonant frequency) when positioned in the transmitter near field. Driven by the resonating repeat resonator, the repeater may the repeat the transmitter near field, thereby extending the range of the near field. Such repeater may be passive, in the sense that they may be powered onl by the near field in which they are positioned,

|0013i I In an embodiment, a resonant repeater may receive a power signal via a wireless resonant coupling link that may ' have been established with the transmitter or with another repeater. As explained above, the wireless resonant coupling link may be established when the repeater couples with a first near field of the transmitter or of another repeater. The repeater ma then emit the signal via a second wireless coupling link established with another repeater and/or a receiver. Further, the signal that is emitted b the repeater has an associated near field, with which another repeater and/or a receiver may couple. In some embodiments, the repeater may emit a signal such that the near field associated with the -emitted signal is farther away from the transmitter than the extent of the first near field.

[00132) in farther accordance with example embodiments., a plurality of repeaters may be configured in a chain-like configuration, such that each subsequent repeater in the chain resonantl repeats the near field of an earlier link in the resonant repeater chain. The plurality of repeaters may also be configured in array-like configuration. In such scenarios, the transmitter near field may be continually -extended beyond its original range. Within examples, a repeater may establish several wireless coupling links with one. or more receivers and/or with one or more repeaters. In sotne. -embodiments,. repeater ma transmit power to one or more repeaters and/or to one or more receivers via a. singl wireless resonant coupling link.

[00133| Furthermore, each repeater may be configured to couple with a magnetic near field arid or an electric near field. Each repeater may also be configured to repeat a magnetic near field and/or an eleetric near field. A repeater may couple with * and may repeat, various field types depending at least on the operational state of the system. For example, each repeater may couple with a transmitter or another repeater usin at least one coupling mode, according to the operational state of the system. Accordingly, each repeater may include at least one of a common mode resonator, a differential mode resonator, and an inductive resonator. The on or more resonator types that may be included in a repeater may be collectively referred to as a repeat resonator,

f90134| While the transmitter near field can be extended using one or more repeaters, there may, however, be physical limitations to how far the near field ma be extended by chaining repeaters. Specifically, the near field will decay to some degree from one repeater to the next, so that each repeated field, produced by a passive repeater may have slightly lower, or substantially lower, average energy density than that produced by an earlier passive link. Thus, an. accumulated decay may eventually yield little or ao power transfer.

{001351 in accordance with example embodiments, the physical limitation due to deca of the near field may be overcome by including additional capabi lities in the repeaters. For example, each repeater may include an impedance matching circuit, that, may improve the power transfer efBciency from one repeater to another. In other examples, a system may mitigate decay of the near field by using active repeaters, each of which includes an independent (secondary) power source. As such, the active repeaters can "inject" additional power into the repeated .fields, la one example embodiment, all of the repeaters of the system -are active repeaters. In another example- embodiment,, only some of the repeaters are active repeaters, while others may be passive repeaters.

|60136J Within e m le , an active repeater may "inject" additional power into the repeated fields by applying a signal gain to the power signal that the active repeater receives from the transmitter or another repeater. The repeater may theft emit the signal to another repeater or a receiver. In some embodiments, a repealer may be configured to apply a predefined gain to the received signal. In other examples, a controller of the system may determine the gain thai each active repeater applies to the recei ved signal For example, a controller may direct lire active repeater to apply a gain that is equivalent to the propagation losses of the signal. Thus, a load may receive the signal that has ' the same magnitude as the original -signal provided by the primary power source. Furthermore, in such a scenario, the ex tent of each repeater near fie!d may be similar to the extent of the transmitter near field. In. other examples, an active repeater may be configured to emit a signal that may be larger in magnitud than the signal that was emitted by the transmitter.

j¾0137f Another physical limitation, discussed below, may arise due to accumulated phase delay across chained repealers. Also as discussed below, compensation for the effects of phase accumulation may be achieved by introducing adjustable phase shifts in repeaters, in accordance with example embodiments.

D. Metatiiateiials and Phase SMfi Adju tment

001381 Generally, a phase shift may occur between the near field that a repeater couples with and the near field that is repeated by the repeater. Specifically, the phase shift may occur due to a propagation delay of the power signal as the signal is recei ved and subsequently emitted by a repeater. Alternatively or additionally, the phase shift may occur, at least in part, due to propagation of the electromagnetic wave in a medium (e.g., air) between the transmitter and the repeater. Accordingly, each repeated near field produced by a given repeater will he shifted in oscillatory phase with respect to that produced by an earlier repeater. However, if the accumulated phase .shift across repeaters in a chain approaches one-quarter of the resonant wavelength, the transmitter and the chain of repeaters will appear to behave like a radiating antenna array, and thus radiate power as an electromagnetic wave in f¼r~r¾!d regio of the antenn array. Such radiative behavior ma result in overall power loss and inefficient power delivery.

f 00139 J Radiation loss due to cumulative phase delay across chain or an array of repeaters may be suppressed or eliminated by including one or more phase adjustment elements in s me or all of the repeaters. Specifically, a repeater having a phase adjustment -elem nt m y adjust the phase of its repeated near field. By appropriate phase adjustment, the near field of the system may be extended without becoming radiating antenna array. Phase adjustment may be provided in a repeater by lumped elements, such as inductors and capacitors, or by use of metaniaterials, or both. Additionally and/or alternatively, the phase may be adjusted by distributed elements that may have capaeitive and/or magnetic properties.

&ill 40] A repeater may include phase adjustment- elements that- ma be configured to adjust the phase of a magnetic and/or electric field. As explained above, a near field type may depend on the operational state of the system. For example, a system may operate using inductive resonant couplin and or capaeitive resonant coupling. As such, the near field that is produced b a transmitter, and which is then repeated by each repeater, may be a magnetic field (associated with inductive resonant coupling) and/or an electric field (associated with capaeitive resonant coupling). Within examples, the phase adjustment elements included i each repeater may include any circuit element operable to adjust the induced magnetic near field and/or the induced electric near field that is associated with each signal emitted by each repeater. For example, each repeater ma include lumped or distributed reactive components (i.e. capacitors and inductors) arranged to adj ust a phase o a received signal before and/or while repeating the signal.

