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Title:
WIRELESS POWER SUPPLY EQUIPMENT
Document Type and Number:
WIPO Patent Application WO/2019/175031
Kind Code:
A1
Abstract:
A wireless power supply equipment is provided. The wireless power supply equipment includes: a base including a wireless power supply transmitting coil and an antenna; an extension dock including a wireless power supply receiving coil, an antenna, and a connection interface; a rotation shaft configured to pivotally connect the base and the extension dock; and an application device configured to be connected to the extension dock through the connection interface.

Inventors:
WANG, Shaoyong (C/O: Tyco Electronics Co. Ltd, Building A5, No.1528 Gumei Road, Caohejing,Xuhui District, Shanghai 3, 200233, CN)
FENG, Yulin (C/O: Tyco Electronics Co. Ltd, Building A5, No.1528 Gumei Road, Caohejing,Xuhui District, Shanghai 3, 200233, CN)
SONG, Yuming (C/O: Tyco Electronics Co. Ltd, Building A5, No.1528 Gumei Road, Caohejing,Xuhui District, Shanghai 3, 200233, CN)
Application Number:
EP2019/055783
Publication Date:
September 19, 2019
Filing Date:
March 07, 2019
Export Citation:
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Assignee:
TYCO ELECTRONICS (SHANGHAI) CO. LTD. (F/G Section, 1/F Building 15,999 Yinglun Road,Pilot Free Trade Zone, Shanghai 8, 201208, CN)
TYCO ELECTRONICS UK LTD (Faraday Road, Dorcan, Swindon Wiltshire SN3 5HH, SN3 5HH, GB)
International Classes:
H02J5/00; H01F38/14; H02J50/12; H04B5/00
Domestic Patent References:
WO1998052350A11998-11-19
Foreign References:
EP2916469A12015-09-09
JP2009200750A2009-09-03
Other References:
None
Attorney, Agent or Firm:
MURGITROYD & COMPANY (Scotland House, 165-169 Scotland Street, Glasgow str G5 8PL, G5 8PL, GB)
Download PDF:
Claims:
What is claimed is,

1. A wireless power supply equipment, comprising:

a base comprising a wireless power supply transmitting coil and an antenna;

an extension dock comprising a wireless power supply receiving coil, an antenna, and a connection interface,

a rotation shaft configured to pivotally connect the base and the extension dock; and an application device configured to be connected to the extension dock through the connection interface.

2. The wireless power supply equipment according to claim 1, wherein the rotation shaft is provided on the base.

3. The wireless power supply equipment according to claim 1, wherein the rotation shaft is provided on the extension dock.

4. The wireless power supply equipment according to claim 1, wherein the wireless power supply transmitting coil includes an annular coil having an annular shape, and the rotation shaft passes through the annular coil.

5. The wireless power supply equipment according to claim 1, wherein the wireless power supply transmitting coil comprises an outer ring and an inner ring wound in opposite directions so as to reduce an eddy current loss on the metal rotation shaft.

6. The wireless power supply equipment according to claim 1, wherein the wireless power supply receiving coil comprises an outer ring and an inner ring wound in opposite directions so as to reduce an eddy current loss on the metal rotation shaft.

7. The wireless power supply equipment according to claim 1, wherein the antenna includes a near field communication antenna.

8. The wireless power supply equipment according to claim 1, wherein the connection interface includes a power interface and a network interface.

9. The wireless power supply equipment according to claim 1, wherein the application device includes an audio device.

10. The wireless power supply equipment according to claim 9, wherein the audio device includes a camera.

11. The wireless power supply equipment according to claim 9, wherein the application device includes a video device.

12. The wireless power supply equipment according to claim 11, wherein the video device includes a display.

13. The wireless power supply equipment according to claim 9, wherein the application device includes a human-machine interactive device.

Description:
Wireless Power Supply Equipment

TECHNICAL FIELD

The present disclosure relates to a wireless power supply equipment.

BACKGROUND

In the prior arts, there are audio/video products that need to operate while rotating, and a slip ring is generally used as a connector for electrical energy and electrical signals. Long term friction between the slip ring and an electrical brush may result in poor contact, which may cause product instability.

