APPARATUS AND METHOD FOR AFFECTING AN ELECTRIC FIELD DURING A COMMUNICATION

FIELD OF APPLICATION

Embodiments of the present invention relate generally to apparatuses and methods for communicating, and, more particularly, to apparatuses and methods for communicating via a medium while affecting the strength and/or direction of an electric field experienced by the medium.

BACKGROUND INFORMATION

A dielectric, or electrical insulator, is a substance that is highly resistant to electric current. As a consequence of this relative lack of internal charge mobility (when compared, say, to a conductor), dielectric materials are subject to a phenomenon wherein charges within constituent atoms or molecules are redistributed in response to exposure to an applied electric field. Such charge redistribution can be due either to an alteration of the geometry of the molecules or to a spatial reorientation of the molecules. In either case, the properties of a dielectric may be dependent on the electric field to which the dielectric material is currently exposed. When an applied electric field is removed, the material may return to an unaltered or "ground" state. The rate at which the dielectric material returns to the ground state when the applied electric field is removed, or the rate of "relaxation," may depend on the mechanism by which the charges were redistributed (i.e., whether the charge redistribution was due to reshaping or reorienting the molecules).

Dielectric materials are often incorporated into structures such as waveguides that are utilized in signal or energy transfer. These dielectrics may be incorporated as the main wave transmission medium, as a component that separates electrical conductors, or in both capacities. Regardless of the manner in

which a dielectric is incorporated into a waveguide, the transmission properties of the waveguide will often depend on the properties of the incorporated dielectric material. In several applications, transmission properties of dielectrics have been controlled through the application of external electric fields, thereby tailoring the transmission properties for the application at issue. For example, in optical beam emission applications, a location-dependent electric field can be applied to a planar dielectric being irradiated with a planar optical wave. Due to the resultant spatially- varying dielectric constant of the dielectric material, the wave is reoriented on passing through the planar dielectric. As such, the electric fields can be adjusted to steer the beam. However, while some applications do exist for tuning the dielectric properties of a dielectric via the application of a varying electric field, the number of applications for which this strategy has been utilized has been limited by the relaxation rate for these materials.

BRIEF SUMMARY

In light of the foregoing background, provided are improved apparatuses and methods for communicating via a medium while affecting the strength and/or direction of an electric field experienced by the medium. By affecting the strength and/or direction of an electric field experienced by the medium, the manner in which signals travel in the medium may be modified.

In one aspect, an apparatus is provided that includes a signal guide configured to have an operative state, in which a signal propagates therealong, and an inoperative state, in which no signal is propagated therealong. The signal guide may include a dielectric component, such as a dielectric component comprised of a liquid crystal polymeric material. At least first and second electrodes may be disposed on opposing sides of the signal guide. For example, the signal guide may be configured to propagate the signal along a propagation direction and the electrodes may be disposed along a transverse direction that is generally orthogonal to the propagation direction. A voltage controller may charge the first and second electrodes with common polarity to one another when the signal guide is in the operative state, and may at least temporarily charge the first electrode with polarity opposite to that of the second electrode when the

signal guide is in the inoperative state. The apparatus may include a detection unit in communication with the voltage controller and configured to detect whether the signal guide is in the operative or inoperative state.

In one embodiment of the apparatus, the signal guide may include a conductor that generally defines an electrode plane with the first and second electrodes, as well as a reference layer spaced from the conductor in a first direction generally orthogonal to the electrode plane. A dielectric component may be disposed between the conductor and the reference layer. The apparatus may be configured such that, when the signal guide is in the operative state, a potential difference exists between the conductor and the reference layer that is substantially the same as respective potential differences between each of the first and second electrodes and the reference layer. The apparatus may be further configured such that, when the signal guide is in the inoperative state, a potential difference exists between the conductor and the reference layer that is at least temporarily small relative to a potential difference between the first and second electrodes.

In another aspect, another apparatus is provided that includes a signal guide having a conductor and a reference layer, and, in some cases, a dielectric component disposed therebetween. A signal source communicates with the signal guide and is configured to have a signaling state that is substantially immediately followed by a non-signaling state. In the signaling state, a first potential difference is established between the conductor and the reference layer, while in the non-signaling state, a second potential difference is transiently established between the conductor and the reference layer, the second potential difference being of opposite polarity to the first potential difference.

In yet another aspect, an apparatus is provided that includes signal guiding means for guiding a signal. The signal guiding means may include a dielectric material and is configured to have an operative state in which the at least one signal propagates therealong and an inoperative state in which no signal is propagated therealong. Also included is field establishing means for establishing a variable electric field within the dielectric material. The field establishing means is configured to establish a first electric field directed in a first direction

when the signal guiding means is in the operative state and to at least temporarily establish a second electric field directed in a second direction that is different from the first direction and rotated at least 90 degrees from, and in some cases substantially opposed to, the first direction when the signal guiding means is in the inoperative state. The field establishing means may be configured to establish the first electric field for a first time period and to establish the second electric field substantially immediately subsequent to the first time period.