O0141 in. some embodiments, the phase -adjustment elements of a repeater may be operable to shift the phase of a near field that the repeater may couple with. The repeater may subsequently regenerate the phase shifted nea field such that another repeater and/or a receiver may couple with the phase shifted near field More specifically, the repeater may shift the phase of the near field with respect to a. phase of fee near field at the respective location of the repeater. Alternatively, the repeater ma shirt the phase, of the near field that it couples with, with respect to a reference phase of the oscillating field generated by the transmit-resonator of the transmitter.

|00142] in accordance with some embodiments, a. repeater may include a metamaterial configured to couple with a near field, and to repeat the near field wit a finite phase shift. Generally, a metamaterial is a material that may have properties not found in nature, due to the fact that its properties depend on its structure rather than on the composition of its elements. As a non-limiting example, the metamaterial may include a split-ring resonator. In some embodiments, a metamaterial may be. configured to have a negative permeability, μ, ..and. a negative permittivity, ε. Such metamaterials may have a negative index of retraction, and thus may be referred to as negative index metamatenals (MM). The index of refraction of a niaieriai may be defined as the ratio of the speed of l ight to the phase velocity in a material.

| 0143] Therefore, -a field that is inciden on or that couples wit -an NIM .may- ' be refracted with a negative phase velocity. Accordingly, a NIM may be configured to adjust the phase of field oscillating at a resonant f equency to which it may couple. In some embodiments, ail of the repeaters of a system may include a NIM with negative permeability and permittivity at the resonant frequency . In other -embodiments, -some of the repeaters of a system may he NIM, while other repeaters may be repeaters that include lumped/distributed reactive components.

{00144} Within examples, NIM ma be configured such that the material may be adjustable so as to coattoliably shift the phase of a field (magnetic and/or electric) at least based on a- given resonant frequency. As explained herein, a repeater may couple with fields oscillating within a range of different frequencies, as the resonant frequency of the system may he adjusted .dynamically. Accordingly, the metaniaterial (NIM) repeater may be tunable so as to couple with, and shift the phase of, fields oscillating at different frequencies, in some ' embodiments, a metamaterial (NIM) repeater may be a active repeater, which may "inject" power into the repeated field with the shifted phase.

| 145| Within examples, each repeater may be configured to adjust the phase such that the near field of the emitted signal (i.e. repeated field) is in phase (or nearly so) with the near fieid produced by the earlier link in the array of repeaters. Accordingly, die phase of each repeated field m y be "locked" to the phase of the transmitter near field. I» such, a scenario, phase-locking m prevent the overall electrical length of the repeaters from approaching one- quarter of the resonant wavelength. Such a configuration of repeaters may be referred to as "phase locked" array of repeaters.

f 001461 However, shifting the phase of fields in a system may increase the overall reactive power In the system. The increase in the reactive power in the system ma result in an increase of power losses in the system.. Accordingly, in some embodiments, each repeater may be configured io adjust the phase of eac repeated field by a determined amount such that the reactive power is reduced, while keeping the overall electrical length of repeaters in an array shorter than one-quarter of the resonant wavelength. As such some repeaters need not be configured to shift the phase of their respective repeated field to avoid increasing the overall reactive power in the system, in some examples, the controller of a system may adjust the phase shifting elements of one or more repeaters in order to adjust the reacti ve power in the system. This adjustment of reactive power in a system may be viewed as similar or analogous to a power factor correction, which ma occur in conventional power transmission systems.

001 71 Figure 13 is a conceptual illustration of a relationship between a chain of repeaters and the phases of the respectively repeated near field at each repeater, according to an exemplary embodiment. By way of example, .a transmitter and a chain of five repeaters .(labeled Repeater 1 -5} are shown. For purposes of illustration, one full wavelength 1300 of a near field transmitted b transmitter as the resonant frequency of the system is shown. Also b way of example, the repeaters are placed at increments of 0.1 wavelength from tire transmitter, so that the last repeater in the chain as at one quarter wavelength from the transmitter. Wave i 300 is not teprese»fative of the amplitude of the transmitter field, as the transmitter field decays with distance. Rather, wave 1300 is mean to ilustrate a wavelength of the transmitter field oscillating at the resonant frequency of the system.

|0014S] Figure 13A illustrates a resonant transmitter near field, which is repeated by the repeaters 1-5 for the example case that includes no phase adjustment at the repeaters. As illustrated in magnified image 302 of Figure 13 A, each repeated field adds to the aggregat near field, and as such, the line representing die wave gets thicker as each repeater repeats the field that it couples with. Furthermore,, each repeated field is phase shifted with respect to the field that precedes it. Thus, the aggregate of the phase shifted fields, at the 5th repeater-approaches one quarter wavelength of the transmitter near field. Accordingly, and as -explained above, the aggregate of the transmitter field and each of the repeated fields of repeaters 1-5, may cause the transmitter and the chain of repeater to behave like a radiating antenna. Thus power may be radiated as an electromagnetic wave into a far-field region of the transmitter.

f 001 91 Figure ! 3B illustrates a resonant transmitter near field, which is repeated by the repeaters I -5 for the example case that now include phase adjustment at the repeaters. As Illustrated in Figure 1 3B, the phase of each repeated field is phase shifted, by it respective repeater, to match the phase of the transmitter near field. This may be a example of a "phase locked" array of repeaters described above. More significantly, and as illustrated in magnified image .1304 of Figure 1:3B, the aggregate of the phase shifted fields does not combine into a quarter wavelength of the transmitter near field. Thus, the transmitter and repeaters 1-5 may not behave like a radiating antenna. Accordingly, far field radiation may be suppressed or eliminated.

|0015OJ -Furthermore, both the passiv and active repeaters may incl de side channel commurticarion interfaces, described above, in order to communicate with other .components of the system, such as the transmitter, the receivers), and the repeaters. For example, an active repeater may recei ve instructions from a controller of the system, which may be located in the transmitter, to ' "inject" a specific amount of power into its repeated field. In an example, the controlle may make the determination for an active repeater to inject power based on information received from a receiver at the end of a repeater chain that includes the active repeater.

(M>i5i| Furthermore, an array of repeaters configured to control the phase of a field may behave as a sort of collective metamateriai. As explained above, a metamateriai is a material that ma have properties that are not found in nature. As the array of repeaters may control the phase shift in a way that is different from the natural phase shift that occurs while repeatkig and/or propagating a field, the array of repeaters may be considered as collective metarnaterial Snch an array of repeaters may be described as a metamateriai configured to suppress far field radiation by co&tro!ling the phase of the field with which the metamateriai couples,

100152] Accordingly, a chain o an arra of repeaters configured to control the phase of a near field may be modeled as a single metamateriai element/unit For example, the single metamateriai unit may couple with a transmitter near field at one end. O the other end, a receiver may couple with the phase shifted near field that is repeated by the single metamateriai. The phase shift of the repeated field ma be the aggregate of the phase shifts of the individual repeaters that make up die metamateriai. In another example, the metamateriat may be a "phase- locked" metamateriai , such that the phase of the near field that it repeats is identical to, or nearly identical to, a phase of the near field of the transmitter.