Antennas commonly used in smart home appliances or electronic devices comprise a dipole antenna, an inverted-F antenna and the like. These antennas each have a simple structure and high efficiency, and are suitable for a far field communication with a certain distance (R»2D2/k, where R is a distance between two antennas for transmitting signals to each other, D is the maximum outer size of the antenna, and l is an operating wavelength of the antenna). Recently, with increasing and wide application of wireless power supply technology in the field of smart home appliances, a demand for short-range communication with high transmission rate and low far-field radiation leakage has become more and more intense. At present, a NFC antenna may be used for short-range communications and has a low far-field radiated power. However, due to its low operating frequency and narrow bandwidth, the NFC antenna cannot realize high-speed communications. In addition, the antenna as described above is generally used for communication in a stationary state. When two antennas need to be rotated mutually, for example, when one antenna is mounted on a wireless high-definition camera, which is powered wirelessly, a relative rotational motion may be generated between the two antennas. Since the NFC antenna is a linearly polarized antenna, and the distance between the two antennas often changes greatly during the rotation, a signal intensity received by the antennas also changes drastically. In the related art, signal intensity and signal reception quality are generally ensured by increasing transmission power. However, increasing the transmission power may cause communication signals to be leaked into the surrounding environment and is easily eavesdropped by others, thus reducing safety and security of the communication. Therefore, the existing antennae are not suitable for security devices having strict anti-eavesdropping requirements.

SUMMARY

An object of the present disclosure is to address at least one of the above and other problems and defects existing in the prior arts.

In accordance with an aspect of the present disclosure, there is provided a wireless power supply equipment comprising: a base including a wireless power supply transmitting coil and an antenna; an extension dock including a wireless power supply receiving coil, an antenna, and a connection interface; a rotation shaft configured to pivotally connect the base and the extension dock; and an application device configured to be connected to the extension dock through the connection interface.

In accordance with another aspect of the present disclosure, there is provided a wireless power supply product comprising: a base including a transmitting coil and an antenna; an extension dock including a receiving coil, an antenna, and a connection interface; a rotation shaft configured to pivotally connect the base and the extension dock; and an application device configured to be connected to the extension dock through the connection interface.

In accordance with yet another aspect of the present disclosure, there is provided a wireless communication product comprising: a base including a transmitting coil and an antenna; an extension dock including a receiving coil, an antenna, and a connection interface; a rotation shaft configured to pivotally connect the base and the extension dock; and an application unit configured to be connected to the extension dock through the connection interface.

In accordance with still another aspect of the present disclosure, there is provided a product capable of simultaneously implementing wireless power supply and wireless communication, the product comprising: a base including a transmitting coil and an antenna; a extension dock including a receiving coil, an antenna, and a connection interface; a rotation shaft configured to pivotally connect the base and the extension dock, the extension dock being configured to be connected to an application device through the connection interface.

In the above various embodiments of the disclosure, any one of the transmitting antenna and the receiving antenna comprises a substrate and upper and lower circular metal strips formed on upper and lower surfaces of the substrate. The transmitting antenna and the receiving antenna may be rotated about the same central axis. When one of the transmitting antenna and the receiving antenna is rotated with respect to the other, the distance between them will not be changed. Therefore, it is possible to ensure signal strength and signal receiving quality without increasing transmission power. Moreover, since it does not need to increase the transmission power, far field radiation energy of the antenna is very low. Therefore, it is possible to effectively prevent communication signals from being leaked into the surrounding environment and being eavesdropped by others, thereby improving safety and confidentiality of the communication.

Other objects and advantages of the disclosure will become apparent from the following description of the disclosure when taken in conjunction with the accompanying drawings, and may give a comprehensive understanding of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the disclosure will become more apparent by describing in detail exemplary embodiments thereof with reference to the accompanying drawings, in which:

FIG. 1 shows a schematic perspective view of a transmitting antenna when viewed from the front according to an exemplary embodiment of the disclosure;

FIG. 2 shows a schematic perspective view of the transmitting antenna when viewed from the back according to an exemplary embodiment of the disclosure;

FIG. 3 shows a schematic exploded perspective view of the transmitting antenna according to an exemplary embodiment of the disclosure in which a radio frequency resistor is shown;