In still another aspect, a method is provided that includes providing a signal guide including a dielectric material. A signal is propagated along the signal guide, thereby establishing an operative state, the signal guide otherwise being in an inoperative state. A first electric field directed in a first direction is established when the signal guide is in the operative state. A second electric field directed in a second direction that is different from the first direction and rotated at least 90 degrees from the first direction is at least temporarily established when the signal guide is in the inoperative state.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

Fig. IA is a schematic side view of an exemplary embodiment of a microstrip waveguide that includes a conductor, a reference layer, and a dielectric material between the two;

Fig. IB is a schematic perspective view of the microstrip waveguide of Fig. IA, illustrating signal propagation along the waveguide;

Figs. 1C and ID are schematic side views of the microstrip waveguide of Fig. IA, illustrating the establishment of first and second electric fields when the waveguide is in an operative or inoperative state, respectively;

Fig. 2 is a flow chart representing an exemplary embodiment of a method for affecting the direction of the respective electric field experienced by the dielectric material of a waveguide;

Fig. 3 A is a schematic perspective view of an embodiment of an apparatus for communicating via a medium while affecting the strength and/or direction of an electric field experienced by the medium;

Fig. 3B is a schematic side view of the apparatus of Fig. 3 A; Figs. 3C and 3D are schematic side views of the apparatus of Fig. 3 A, illustrating the variable charging of the electrodes;

Figs. 4A is a schematic side view of another embodiment of an apparatus for communicating via a medium while affecting the strength and/or direction of an electric field experienced by the medium; and Figs. 4B and 4C are schematic side views of the apparatus of Fig. 4A, illustrating the operation of the apparatus.

DETAILED DESCRIPTION The present inventions now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the inventions are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.

The present application is generally directed to methods and apparatuses for communicating via a medium while affecting the strength and/or direction of an electric field experienced by the medium. By affecting the electric field experienced by the medium, the transmission properties of the medium may, in some embodiments, be consequently affected. As an example of an apparatus in which the direction of an electric field experienced by a communications medium may be affected while communicating via that medium, referring to Figs. IA and IB, therein is shown signal guiding means 102 in the form of a microstrip waveguide that includes a conductor 104 and a reference layer or ground plane 106. Other types of signal guides, whether electromagnetic waveguides or optical waveguides, may be used for signal guiding means 102, including, for example, a coaxial transmission line, or a strip transmission line. Signal guiding

means 102 may be an isolated communications path, or may be part of a larger circuit or communications system. Signal guiding means 102 may include a dielectric material 108, such as, for example, porcelain, glass, or plastic. In one exemplary embodiment, the dielectric material 108 may be a liquid crystal polymeric material, such as 4,4'-dimethoxy azoxybenzene, N-(4- methoxybenzylidene)-4'-n-butylaniline, and/or 4-cyano-4'-n-pentylbiphenyl. Referring to Figs. IB, 1C, and ID, signal guiding means 102 may be configured to allow signals s to propagate therealong, for example, between a signal source and a signal receiver (neither of which is shown). As such, signal guiding means 102 will have an operative state (Figs. IB and 1C) in which a signal propagates along signal guiding means 102 and an inoperative state (Fig. ID) in which no signal so propagates. It is understood that as a signal s propagates along signal guiding means 102 in the operative state, the effects of the * signal s, such as resulting electric and magnetic fields, may extend beyond conductor 104, and may extend into the dielectric material 108 between the conductor 104 and the reference layer 106.

Field establishing means (not shown in Figs. 1 A-ID, but shown and described elsewhere) may be utilized to establish a variable electric field within dielectric material 108. For example, the field establishing means may be configured to establish, perhaps temporarily, a first electric field El directed in a first direction Dl when signal guiding means 102 is in the operative state, this condition being demonstrated in Fig. 1C. The field establishing means may be further configured to establish, perhaps temporarily, a second electric field E2 directed in a second direction D2 when said signal guiding means 102 is in the inoperative state, this condition being demonstrated in Fig. ID. Second direction D2 is different from, and is rotated at least 90 degrees from, the first direction Dl. In some embodiments, second direction D2 may be rotated about 180 degrees from the first direction Dl, such that the second direction D2 is approximately opposed to the first direction Dl. The establishment of the first electric field may be for a first time period that is substantially immediately followed by a second time period in which the second electric field is established. It is noted that the propagation of signal s along signal guiding means 102 will

likely affect the field present in and experienced by the dielectric material. Field establishing means may be chosen and configured to account for this effect. Examples of different types of field establishing means are provided below.

Referring to Figs. 1 A-ID and 2, the structure described for signal guiding means 102 allows for affecting the direction of the respective electric field experienced by dielectric material 108 when signal guiding means 102 is in the operative or inoperative state. At various times, a signal may propagate along signal guiding means 102 (see Block 210), this signal propagation establishing the operative state of signal guiding means 102. At the times when signal guiding means 102 is in the operative state, the first electric field El is established in dielectric material 108 so as to be directed in the first direction Dl (see Block 212). When signal guiding means 102 is not in the operative state (Block 214), the second electric field E2 may be established (Block 216), at least temporarily, and directed in the second direction D2. For example, the first electric field may be established for a first time period, possibly coincident with the extent of an existing operative state, and the second electric field may be established substantially immediately subsequent to the first time period, or upon exiting the prior operative state. This second electric field may be transiently established for a period of time shorter than the extent of an existing inoperative state. The process can then be repeated for subsequent signals {i.e., returning to Block 210), which may or may not have similar electromagnetic properties to earlier signals (i.e., voltage, wavelength, etc.).