{§{>153| Figure 34 illustrates a flowchart showing a method J 400 that may adjust ' the phase of a signal from traHsmitter near field as it is repeated by one or more repeaters of a system, according to an exemplary embodiment in some embodiments, method 1400 may be carried out by a controller of a system.

f ©ft J 5 J As shown by block 1402, of Figure 14, method 1 00 ma involve causing a power source coupled to a transmitter to .provide a signal at an oscillation frequency. The oscillation frequency may be one of the one or more resonant frequencies of the transmit- resonator of the transmitter. As shown by block 1404, method 1400 further includes causing the transmitter,, in response to die signal from the source, to emit a transmitter signal associated with a transmitter near field region. Accordingly, as shown by bloek 1406, the method further includes causing at least one of the one or more repeaters to receive a respective first signal associated with a respective first near field region. Furthermore, the method includes causing each of the one or more repeaters to shift a phase of the respective firs signal by a specified amoun t The respective firs near field region of each repeater may be the transmitter near field, or may be a near field that had been repeated by a prior repeater.

|00155| The method 1400 may cause at least one of the one or more repeaters to emit a respective second signal associated with a second respective near field region, as shown by block 1410. An extent of the second respective aear field region may be configured to be farther away from the transmitter than the first respective near field. Block 1412 may include* causing at least one of one or more receivers to couple to at least one of the at least one final repeater. Accordingly, -a wireless resonant coupling link may be established between the each of the one or more receivers and at least one of the at least one final repeater. As such, block 141 may include causing the transmitter to transmit electrical power to each of the one or more loads via at least one. of the one or mor repeaters and the at least one of the one or mor receivers.

E, Dynamic Wireless Power Distribution System Probe

{(361561 Resonant wireless power transfer can be viewed as power transmission via one or more wireless .transmission, "paths" or "links." In addition to generating an oscillating field for wireless power transmission as described herein, the transmitter may also emit a "probe" signal in order to ascertain various properties of the wireless power transmission "paths" and entities ' that interact with the power transferred via the paths (e.g., receivers, repeaters, etc.). Such a probe can be used as a tool for dynamic diagnosis and analysis of electrical, "circuit" properties of a wireless power distribution system.

| 01S7| Thus, in accordance ' with example embodiments, a transmitter may include a signal generator, or the like, configured to ' transmit one or more types of wireless signals in order to determine one or more electromagnetic properties of propagation paths in th region in which wireless powe transfer may occur, and to further help distinguish, and/or disambiguate between legitimate receivers and possible unauthorized devices and/or parasitic loads. More specific ally, the signal generator ma generate test signals that span a. broad frequency range to provide a frequency sweep, hi a manner like that of a vector network analyzer (VNA) frequency sweep. By analyzing phase and amplitude inf rnia ion-of transmitted signals and their reflections, the transmitter may thus determine electrical properties of a reflecting entity, as well as of the transmission path between the transmitter and the reflecting entity.

| i581 la .furtker accordance ith example embodiments, the transmitter may include a test-signal receiver component configured to receive and measure retlections of transmitted test signals. A controller associated with the transmitter may then determine one or ' indi ' - electromagnetic properties of a reflectin entity by comparing the transmitted test signals with their corresponding reflections. By analyzing reflections of transmitted test signals, electromagnetic properties of various propagatio paths, including tire presence of, and electrical distances to, reflecting entities, and electromagnetic properties of those reflecting entities, may be ascertained. In practice, electrical distance can. ' be -measured in terms phase shift or delay of a reflected signal with respect to a transmitted (reference) signal. With this information, power delivery to legitimate devices can be optimized, and illegitimate power consumption can be identified and suppressed. Measurements and analyses can be carried out continuously, periodically, or episodically.

|001 ' 59| Test signals can carry both amplitude and phase information, i further accordance with example embodiments, both types of information can be analyzed to determine properties of a reflecting entit and of the propagation path between the transmitter and the reflecting entity, in an example application, test signals may be generated as continuous waves of one or- more frequencies, such one or more continuous sinusoids. In particular, by varying the frequency of a sinusoid (or other form or continuous wave) with time, either continuously or in a stepwise fashion, a test signal can he generated that sweeps across frequencies. For a typical application, the frequency may be varied linearly with time such that the frequency sweep resembles a ramp (or staircase) in frequency with time. Such a sweep can he repeated itom time t time, for example. The reflections of a sweep signal can be measured by the test-signal receiver and analyzed in a manner similar to a frequency sweep carried out with vector network- analyzer. For example, the reflected swee signal may display frequency-dependent phase delays corresponding to -electrical distance to a reflectin entity, as well phase delays resulting from frequency-dependent interactions with th reflecting- entity

{Q016ft} i n alternative example application, test signals can he time-pulse modulated. With this arrangement, reflections may correspond to individually reflected pulses. Again, reflected signals may be measured by the test-signal receiver. Measurement of pulsed signals and their reflections ' may be used for time-of-ftight .analyses .aad/or other rangiag techniques. Single frequency continuous wave test signals, frequency sweep test signals, and pulsed test signals are aon-lirniting examples of the types of test sigaals that can be used to probe electrical properti es of a wireless power transmission region of a transmitter

001611 Electromagnetic propert ies determined by analysis of test signals and their reflections can include impedance and admittance, for example. Reflecting entities can include receivers (both legitimate and unauthorised), repeaters, parasitic loads, and other that can interact electrically with an electric and/or magnetic field. In an example embodiment, -an. analysis of phase and amplitude information fro test poises and their respective reflections may be used to determine electrical "locations" of sources of impedance. For example, frequency -dependent characteristics of reflections and measured phase delays can be used to map out electrical properties along a propagation, path. This can be viewed as analogous to how a VNA may locate stubs,. taps, or shorts along a transmission path, in the context of wireless power delivery via an oscillating field, test signals can prov ide a sort of virtual "circuit diagram" of enti ties as mapped, out in the wireles power delivery region.

|00162J I accordance with example embodiments. She virtual circuit diagram provided by a frequency sweep can be used in the virtual circuit model of the system to enhance ' the accuracy of the model and to help identify legitimate receivers. As an example, by virtue of detected reflections, repeaters may appear as "hops" along propagation paths. Phase delays can then be used to ascertain locations of repeaters m terms of electrical distances to discontinuities in path impedances, for example. I» an example embodiment, mapping the system with one or more frequency sweeps can be ' carried ' oat as part of the system initialization and repeated from time to time to update the map. The initial map can then be used to associate circuit locations with respective receivers as they make their presence known (e.g., authenticating, requesting power, etc.),

1001633 In an example system, analysis of phase delay and amplitude from frequency sweep can be used to measure the impedance and coupling constant of a receiver. This information can also be input to a virtual circuit model of the system to improve the accuracy of the deduced coupling constant at the operational resonant frequency of power transfer, arid thereby further optimize power transfer.