FIG. 4 shows a schematic perspective view of a receiving antenna when viewed from the front according to an exemplary embodiment of the disclosure;

FIG. 5 shows a schematic perspective view of the receiving antenna viewed from the back according to an exemplary embodiment of the disclosure;

FIG. 6 shows a schematic exploded perspective view of the receiving antenna according to an exemplary embodiment of the disclosure in which a radio frequency resistor is shown;

FIG. 7 is a schematic view showing operations of the transmitting antenna shown in FIG. 1 and the receiving antenna shown in FIG. 4;

FIG. 8 is a schematic view showing a product capable of simultaneously implementing wireless power supply and wireless communication, according to an embodiment of the present disclosure;

FIG. 9 is a functional and structural block diagram of the product shown in FIG. 8;

FIG. 10 is a schematic perspective view of a transmitting antenna or a receiving antenna of the product shown in FIG. 9; and

FIG. 11 is a schematic view showing assembling of the antennas with coils.

DETAILED DESCRIPTION OF EMBODIMENTS

The technical solution of the disclosure will be described hereinafter in further detail with reference to the following embodiments, taken in conjunction with the accompanying drawings. In the specification, the same or similar reference numerals indicate the same or similar parts. The description of the embodiments of the disclosure hereinafter with reference to the accompanying drawings is intended to explain the general inventive concept of the disclosure and should not be construed as a limitation on the disclosure.

In addition, in the following detailed description, for the sake of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may also be practiced without these specific details. In other instances, well-known structures and devices are illustrated schematically in order to simplify the drawing.

According to a general concept of the present disclosure, there is provided a wireless power supply equipment comprising: a base comprising a wireless power supply transmitting coil and an antenna; a extension dock comprising a wireless power supply receiving coil, an antenna, and a connection interface; a rotation shaft being configured to pivotally connect the base and the extension dock; and an application device configured to be connected to the extension dock through the connection interface.

According to another general concept of the present disclosure, there is provided a wireless power supply product comprising: a base comprising a transmitting coil and an antenna; an extension dock comprising a receiving coil, an antenna, and a connection interface; a rotation shaft configured to pivotally connect connecting the base and the extension dock; and an application device connecting to the extension dock through the connection interface.

According to a yet another general concept of the present disclosure, there is provided a wireless communication product comprising: a base including a transmitting coil and an antenna; an extension dock including a receiving coil, an antenna, and a connection interface; a rotation shaft configured to pivotally connect the base and the extension dock, the extension dock being configured to be connected an application device through the connection interface.

According to a still another general concept of the present disclosure, there is provided a product capable of simultaneously implementing wireless power supply and wireless communication, the product comprising: a base including a transmitting coil and an antenna; an extension dock including a receiving coil, an antenna, and a connection interface; a rotation shaft configured to pivotally connect the base and the extension dock, the extension dock being configured to be connected an application unit through the connection interface.

According to a yet still another general concept of the present disclosure, there is provided an antenna comprising: a substrate; a first circular metal strip formed on a surface of the substrate; and a second circular metal strip formed on the other surface of the substrate. One end of the first circular metal strip is a feed end, and the other end is for connecting to one end of a radio frequency resistor. One end of the second circular metal strip is a ground end, and the other end is for connecting to the other end of the radio frequency resistor.

FIG. 8 is a schematic view showing a product capable of simultaneously implementing wireless power supply and wireless communication, according to an embodiment of the present disclosure. FIG. 9 is a functional and structural block diagram of the product shown in FIG. 8. FIG. 10 is a schematic perspective view of a transmitting coil or a receiving coil of the product shown in FIG. 9; and FIG. 11 is a schematic view showing assembling of the antennas with the coils.

In the illustrated embodiments, as shown in FIG. 8 to FIG. 11 , there is provided a product capable of simultaneously implementing wireless power supply and wireless communication. The product mainly includes a base, an extension dock and a replaceable audio/video device (audio or video device). The base includes a circular transmitting coil, a circular antenna, a power supply circuit and a communication circuit. The extension dock includes a circular receiving coil, a circular antenna, a power supply circuit and a communication circuit. The replaceable audio/video device may be a camera, a display, a human-machine interactive device, a billboard, a top radar of a driverless car, and the likes. The circular coils and the circular antennas of the base and the extension dock are respectively placed on a common rotation shaft. The circular coil has outer and inner rings wound in opposite directions so as to reduce an eddy current loss on the metal rotation shaft. The circular antenna is a near- field circularly polarized antenna that enables high-speed wireless short-range communication while reducing the impact of signal leakage on the surroundings.