Referring to Figs. 3 A-3D, in one exemplary embodiment, field establishing means may include at least a first electrode 320a and a second electrode 320b positioned at opposing sides of a signal guide 302. For example, signal guide 302 may include a conductor 304, which together with first electrode 320a and second electrode 320b may generally define an electrode plane PE. Signal guide 302 may also include a reference layer 306 spaced from conductor 304 in a direction D generally orthogonal to the electrode plane PE, and a dielectric component 308 disposed between conductor 304 and reference layer 306. Signal guide 302 may be configured to communicate with a signal source (not shown) and a signal receiver (not shown), such that signals propagate

along signal guide 302 in a propagation direction/?. First and second electrodes 320a, 320b may be disposed transversely to conductor 304 , where the transverse direction t that is generally orthogonal to the propagation direction/?, and may extend along the propagation direction/?. The exemplary embodiment of the field establishing means may further include a voltage controller 322 that is in communication with, and configured to independently and variably charge, first and second electrodes 320a, 320b. For example, voltage controller 322 may include first and second variable voltage sources 324a, 324b associated with first and second electrodes 320a, 320b, along with a processing unit 326 or other logical component that allows for control of the output of the variable voltage sources 324a, 324b. In an alternative example, voltage controller 322 may include circuitry that appropriately conditions a single voltage source for use in charging both first and second electrodes 320a, 320b.

When signal guide 302 is in the operative state, voltage controller 322 may charge first and second electrodes 320a, 320b with common polarity to one another, for example, so that both electrodes 320a, 320b are charged positively. When signal guide 302 is in the inoperative state, voltage controller 322 may charge first electrode 320a to have a polarity opposite to that of second electrode 320b, for example, so that first electrodes 320a is negatively charged and second electrode 320b is positively charged. Voltage controller 322 may include or communicate with a detection unit 328^ perhaps coupled to processing unit 326, which detects whether signal guide 302 is in the operative or inoperative state. Subsequent to establishing the inoperative state, signal guide may again move to an operative state, which may or may not be similar to the prior operative state. In some embodiments, using voltage controller 322 to charge electrodes 320a, 320b in the manner described above may lead to two distinct states of the signal guide 302. First, when signal guide 302 is in the operative state, a potential difference may exist between conductor 304 and reference layer 306 that is substantially the same as respective potential differences between each of first and second electrodes 320a, 320b and reference layer 306. In this condition, an electric field E may exist in dielectric material 308 that is substantially aligned with direction D. Second, when signal guide 302 is in the

inoperative state, a potential difference may exist between conductor 304 and reference layer 306 that is small relative to a potential difference between first electrode 320a and second electrode 320b. In this condition, an electric field E may exist in dielectric material 308 that is substantially aligned with direction t. Referring to Figs. 4A-4C, therein is shown another exemplary embodiment of an apparatus for communicating via a medium while affecting the strength and/or direction of an electric field experienced by the medium. The apparatus includes another exemplary embodiment of the field establishing means, which in this case includes a signal source 430 that communicates with a signal guide 402 having a conductor 404, a reference layer 406, and a dielectric material 408 between the two. Signal source 430 may be, for example, a variable voltage supply, a variable current supply, or a function generator. Signal source 430 may be configured to have a signaling state that is substantially immediately followed by a non-signaling state. In the signaling state, a first potential difference may be established between conductor 404 and reference layer 406. In the non-signaling state, a second potential difference of opposite polarity to the first potential . difference may be established, perhaps transiently, between conductor 404 and reference layer 406.

For example, signal source 430 may be a variable voltage source that emits a voltage that varies over time as shown in Fig. 4A. The voltage has a first value Vl in the time period Tl, the voltage Vl being associated with a signal (i.e., Tl is the duration of a signaling state). The voltage has a second value V2 over a second time period T2 that immediately follows 77. Time period T2 may be part of time period T3, which corresponds to a non-signaling state. V2 is generally not associated with the communication of information, and is simply provided in order to influence the condition of the signal medium. By operating signal source 430 in this manner, electric fields of opposite direction may be respectively established in dielectric material 408 during the time periods Tl and T2 (or Tl and T3). In some cases, the duration of T2 may be short, such that voltage V2 is essentially a pulse. In other cases, the signal source 430 may be configured to have a first signaling state during time period Tl in which a voltage Vl is applied and a second signaling state during time period T3 in which some other voltage is

applied, and may be configured to emit a non-signaling voltage V2 at a time between the first and second signaling states.

Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. For example, it is also noted that conductors incorporated as part of signal guides need not carry zero or a trivial applied voltage when in the "inoperative state," but may simply carry a voltage that is different from that applied during the "operative state." As such, it may be possible to propagate a signal during the "inoperative state," albeit one that is different from that propagated during the operative state. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.