fft0i 64| i further accordance with example embodiments, a frequency sweep test signal and its reflection from a receiver can be used to determine a cumber of repeater hops to the receiver. This can in turn be used to distinguish between- a legitimate receiver known to be a ceitaia number of receiver hops awa from the transmitter and an otherwise apparently similar unauthorized receiver determined to be a different number of hops away. For example, if analysis of a frequency sweep indicates the presence of more than one receiver having the same (or nearly the same) impedance, these receivers .may still be disambiguated by the respective - number of repeater hops to each respective receiver, as also determined from analysis of test signal s and infl ec tions. A rec eiv er determined to be a t an unrecognized number of hops away can thus be considered an unauthorized receiver, in which case the transmitter may take actions to prevent power transfer, as- described above.

|(i0165| in accordance wi th example embodiments, the controller of the transmitter can carry out the analysis of transmitted and reflected test signals, including continuous- wave signals, frequency sweep signals, and time-pulse modulates.! signals, among others. In particular, the controller can control a signal generator to cause a spec i fied type of test signal or signals. The controller can also control a test-signal receiver configured to detect one or more -reflections and correlate them with corresponding transmitted test signals. The controller can also perform one or more analyses of the transmitted and reflected signals to determine the various properties and results described above.

[ ' 00366) Within examples, the controller ma use test signals described herein to optimize or otherwise adjust wireless power transfer as elements are added to or removed from the system. In some embodiments, -a system may incorporate portable and/or non-stationary repeaters to extend th range of a transmitter. For example, a portable repeater may be added ' nto the system in order to increase the range of a transmitter i a specific direction. After an authentication process described herein, the controlle ma probe the environment of the system using a frequency swee or other form of test signal in order to determine on or more electromagnetic properties of the added propagation path . fO0J67| Furthermore, as explained above, a repeater may include phase elements, which may be adjustable. After determining the properties of the propagation path that may include the repeater, the controller may accordingly send instructions to the repeater that direct its operation. Within examples, the controller may adjust the phase adjusting elements of the repeater. In other examples, if the repeater h an active repeater, the controller may also determine the amount of power that the repeater may want to inject into its repeated field.

}0O168| Operations relating to use test signals described above may be implemented as a method by one or more processors of transmitter. Irs particular, the transmitter can include a transmit-resonator that is configured to couple power from a power Source into an oscillating field generated by the transmit-resonator resonating at a resonant frequency. As discussed above, the oscillating field cm be an oscillating electric field, an oscillating magnetic field, or both. An example method 1600 is illustrated in the form of a flowchart in Figure 1.6.

|(iOI69| At ste 1602, a signal generator of the transmitter transmits one or more ekctiomagne ic test signals at one or more frequencies. In accordance with example embodiments, the transmitted test signal will carry both phase and amplitude information.

|00170| At step 1604, a test-signal receiver of the transmitter receives a reflection of an given one of the transmitted test signals from one or more reflecting entities. By way of example, a reflecting entity could be a repeater or a receiver. Like the given transmitte test signal, the reflection will carry both phase and amplitude information.

|0017.l| At step .1606, a processor of the transmitter determines one or more electromagnetic properties of a reflecting entity based on an analysts the given transmitted test signal and a corresponding reflection. I particular, phas and amplitud information of the gi ven transmitted test signal and its corresponding reflectio can be analysed in a system of equations to determine such properties as impedance of the reflecting entity and/or characteristic impedance of a propagation path followed by the given transmitted test signal and its reflection.

1001721 It should be understood that steps or blocks of method 1600 as described herein are for purposes of example only. As such, those skilled in the art will appreciat that other arrangements and other elements (e.g. machines, interfaces, functions, orders, and groupings of functions, etc.) can be used instead, . . and some elements may be omitted, altogether according to fee desired results . Further, many of the elements that are described are functional entities that may be implemented as discrete of distributed components or in conjunction with other components, in any suitable combination and location.

¥, Example Applications

|O01?31 The example wireless power delivery systems described herein may be operable to provide power to the any number of devices, systems, and/or elements of an "Internet of Things." The Internet of Things may include any number or combination of devices in a variety of configurations and/or arrangem nts, in particular, one o more transmitters arid optionally one or mor repeaters may be spatiall organized to provide resonant oscillating fields withi a given region, zone, area, volume. Or other spatial bound. Other devices acting as receivers may each include receive-resonators so that they may be operably coupled to these resonant oscillating fields whe located within the spatial bound, hi such a scenario, each device may operably receive power via the resonant oscillating fields and may provide the power to one or more loads,

1001741 An example implementatio may provide a household wireles power delivery system. For example, appliances and other eiectricaliy-powered household devices may be configured to receive power from transmitters and repeater located throughout the household.

f ' 00175| In such a scenario, the wireiess power deliver system may increase the convenience ' of using electrically-powered devices. As an example, the use of the devices need not be limited to locations in the household near where wired power is accessible (e.g., wall outlets). In addition, the household may be dynamicall reconfigured because devices with different functions can be easily relocated in the household space without requiring new wired power connections.

f90176f in some embodiments, a greater number of electricaliy-powered devices may be powered in the household at least because deliver of wireiess power need not depend, on a fixed number of physical connections- to wall outlets, power strips, or extension cords. Rather, the wireless power delivery system may be configured to provide power to a large numbe of devices (e.g. hundreds or thousands of devices, or more). Furthermore, the wireless power ' delivery system ma be configured to raore-easiiy accommodate upgrades, in contrast to adding wall outlets aid installing electrical conduit in the household, an upgrade to a wireless power delivery system -may include an-oyer-the-air software update. la such a scenario, the software update may enable the wireless power delivery system to provide wireless powe to a larger number of devices by improved time-domain multiplexing. Other upgrade -types, functions, and or purposes are possible.

|0 177] Wireless power deliver systems ' contemplated herein may provide increased- household automation without extensive -wiring. For instance, the household wireless power delivery .syste may provide power to a system of automated windows, window treatments, doors, and or locks. Also, the household wireless power delivery system may be configured to accommodate room thermostats and other environmental monitoring devices in each .room. Additionally, the household wireless power delivery system may be operable to extend to exterior areas. For example, wireless power deliver).' to exterior areas may include providing electrical power io automated garden sprinklers, outdoor lighting, outdoor cameras, security devices, and/or motion, heat, or other sensors. Furthermore, the household wireless power delivery system ma allow controls (e.g., control panels for automated devices) to be flexibly and/or moveably located conveniently throughout the household.