In the illustrated embodiments, as shown in FIG. 8 to FIG. 11, the extension dock and the replaceable audio/ video device are wired and electrically connected, to form a combination without changing relative positions thereof. The combination is fixedly mounted to a metal cylinder passing through the center thereof. The metal cylinder also passes through the base. There is no physical contact between the base and the combination.

In the illustrated embodiment, as shown in FIG. 10, the transmitting coil and the receiving coil are formed respectively by connecting in series two co-planar and coaxially placed sub-coils. Since the winding directions of the inner and outer sub-coils are opposite to each other, the currents flowing through the inner and outer sub-coils are opposite in direction, such that, magnetic field generated by the currents are co-directionally superposed to have an increased magnetic field strength within an annular region between the two sub-coils, , and are reversely cancelled to have a decreased magnetic field strength within the sub-coil with a smaller diameter. As a result, the eddy current generated on the metal cylinder vertically passing through the inside of the sub-coil with the smaller diameter is smaller, and at the same time, if a metal object is placed outside of the sub-coil with a larger diameter, a eddy current generated on the metal object is also smaller.

In the shown embodiment, the structure of the receiving coil is the same as that of the transmitting coil, but the size of the receiving coil may be different from that of the transmitting coil. The shapes of the transmitting coil and the receiving coil are not limited to a circular shape, and may be any polygonal shape. A ferrite magnet may be placed on one side of the coil to enhance the coupling between the transmitting coil and the receiving coil.

In one embodiment of the present disclosure, simulations and experiments have demonstrated that a coil that comprises outer and inner rings wound in opposite directions can significantly reduce eddy current power on the metal object (including the rotation shaft and antennas, etc.) passing through the interior of the coil by at least 20%.

In the shown embodiment, as shown in FIG. 11, the antennas and the coils (e.g., the transmitting antenna 1 and the transmitting coil, the receiving antenna 2 and the receiving coil) are placed coaxially with each other, and their relative positions are relatively flexible. The antenna may have a smaller diameter so that it can be placed inside the coil, or may have a larger diameter so that it can be placed outside the coil.

FIG. 1 to FIG. 7 show embodiments of the antennas applied in the product shown in FIG. 8 and FIG. 9.

In the illustrated embodiments, as shown in FIG. 1 to FIG. 7, the antenna is consisted of two circular metal strips on a single-layer double-sided PCB. One ends of the two metal strips are feed ends of the antennas, and, in actual use, are connected to radio frequency ground and radio frequency pin of a radio frequency chip, and the other ends are connected to one radio frequency resistor, respectively. The two, upper and lower, circular metal strips are each formed into a mircostrip transmission line, and changing of a width of the metal strip may cause changing of the characteristic impedance of the microstrip transmission line. Output characteristic impedance of a commonly used radio frequency chip is 50 ohms, so the characteristic impedance of the microstrip transmission line and the terminated radio frequency resistor are both 50 ohms. Transmission lines having other impedance values are not excluded. The metal strip occupies almost the entire length of the circle, with only 1 to 5 mm discontinuities between two end faces thereof. The termination resistance is equal to the characteristic impedance of the transmission line, thus when the antenna is fed, the electromagnetic wave in the transmission line is a traveling wave flowing only in one direction, while, the conventional far-field antenna operates in a resonant state has an internal electromagnetic field in the form of standing wave. The antenna has a wider bandwidth similar as the transmission line, and the electric field around the circular traveling wave antenna is circularly polarized, and the polarization is not affected by its own rotation angle. Referring to FIG. 2, when two identical antennas are placed in parallel and close to each other (R«2D X (2/l)), the electromagnetic waves emitted by one of the antennas can be effectively received by the other of the antennas, and strength of the received signal is usually much larger than receiving sensitivity of the wireless chip. In addition, since the antenna is a near field antenna, and its far-field radiant energy is very low, it is very difficult to obtain a long distance signal interception.