|00178| As described above, example wireless power delivery systems may be configured io detect and identify various receivers within a local, proximity. For example, the household wireless power delivery system may b ' configured to locale household items that are resonantly coupled to it Furthermore, , the ability to locate household items need not be limited to electrically-powered devices that receive power from the wireless power delivery system. Non- electrically-powered devices, such as keys, tools, utensils,, and clothing, ma also be located if, for example, such objects may include a. characteristic tag that may be identifiable by the wireless power delivery system. For instance, the objects may incorporate an RFIO tag, may have a chaiacteristic RF impedance, or may include- reeeive-r esonator as described elsewhere herein. Other types of tags or location devices may be incorporated into objects so a to find them via the wireless power delivery system. | β 0Ι79| I» contrast to battery-powered devices, the household wireless power ' delivery systera may provide continuous power to a device without need for a batter or another t 'pe of energy-storage device. For instance, a robotic vacuum cleaning device receiving wireless power may move continuously within the household space without need for replacement O recharging of batteries.

f 001 $01 In another example implementation, a hospital wireless power delivery system is contemplated. Electrically-powered medical devices may be configured to receive power fro transmitters and/or repeaters located throughout the haspitai. The. hospital wireless power delivery system may provide advantages that are-similar to -the ' household wireless powe delivery system above. For instance, medical equipment and other devices can he easily and conveniently moved within the hospital without need fo new wired power connections. Additionally, the wireless power delivery system may he employed to locate hospital items that are coupled to the resonant oscillating fields of the wireless power delivery system. In. particular, surgical stems may include a tag with a receive-resonator -and/or a 'characteristic impedance detectable by the wireless power delivery system In such a scenario, locating surgical items may help ensure nothing is inadvertently left in a surgical site before closing the body cavity.

001811 Currently, the use exportable electronic devices, such as phones, computer tablets, computer laptops, and watches, may he limi ted by the extent of their rechargeable batten-' power or access to a fixed wall outlet. ' Furthermore, the recharging process often requires a power connector to he attached to, and detached from, the portable electronic devices. Repeated use of the power connector may lead to wear and tear and cause damage to the portable electronic devices.

001821 Some .portable electronic devices may employ conventional wireless power delivery- systems. As described above, however, the coupling factor k in such conventional systems must be maintained at a sufficiently high level in order to establish efficient power transfer, in other words, the- portable electronic devices must be to be located in close proximity to, and precisely positioned relative to, the transmitter, in conventional wireless power delivery systems, the transmitter must. typically have access to a fixed wall outlet. As such, compared to wired recharging which also requires access to a fixed wall outlet, conventional wireless power delivery systems merely eliminate the need to physically attach a power connector to fee portable elecirotiic device and provide no .additional positional freedom for fee use of fee portable electronic devices,

00i83J Thus, in yet another example implementation, wireless power delivery systems may be employed in common spaces, such as air ports, ears, planes, trains, buses, etc., to conveniently allow portable electronic devices to be recharged and/or powered wirelessly. The portable electronic devices may include reeeive-resonators that can be coupled to the wireless power deliver}-' system. In some cases, the recharging process may occur automatically without user action when a portable electronic device enters one of these common spaces. That is, the portable electronic device may automatically couple to wireless power delivery systems in proximity to the device. In other cases, a portable electronic device may need to be registered via a wireless power account and/or may need to be authenticated prior to receiving power from the wireless power delivery system. In some scenarios, the wireless power account may be a paid account that may be associated with a wireless communication network that may provide cellular (e.g. voice conununication) aad/or data services for the portable electronic device,

|00184] in a further example implementation, aspects of the present disclosure may be- employed to wirelessl assemble modular computer components. As shown in Figure 15, a computer system 1500 includes a plurality of modular computer components, which may include a computer processing unit main logic board (CPU/MLB) 1502a, a graphics processing- unit (GPU) 1502b, one or more hard disks (HD) 1502c, a secondary optical read/write (R W) device 1502d, and a wide area network (WAN) card l S02e. In other embodiments, the computer system 1500 may include odrer/addi ioaal computer components.

imim} The GPU 1502b, the HD 1502c, the R device 1502d, and he network card 1502e ma be communicatively coupled to the CPU/MLB 1502a. By exchanging data and other signals with the computer components 15G2b-e, the CPU/MLB 1502a can centrally control fee computer components I5Q2b-e. To establish such comniunieatioas, the components 1502a-e may include respective wireless communication interfaces 1504a-e as shown in Figure 15. For instance, fee wireless communication interfaces 15G4a-e may establish radio frequency (RF) commomcations (e.g., 60 Ghz RF) aad/or optical freespace communications betweea fee computer components I 502a-e.

O0186J The computer system 1500 also includes a wireless power delivery system to provide the components 1502a-e with power. In particular,- one or more transmitters 1-510 (and optionally one or more repeaters) are spatially organized to provide resonant oscillating fields within- a defined spatial bound 1301 , The spatial bound 1501, for instance:, may correspond to the interior space of a hard case for a computer deskiop/tower. Each transmitter 1510 may be coupled to a power source 1520 and may include a transmit-resonator 1516 to generate the resonant oscillating fields. The computer components 15Q2g-e may each ineliide a respective reeeive-resonato I506a~e -configured to he coupled to the resonant oscillating field(s). When located within the spatial bound 1501 , each computer component 1502a~e can recei ve power vi the resonant oscillating fieldfs) to perform its respective function, in some embodiments, the transmitters) 1510 may he integrated with the CPU/MLB 1502a to centralize control of the computer system 1 00 further.

|ββί ' 87| By -establishing wireless communications and receiving wireless power, the compoter components I502a~e within, the spatial bound 1501 can function together as a computer. Advantageously, the wireless configuration of the computer system 1500 eliminates tile need for a complex system of hardwired connections, e.g., wiring harnesses, to connect th computer components 502a~e. Additionally, the wireless configuratio facilitates Installation and removal of the computer components lS02a~e, e.g., from a computer hard case. As such, the computer components 1502a«e can be easily maintained, repaired, and/or replaced. The computer system 1500 can also be upgraded just by placing additional computer components, such as additional hard disks 1502c, in the spatial bound 1501 -without setting up any hardwired connections. In some embodiments, the CPU. 'MLB 1502a may detect the presence of new computer components via the wireless comim ications and thus incorporate the new computer components in the operation of the computer system 1500.

{ Wi 88| As described above, the wireless power delivery system ma employ side- channel eoraiMinkaCions to coordinate aspects of site power transfer. As such, each transmitter 1510 -may also include a wireless communicatio interface ' 1514 to communicate with eac of the computer components 1502a-e acting as receivers. In other words, the communication interfaces I504a-e may also be employed to provide side-channel ' communications with the transniitter s) 1510.

{00189) As the .computer- system 1500 -demonstrates, a system of components can be assembled according to a modular approach by employing a wireless power delivery system as well as wireless communications. Thus, in yet another example implementation, a computer data center may employ a system of transmitters and repeaters to allow computer servers to be implemented as modular components. The servers can receive power as long as they are. located within the computer data center. In addition, wireless communications, e.g., -f eespace optical communications, may ' be employed to allow data exchange between th servers. The wireless power delivery system and the wireless communications allow the servers to be easily deployed in the computer data center without setting up wired power and wired network connections. The servers can he easil maintained, repaired, and/or replaced. Additionally, the servers can be spatially organized in the computer data center with greater freedom. Although the transmitters may receive wired power, the servers are not limited to locations wh re wired power and/or wired network connections are accessible.

|00190] Because the computer data center uses less wired power and fewer wired network connections, the physical desig of the computer data center can place greater emphasis on other design considerations or features. For instance, the physical design can provide more optimal thermal management. Alternatively, .the physical desig may focus on lowering costs for building or implementing the computer data center.

G, Mobile Power-Delivery Systems

{001 11 Some de vices may operate out of range of a fixed resonant wireless po wer source, in some cases, it may be impractical or difficult to provide a fixed transmitter in a location where receivers operate or need to operate. Examples include field devices, such as mobile deli very/ transportaiion vehicles, remote .communication equipment, and clusters of devices in remote locations where fixed power sources are not . available,

00192] In accordance with example embodiments, system for resonant wireless power delivery can include a mobile node or device that is a hybrid transmitter/receiver fTX/RX) configured to move, travel, or "commute" to remote receivers and deliver power wirelessly based on the techniques described herein. More specifically, a hybrid TX KK device can include a transflaitter component (TX) having .functionaKty of a transmitter, a receiver (RX) component having functionality of a receiver, and a power store for storing power (e.g,, a batten.-) for supply to receivers. The power store -may also serve as a power supply for various functions of the ' hybrid TX/RX device including, but not limited to, mobility (commuting), communications, control, and processing. The XX/RX device can be configured in an autonomous -unmanned vehicle operational to travel between one. or more fixed transmitters and. one or more specified locations that may be host to one or more remote receivers. In the location of the one or more remote receivers, the XX component may function to wsrelessly transfer power from the power store to the on or more remote receivers, in the location of the fixed transmitter, RX component can be configured to receive power via wireless power transfer, and to use the received power to at least partially replenish (e.g., refill and or recharge) the power store.

1001 31 In an example embodiment, the hybrid TX RX device may include a high- density stored power source, such as liquid foe! or a fue-I cell. This source may be separate from the replenishahle power store. A high-density stored power source can be used to power operations of the hybrid TX/RX device and/or to provide power for wireless electrical power transfer to receivers,

f 00194] An autonomous unmanned vehicle can take on a variet of forms and modes of mobility. Non-limiting- examples include an unmanned aerial vehicle (OAV), an unmanned ground vehicle (UGV), and an unmanned marine vehicle (UMV). A non- limiting example of a UAV is a multi-copter configured for aerial flight between locations and hovering at individual locations. A non-limiting example of a UGV is a robotic wheeled vehicle configured for driving between locations and "paxMng" at individual locations, A non-limiting example of a UMV is a robotic surface boat configured for traveling over the surface of a body of water (e.g., ocean, lake, river, etc.) between locations and floating on the surface at individual locations. A UMV could also he a robotie submarine vehicle. In some examples, the autonomous unmanned vehicle may not necessarily park o hover at a location, but rather just "dri ve by" the location, possibly at a reduced speed compared to the speed of travel to or between locations.

001 51 Further, an autonomous unmanned vehicle can be fully autonomous or semi-autonomous.. A fully autonomous vehicle may be configured for operation without human assistance or intewmtioa, except possibly for human actions in loading or installing instructions prior to operation, for example, A partially autonomous vehicle may be configured, for operation with some degree of human assistance or i ntervention, such as remote or local control of at least some of the vehicle's operations. Unless otherwise specified or apparent from context, the term '"autonomous unmanned vehicle" shall be taken herein to refer to both fully and partially autonomous unmanned vehicles.

[00196] In an example embodiment, an autonomous unmanned vehicle can be a UAV. Herein, the terms "unmanned aerial vehicle" and "UAV" refer to any .autonomous or semi-autonomous vehicle that is capable of performin some functions without a physically- present, human pilot. Examples of flight-related functions may include, but are not limited to, sensing its environment or operating in the air without need for inpu from an operator, among others. The term "aerial vehicle" (manned or unmanned) used herein refers to a vehicle configured for flight, and, depending on context, applies either during flight : or when the aerial vehicle is not flying. The term "airborne vehicle" (manned or unmanned) refers to a vehicle (such as an aerial vehicle) that is flying (or during flight),

|001 7| A UAV may be autonomous or semi-autonomous. For instance, some functions could be controlled by a remote human operator, while other -functions- are carried out •autonomously. ' Further, a UAV may be -configured to allow a remote operator to take over functions that, can otherwise be controlled autonomously by the UAV. Yet further, a given type of function may be controlled remotely at one level of abstraction and performed autonomously at another level of abstraction. For example, a remote operator could control high level navigation, decisions for a UAV, such as by specifyin that the UAV should navel from one location to another (e.g., from 123 Main Street, Anytown, USA to 987 First Avenue, Anytown, USA), while th UAV's navigation system autonomously controls more fine-grained navigation decisions, such as the specific route to take between the two locations, specific flight controls to achieve the route and avoid obstacles while navigating the route, and so on. Other examples are also possible.

001 81 UAV ca be of various forms. For example, a UAV may take the form of a, rotorcraft. such as a helicopter or multicopter., a fixed-wrog aircraft, a jet aircraft, a ducted fail aircraft, a lighier-thaii-air dirigible such as blimp or steerable balloon, a tall-sitter aircraft, a glider aircraft:, and/or an omithopter, among other possibilities. Further, the terms "drone," "unmanned aerial vehicle system" C'lJAVS"), or "-unmanned aerial system" ( U UAS M ) may also be vised to refer to a LAV

001991 Figure 17 is a simplified illustration of a UAV, according to an example .embodiment In particular. Figure 17 shows an example of a rotorcraft 1700 that is -commortly referred to as a multicopter. M lticopter 1700 may also be referred to as a qoadcopter, as it includes four rotors 1710. t should be understood that example -embodiments may involve rotorcraft with more or less rotors than multicopter 1700. For example, a helicopte typically has two rotors. Other examples with three or more rotors are possible as well. Herein, the term "multicopter" refers to any rotorcraft having more than two rotors, and the term "helicopter * refers to rotorcraft having two rotors (e.g., a main rotor and a tail rotor).

|OO20O1 Referring to multicopter 1700 in greater detail, the four rotors 1710 provide propulsion a»d maneuverability for the multicopter 1700. More specifically, each rotor 1710 includes blades that are attached to a moto 1720. Configured as such the rotors may allow the multicopter 1700 to take off and land vertically, to maneuver in any direction, and/or to hover. Furthermore, the pitch of the blades may be adjusted as a group and/or differentially, and may allow a multicopter 1700 to perform three-dimensional aerial -maneuvers such as a upside- down hover, a continuous tail-down "tie-toe," loops, loops with pirouettes, stall-turns with pirouette, knife-edge, I rneltaann, slapper, and traveling flips, among others. When the pitch of ah blades is adjusted to perform such aerial maneuvering, this may be referred to as adj usting the "collective pitch" of the multicopter- 1700. Blade-pitch adjustment may be particularly useful for rotorcraft with substantial inertia in the rotors and/or drive train, but is not limited to suc rotorcraft.