The products shown in FIG. 8 to FIG. 11 can be products capable of simultaneously implementing wireless power supply and wireless communication. However, the present disclosure is not limited to this. The products shown in FIG. 8 to FIG. 11 can also be used as products for enabling wireless power supply only or products for enabling wireless communication only.

Specific structural features of the aforementioned antennas (e.g., the antenna 1 and the antenna 2) will be described in detail below with reference to FIG. 1 to FIG. 7. Embodiment of Transmitting Antenna

FIGS. 1 to 3 show a transmitting antenna 10 according to an exemplary embodiment of the disclosure. FIG. 1 shows a schematic perspective view of a transmitting antenna when viewed from the front according to an exemplary embodiment of the disclosure, and FIG. 2 shows a perspective view of the transmitting antenna when viewed from the back according to an exemplary embodiment of the disclosure.

As shown in FIGS. 1 and 2, in the illustrated embodiment, the transmitting antenna mainly comprises a substrate 100, a first circular metal strip 110 formed on one surface of the substrate 100, and a second circular metal strip 120 formed on the other surface of the substrate 100 opposite to the one surface.

FIG. 3 shows a schematic exploded perspective view of the transmitting antenna according to an exemplary embodiment of the disclosure in which a radio frequency resistor 130 is shown.

As shown in FIGS. 1 to 3, in the illustrated embodiment, the first circular metal strip 110 has one end 111 used as a feed end and the other end 112 adapted to be connected to one end of the radio frequency resistor 130. The second circular metal strip 120 has one end 121 used as a grounding terminal and the other end 122 adapted to be connected to the other end of the radio frequency resistor 130.

In practical application, the one end 111 of the first circular metal strip 110 is connected to a feed end of a radio frequency chip (not shown), and the one end 121 of the second circular metal strip 120 is connected to a grounding terminal of the radio frequency chip (not shown).

In an exemplary embodiment of the disclosure, the substrate 100 may comprise a circuit board, and the first circular metal strip 110 and the second circular metal strip 120 each may comprise a metal microstrip transmission line printed on the circuit board.

As shown in FIGS. 1 to 3, in the illustrated embodiment, a distance between the two ends 111, 112 of the first circular metal strip 110 is within a range of 1 mm to 5 mm. A distance between the two ends 121 and 122 of the second circular metal strip 120 is within a range of 1 mm to 5 mm.

As shown in FIGS. 1 to 3, in the illustrated embodiment, the circuit board 100 may have a circular or annular shape.

Embodiment of Receiving Antenna

FIGS. 4 to 6 show a receiving antenna 20 according to an exemplary embodiment of the disclosure. FIG. 4 shows a schematic perspective view of a receiving antenna when viewed from the front according to an exemplary embodiment of the disclosure, and FIG. 5 shows a schematic perspective view of the receiving antenna when viewed from the back according to the exemplary embodiment of the disclosure.

As shown in FIGS. 4 and 5, in the illustrated embodiment, the receiving antenna mainly comprises a substrate 200, a first circular metal strip 210 formed on one surface of the substrate 200 and a second shaped metal strip 220 formed on the other surface of the substrate 200 opposite to the one surface.

FIG. 6 shows a schematic exploded perspective view of the receiving antenna according to an exemplary embodiment of the disclosure in which a radio frequency resistor 230 is shown.

As shown in FIGS. 4 to 6, in the illustrated embodiment, the first circular metal strip 210 has one end 211 used as a feed end and the other end 212 adapted to be connected to one end of the radio frequency resistor 230. The second circular metal strip 220 has one end 221 used as a ground terminal and the other end 222 adapted to be connected to the other end of the radio frequency resistor 230.

In practical application, the one end 211 of the first circular metal strip 210 is connected to a feed end of a radio frequency chip (not shown), and the one end 221 of the second circular metal strip 220 is connected to a grounding terminal of the radio frequency chip.

In an exemplary embodiment of the disclosure, the substrate 200 may comprise a circuit board, and the first circular metal strip 210 and the second circular metal strip 220 may comprise metal microstrip transmission lines printed on the circuit board.