{00201} Additionally or alternatively, multicopter 1700 may propel and maneuver itself and adj ust the rotation rate of the motors, collectively or dirTerentially. This technique may ¬ be . particularly useful for small electric rotorcraft with low inertia in the motors and/or rotor system, but is not limited to such rotorcraft. 100202] Multicopter 1700 also includes a central enclosure 1730 with a hinged lid 1735. The central enclosure may contain, e.g., control electronics such as .an inertia! measurement unit (IMU) and/or -an electronic speed controller, batteries, other sensors, and/or a payload, among other possibilities,

{00203} The illustrative multieopter 1700 also includes landing gear 1740 to assist with controlled take-offs and landings. In other embodiments, multicopters sad other types of UAVs without landing gear are also possible.

100204] In -further aspect, . - ulticopier 1700 includes rotor protectors 1750. Such rotor protectors 1750 ca .serve multiple purposes, -such as protecting the rotors .17.10 from damage if the multicopter 1700 strays too close to an object, protectin the multicopter 1700 structure from damage, and protecting nearby objects from being damaged by the rotors 1710. It- should be understood that in other embodiments, multicopters and other types of UA Vs without rotor protectors are also possible. Further, rotor protectors of different shapes, sizes, and function- are possible, without departing from, the scope of the invention.

100205] A multicopter 1700 may control Ihe direction and/or speed of its movement by controlling its pitch, roll, yaw, and or altitude. To do so, multicopter 1700 may increase -or decrease the speeds at which the rotors 3710 spin. For example, by .maintaining a constant speed of three rotors 1710 and decreasing the speed of a fourth rotor, the multicopter 1 00 can roll right, roll left, pitch forward, or pitch backward, depending upon which motor has its speed decreased. Specifically, the .multicopter ma roll In the direction of the motor with the decreased speed. As another example, increasing or decreasing the speed of all rotors 1710 simultaneously can result in the multicopter 1700 increasing or decreasing its altitude, respectively. As yet another example, increasing or decreasing the -speed of rotors 1710 that are taming in the same direction can result in the multicopter 1700 performing a yaw-left or yaw- right movement. These are but a few examples of the different types of movement: that can be accomplished by independently or collectively adjusting the RFM and/or the direction that rotors Y 10 ' are. spinning.

{00206} Figure- 18 i a simplified illustration of a UAV, according" to an example embodiment. In particular. Figure 1-8 shows - an example of a tail-sitter UAV 1800. In the illustrated example, the tail-sitter UAV 1800 has fixed wings 1802 to provide lift and allow the UAV to glide horizontally (e.g., along die .x-axts, in a position that is approximately 'perpendicular to the position shown in Figure IS). However, the fixed wings 1802 also allow the tail-sitter UAV 1800 take off aad land vertically on its own.

£08207! Fo example, at a launch site, tail-sitter UAV 1800 may be positioned vertically (as shown) with fins 1804 and/or wings 1802 resting on the ground and stabilizing the U A V * in the vertical position. The tail-sitter UAV 1800 may then take off by operatin g propellers 18.06 to generate the upward thrust (e,g,, a thrust that is generally along the y-axis). Once at a suitable altitude; the tail-sitter UAV 1800 may use its flaps 1808 to reorient itself in a horizoratai position, such that the fuselage 1810 is closer to being aligned with the x-axis than the y-axis. Positioned horizontally, the propellers 1806 may provide forward thrust ' so that the tail-sifter UAV 1800 can fly in. a similar manner as a typical airplane.

J0&208J Variations on the illustrated tail-sitter UAV .1800 are possible. For instance, tail-sitters UAVs with more. or less propellers, or that utilize a ducted fan or multiple ducted fans, are also possible. Further, different wing configurations with more wings (e.g., an "x-wing * ' configuration, with four wings), with les wings, or even with no wings, are also possible. More generally, it should be understood that other types of tail-sitter UAVs aad variations on the illustrated tail-sitter UAV 1800 are also possible.

O02O91 As noted above, some embodiments may involve other types of UAVs, in addition or in the alterative to muldcopters. For instance. Figures 3 A and 1 B are simplified illustrations of other types of UAVs, according to example embodiments.

f ' OO210J in particular, Figure 19A shows an example of a fixed-wing aircraft 1900, which may also be referred to as an airplane, an aeroplane, or simply a plane, A fixed-wing aircraft 1 00, as the name implies, has stationar wings 1 02 that generate lift based on t e wing shape and the vehicle's forward airspeed. This wing cenfigaratiea is different from a rotorcraft's configuration, which produces lift through rotating rotors about a fixed mast, and ait oroithopter's configuration, which produces lift by flapping wings.

f 00211! Figure I9A depicts some common -structures used in a fixed-wing aircraft 1900. In particular, fixed- wing aircraft 1900 includes a fuselage 1904, two horizontal wings 1902 with an airfoil-shaped cross section to produce an aerodynamic force, a vertical stabilizer 1906 (or lit!) to stabilize the plane's yaw (torn left, or right), a horizontal stabilizer 1908 (also referred to as an. elevator or tadplaiie) to stabilize pitch (tilt up or do n),' landing gear 1910, and. a propulsion unit 912, which can include a motor, shaft, and propeller.

{00212} Figure 19B shows an example of an aircraft 1950 with a propeller i a pusher configuration. The term "pusher" refers to the fact that the propulsion unit 195S is mounted at the back of the aircraft and "poshes" the vehicle forward, in. contrast to the propuls ion uni t ' being mounted at the front of the aircraft. Similar to the description provided for Figure Ϊ 9A t Figure 19B depicts common structures used in the pusher plane: a fuselage 1952, two horizontal wings 1954, vertical stabilizers 1956, and a propulsion unit 1958, which can include a motor, shaft, and propeller.

|IKI213| UAVs can be launched in various ways, using various types of launch systems (which may also be referred to as deployment systems), A very simpl way to launch a UAV is a hand launch. To perform a hand launch, a user holds a portion of the aircraft, preferably away from the .spinning rotors, and throws the aircraft into the air while contemporaneously throttling the propulsion unit to generate lift.

1002X4 J Rather than using a hand launch procedure in which the person launching the vehicle is exposed to risk from the quickly spinning propellers, a stationary or mobile launch station can be utilized. For instance, a launch system can include supports, angled and inclined rails, and a backstop. The aircraft begins the launch system stationar on the angled and inclined rails and launches, by sufficiently increasing the speed of the propeller to generate forward airspeed along the incline of the launch system. By the end of the angled and inclined rails, the aircraft can have sufficient airspeed to generate lift. As another example, a launch system may include a rail gun or cannon, either of which may launch a UAV b thrusting the UAV into flight. A launch system of this type may launch a UAV quickly and/or may launch a UAV far towards the UAVs destination. Other types of launch systems may also be utilized.

|002 ' X$] In some cases, there ma he no separate launch system for a UAV, as a UAV may be configured to launch itself. For example, a "tail sitter" UAV typically has fixed wings to provide lift and allow the UAV to glide, but also is configured to take off and land vertically on its own. Other examples of self-launching UAVs are also possible.

|0Θ216| hi accordance with example embodiments, a mobile TX/RX device ma travel to a location of a receiver that is otherwise out or range of any other fixed transmitter. At tbe location, the mobile TX/R device may then position itself sufficiently close to the receiver so that the receiver can couple t an oscillating field -produced, by the TX component of the mobile TX RX device. The mobile device may determine an an appropriate distance of approach according to its resonant wavelength, for example. It ma also determine the distance to the receiver using a range detector, such as laser. Additionally or alternatively, it may use a test- signal generator in a mode that transmits a test pulse, as described above, and measure a roinid- trip delay based on a reflection from the receiver. Once the mobile TX/RX device determines it is sufficiently close to the receiver, it may begin wirelessly transferring power from its power store (e.g., a battery) to the receiver according the techniques described above.

(00217J In an example embodiment, the mobile TX/RX device ma travel to a location of a transmitter. At the location, the mobile TX/RX ' device may then position itself sufficiently close to the .transmitter .so that its RX component can couple an oscillating field of the transmitter. The mobile device may determine the distance to the transmitter using a range detector, such as a laser. Additionally or alternatively, it may use a test-signal generator in a mode that transmits a test pulse, as described above, and measure a round-trip dela based on a reflection from, the transmitter. Once the mobile TX RX device determines is it sufficiently clos to the transmitter, it may request wireless power according the techniques described above, it may use the received wireless power to power its own operations (e.g., flying or driving) and/or to replenish its power store (e.g., recharging a battery) for subsequen delivery of wireless power to one or more remote recei vers,

f ' 00238j In an example embodiment, the mobile TX/RX device may include a far- field receiver configured for receiving power from a far-field beaming transmitter. Nonexclusive examples of a far-field beaming transmitter include a microwave transmitter and a laser transmitter. I either example, power may be wirelessly transmitted to the far-field receiver at a level sufficient to replenish the power store. ' Far-field beaming of power may be used whe a line-of-sight path between the far- field transmitter and the far-field receiver is available. {0Θ219| Operations relating to mobile TX RX device described above may foe implemented as a method by one or more processors of the mobile TX/RX device. In particular, the mobile TX RX device, more generally referred to as a mobile wireless power-delivery device (MWPD), can include an autonomous mobile vehicle,, a power source,, and a transmitter device including a transmit-resonator that is configured to couple power from th power source into a first oscillating field generated fay the traasmit-resonator resonating at a first resonant frequency. The MWPD can. also include a receiver device including a receive-resonator configured to resonate at a second resonant frequency in response to being situated in a second oscillating field generated by a power-supply transmitter other than the transmitter device of the MWPD. Further, in response to the receive-resonator resonating ai the second resonant frequency, the receiver device may transfer -at least a portion of power of the second oscillating field to a rechargeable component of the power source. The first and second oscillating fields can each be an oscillating electric field, an oscillating magnetic field, or both. An example method is illustrated in the form of a fiowehart in Figure 20.

|O0220| At step 2002, a controller of the ' WPD causes the autonomous vehicle to move to a first location i sufficient proximity to a remote receiver to cause the remote receiver to couple with the first oscillating field. Step 2004 includes the controller causing the autonomous vehicle to transfer power to the remote recei er via the first oscillating field.

|O022iJ At ste 2006, the controller of the MWPD causes the autonomous vehicle to move to a second location in sufficient proximity to the power-supply transmitter to cause the receiver device to couple with the second oscillating field. Step 2008 includes causing the ' autonomous vehicle to receive powe from the power-supply transmitter via the second oscillating field.

{ ' 002221 it should be understood that method 2000 is described herein for purposes of example only. As such, those skilled in the art will appreciate that other arrangements and other elements (e.g. machines,, interfaces, functions, orders, and groupings of functions, etc.) can be used instead, and some elements may be omitted altogether according to the desired results. Further, many of the elements that are described are- functional entities that may be implemented as discrete or distributed components or in conjunction with other components, in any suitable combination nd location.

00223] Figure 21 depicts a sintplified block diagram of a MWPD 2100 in accordaiice wit an example embodiment As shown, the MWPD 2100 includes a representative autonomous vehicle 2102, which in practice may constitute a physical platform for sonie or allof the other components of the MWPD 2100. The MWPD 210 also includes a power source 2104, a transmitter 2106, and a receiver 2108, By way of example, the components are depicted as being connected by a bus 21 12, which could support communication between components, as well as power supply and/or other operational aspects of the MWPD 21.00. Although not shown in Figure 2100, the MWPD 2100 could include a payioa for carrying out other tasks.

|§0224] B way of example. Figure 2100 also includes a representative remote receiver 21 14, including a receiver load, and a -representative fixed transmitter 21.16, including its- own power supply. Example operation, such as described above and discussed in connection with Figure- 20, is illustrated conceptuall by the motion arrow 21 17 representing travel of the MWPD 100 between the fixed transmitter 21 16 and the remote receiver 114. While at the location of the fixed, transmitter 2116, the receiver 2108 of the MWPD 21 0 may receive power wirelessl via an oscillating field 21 15 generated by the fixed transmitter 21 16. The received power may be used to power operations of the .MWPD 2100 and possibl to recharge or replenish the power source 2104 of the MWPD 2100. While at the location of th remote receiver 1 14,, the MWPD may deliver power wirelessly to the remote receiver via an oscillating field 21 3 generated by the transmitter 2106 of the MWPD 2100. It will be appreciated that the simplified block diagram of Figure 21 and the simplified example operation description are intended for illustrative purposes.

HI. Conclusion '

f§0225| While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for provided for explaaatory purposes and are not intended to he limiting, with the true scope being, indicated by the following claims.