As shown in FIGS. 4 to 6, in the illustrated embodiment, a distance between the two ends 211, 212 of the first circular metal strip 210 is within a range of 1 mm to 5 mm. A distance between the two ends 221 and 222 of the second circular metal strip 220 is within a range of 1 mm to 5 mm.

As shown in FIGS. 4 to 6, in the illustrated embodiment, the above circuit board 200 may have a circular or annular shape.

Embodiment of Transmitting Device

In an exemplary embodiment of the disclosure, there is also provided a transmitting device mainly comprising a transmitting antenna, a radio frequency resistor and a radio frequency chip.

The transmitting antenna may comprise the transmitting antenna as shown in FIGS. 1 to 3. As shown in FIGS. 1 to 3, the transmitting antenna mainly comprises a substrate 100, a first circular metal strip 110 formed on one surface of the substrate 100, and a second circular metal strip 120 formed on the other surface of the substrate 100.

As shown in FIGS. 1 to 3, in the illustrated embodiment, the first circular metal strip 110 is connected to a feed end of a radio frequency chip (not shown) at one end 111 thereof, and the second circular metal strip 120 is connected to a grounding terminal of the radio frequency chip at one end 121 thereof. The first circular metal strip 110 is connected to one end of the radio frequency resistor 130 at the other end 112 thereof, and the second circular metal strip 120 is connected to the other end of the radio frequency resistor 130 at the other end 122 thereof. An impedance value of a characteristic impedance of each of the first circular metal strip 110 and the second circular metal strip 120 is substantially equal to a resistance value of the radio frequency resistor 130.

In an exemplary embodiment of the disclosure, the impedance value of the characteristic impedance of each of the first circular metal strip 110 and the second circular metal strip 120 may be within the range of 30 ohms to 70 ohms.

In another exemplary embodiment of the disclosure, the impedance value of the characteristic impedance of each of the first circular metal strip 110 and the second circular metal strip 120, and the resistor value of the radio frequency resistor 130 may be substantially equal to 50 ohms.

In an exemplary embodiment of the disclosure, the characteristic impedance of each of the first circular metal strip 110 and the second circular metal strip 120 may be changed by changing a width and/or thickness of each of the first circular metal strip 110 and the second circular metal strip 120.

As shown in FIGS. 1 to 3, in the illustrated embodiment, the substrate 100 may comprise a circuit board, and the first circular metal strip 110 and the second circular metal strip 120 may comprise metal microstrip transmission lines printed on the circuit board.

As shown in FIGS. 1 to 3, in the illustrated embodiment, a distance between the two ends 111, 112 of the first circular metal strip 110 is within a range of 1 mm to 5 mm. A distance between the two ends 121 and 122 of the second circular metal strip 120 is within a range of 1 mm to 5 mm.

Embodiment of Receiving Device

In an exemplary embodiment of the disclosure, there is also provided a receiving device mainly comprising a receiving antenna, a radio frequency resistor and a radio frequency chip.

The receiving antenna may comprise the receiving antenna as shown in FIGS. 4 to 6. As shown in FIGS. 4 to 6, the receiving antenna mainly comprises a substrate 200, a first circular metal strip 210 formed on one surface of the substrate 200, and a second circular metal strip

220 formed on the other surface of the substrate 200.

As shown in FIGS. 4 to 6, in the illustrated embodiment, one end 211 of the first circular metal strip 210 is connected to a feed end of a radio frequency chip (not shown), and one end

221 of the second circular metal strip 220 is connected to a grounding terminal of the radio frequency chip. The other end 212 of the first circular metal strip 210 is connected to one end of the radio frequency resistor 230, and the other end 222 of the second circular metal strip 220 is connected to the other end of the radio frequency resistor 230. An impedance value of the characteristic impedance of each of the first circular metal strip 210 and the second circular metal strip 220 is substantially equal to a resistance value of the radio frequency resistor 230.

In an exemplary embodiment of the disclosure, the impedance value of the characteristic impedance of each of the first circular metal strip 210 and the second circular metal strip 220 may be within the range of 30 ohms to 70 ohms.

In another exemplary embodiment of the disclosure, the impedance value of the characteristic impedance of each of the first circular metal strip 210 and the second circular metal strip 220, and the resistor value of the radio frequency resistor 230 may be substantially equal to 50 ohms.

In an exemplary embodiment of the disclosure, the characteristic impedance of each of the first circular metal strip 210 and the second circular metal strip 220 may be changed by changing a width and/or thickness of each of the first circular metal strip 210 and the second circular metal strip 220.

As shown in FIG. 4 to 6, in the illustrated embodiment, the substrate 200 may comprise a circuit board, and the first circular metal strip 210 and the second circular metal strip 220 may comprise metal microstrip transmission lines printed on the circuit board.

As shown in FIGS. 4 to 6, in the illustrated embodiment, a distance between the two ends 211, 212 of the first circular metal strip 210 is within a range of 1 mm to 5 mm. A distance between the two ends 221 and 222 of the second circular metal strip 220 is within a range of 1 mm to 5 mm.

Embodiment of Wireless Communication System

In an exemplary embodiment of the disclosure, there is also provided a wireless communication system mainly comprising the transmitting device and the receiving device as described above referring to FIGS. 1-6.

FIG. 7 shows a schematic view of the transmitting antenna 10 shown in FIG. 1 and the receiving antenna 20 shown in FIG. 4 in operation.

As shown in FIG. 7, in the illustrated embodiment, the transmitting antenna 10 and the receiving antenna 20 have a common central axis Z about which at least one of the transmitting antenna 10 and the receiving antenna 20 may be rotated.

As shown in FIG. 7, in the illustrated embodiment, the transmitting antenna and the receiving antenna may be rotated about the same central axis. When one of the transmitting antenna and the receiving antenna is rotated with respect to the other, the distance between the transmitting antenna and the receiving antenna will not be changed. Therefore, it is possible to ensure signal intensity and signal receiving quality without increasing transmission power. Moreover, since it does not need to increase the transmission power, far field radiation energy of the antenna is very low. In this way, it is possible to effectively prevent communication signals from being leaked into the surrounding environment and being eavesdropped by others, thereby improving safety and security of the communication.

In the above embodiments of the disclosure, any one of the transmitting antenna and the receiving antenna comprises a substrate and upper and lower circular metal strips formed on upper and lower surfaces of the substrate. Each circular metal strip occupies almost full length of a circle except a spacing of 1 to 5 mm being provided at the two end faces thereof The impedance value of the characteristic impedance of each of the circular metal strips are substantially equal to the resistance value of the radio-frequency resistors connected in series between them. Therefore, when feeding the antennas, an electromagnetic wave within each of the circular metal strips is a traveling wave only propagating in one direction, while the traditional far- field antenna may be operated in a resonant state, and the electromagnetic field therein is in the form of a standing wave. The antennas of the disclosure have a wide bandwidth similar to a transmission line, and the electric field around the circular traveling wave antenna is a circular polarization, and the polarization mode thereof is not affected by its own rotation angle. As shown in FIG. 7, when the two antennas are placed in parallel and close to each other at a coaxial distance (R«2D2/k]), the electromagnetic wave emitted by one antenna may be effectively received by the other. At the same time, since the antennas of the disclosure are near-field antennas, their far field radiation energy are very low, and it is very difficult to capture the signals at a long distance.

It should be appreciated by those skilled in this art that the above embodiments are intended to be illustrative, and many modifications may be made to the above embodiments by those skilled in this art, and various structures described in various embodiments may be freely combined with each other without conflicting in configuration or principle.

Although the disclosure have been described hereinbefore in detail with reference to the attached drawings, it should be appreciated that the disclosed embodiments in the attached drawings are intended to illustrate the preferred embodiments of the disclosure by way of example, and should not be construed as limitation to the disclosure.

Although several exemplary embodiments of the general concept of the disclosure have been shown and described, it would be appreciated by those skilled in the art that various changes or modifications may be made to these embodiments without departing from the principles and spirit of the disclosure, the scope of which is defined by the claims and their equivalents.

It should be noted that, the word“comprise” doesn’t exclude other elements or steps, and the word“a” or“an” doesn’t exclude more than one. In addition, any reference numerals in the claims should not be interpreted as the limitation to the scope of the disclosure.