Rectifier antenna and array suitable for long-distance microwave energy transmission

Abstract

The invention discloses a rectification antenna and array suitable for long-distance microwave energy transmission. The rectification antenna comprises four rectification antenna units, a power synthesis network and a DC load. The four rectification antenna units are the same in structure, each rectification antenna unit comprises a rectifier chip and an antipode linear tapered slot antenna which are connected, the antipode linear tapered slot antenna is used for receiving microwave energy from a free space and inputting the microwave energy to the rectifier chip, and the rectifier chip is used for converting the microwave energy into a direct current signal; the four rectification antenna units are connected with a direct current load through a power synthesis network to supply power to the direct current load; the power synthesis network is used for adjusting the series-parallel connection relation of the four rectification antenna units so as to adjust the output voltage and current for supplying power to the direct current load. Through an innovative PCB antenna-CMOS chip cascade and array scheme, the contradiction between efficiency and scale in long-distance transmission is solved, and the effects of low cost and high integration are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic circuit design, and particularly relates to a rectifying antenna and array suitable for long-distance microwave energy transmission. BACKGROUND

[0002] The goal of modern wireless communication systems is to provide stable and high-speed data link services to terminal users at any time and in any place. Through wireless energy transmission technology, near space vehicles such as unmanned aerial vehicles or floating platforms can realize automatic energy supply, which will cross the time and space limits and truly realize intelligent continuous work and long-term stable application in high-altitude auxiliary wireless communication. Wireless power transfer (WPT) technology is a technology based on non-conductive contact, which realizes the transmission of electric energy from the transmitting end to the receiving end (large-scale rectifying antenna array) in free space through microwave beams. It has the characteristics of charging at any time, no need to plug in, no electrical contact, safety and reliability, and supporting multiple devices to charge at the same time, so that the use of electrical equipment can be freed from the shackles of cables, greatly increasing the convenience and flexibility of power supply for electrical equipment. The working frequency of the WPT system needs to be balanced between system size and efficiency. The millimeter wave W band (75-110 GHz) is in the atmospheric attenuation window, and the loss is small. For antennas of the same physical aperture size, more energy can be collected by means of a narrow directional beam in a high-frequency working state, making it possible for millimeter wave wireless energy transmission technology to become a potential solution for power supply of near space vehicles and unmanned aerial vehicle communication base stations. It needs to be particularly emphasized that the rectifying antenna size in the WPT system needs to be large enough to intercept more than 90% of the energy of the main lobe of the transmitted beam to ensure the efficiency of the entire WPT system. Therefore, it is necessary to design a large-scale rectifying antenna array suitable for the millimeter wave frequency band.

[0003] For millimeter wave wireless energy transmission applications, the cost and efficiency of the millimeter wave rectifying antenna array will determine whether the WPT system can be used on a large scale. The core of this is to design a low-cost, high-efficiency, and fully integrated rectifying chip and antenna. At present, most millimeter wave rectifying chips are realized based on Schottky barrier diodes of III-V semiconductor process, which has relatively high cost and relatively large size. In the prior art, the direct current power synthesis efficiency between rectifying units is low, the array layout flexibility is poor, and the impedance mismatch problem is serious at high frequency, which restricts the improvement of the overall system efficiency.

[0004] Therefore, the research on a high-efficiency, low-cost rectifying antenna array working in the W band will become a key issue for the large-scale and long-term application of WPT technology in near space vehicles such as unmanned aerial vehicles or floating platforms, and also a key breakthrough in realizing wireless energy transmission in the millimeter wave frequency band. SUMMARY

[0005] Technical purposes: In view of the problems in the prior art, the application discloses a rectifier antenna and array suitable for long-distance microwave energy transmission, solves the contradiction between efficiency and scale in long-distance transmission through an innovative PCB antenna-CMOS chip cascade and array scheme, and achieves the effects of low cost and high integration.

[0006] Technical scheme: To achieve the above technical purposes, the application adopts the following technical scheme.

[0007] A rectifier antenna suitable for long-distance microwave energy transmission, comprising: a first rectifier antenna unit, a second rectifier antenna unit, a third rectifier antenna unit, a fourth rectifier antenna unit, a power synthesis network and a direct current load. The first rectifier antenna unit, the second rectifier antenna unit, the third rectifier antenna unit and the fourth rectifier antenna unit are of the same structure, each rectifier antenna unit comprises a connected rectifier chip and a pair of linearly tapered slot antennas, the pair of linearly tapered slot antennas are used for receiving microwave energy from free space and inputting the microwave energy to the rectifier chip, and the rectifier chip is used for converting the microwave energy into a direct current signal; the four rectifier antenna units are connected with the direct current load through the power synthesis network to realize power supply to the direct current load; and the power synthesis network is used for adjusting the series-parallel relationship of the four rectifier antenna units, and then adjusting the output voltage and current for the power supply to the direct current load.

[0008] Further, each rectifier antenna unit is of the same structure and is arranged on a PCB, comprises a groove, and the rectifier chip is arranged in the groove, the input end of the rectifier chip is connected with the antenna feeding port of the pair of linearly tapered slot antennas, and the output end of the rectifier chip is connected with the power synthesis network input port of the power synthesis network.

[0009] Further, the surface of the rectifier chip and the antenna feeding port are in the same plane.

[0010] Further, the rectifier chip comprises a balun and a differential rectification pair, the balun separates the radio frequency output from the ground, and simultaneously converts the single-ended signal V RFIN into the differential radio frequency signals V RFIN+ and V RFIN- , the differential signals are respectively injected into the gate and the drain of the rectification transistor of the differential rectification pair through a first-order LC network and a capacitor, and the rectified signal is output as a direct current output of the rectifier chip through an inductor.

[0011] Further, the structure of the rectifier chip comprises: The primary same end of the balun is used as the input end of the rectifier chip, and the input signal V RFINThe primary side of the balun is grounded; the secondary side of the balun outputs differential RF signals V at the same-name and different-name terminals respectively. RFIN+ and V RFIN- Differential radio frequency signal V RFIN+ The differential radio frequency signal V is connected to the drain of the first rectifier transistor through the first capacitor. RFIN+ The first capacitor and the first inductor are connected in series and then used as the output terminal of the rectifier chip, providing the differential radio frequency signal V. RFIN+ Grounded through a first-order LC network, the differential radio frequency signal V RFIN+ The differential radio frequency signal V is connected to the gate of the first rectifier transistor through a capacitor in the first-order LC network. RFIN- The differential radio frequency signal V is connected to the drain of the second rectifier transistor via the second capacitor. RFIN- The second capacitor and second inductor are connected in series to form the output terminal of the second rectifier chip, and the differential radio frequency signal V RFIN- Grounded via a second-order LC network, the differential radio frequency signal V RFIN- The capacitor in the second first-order LC network is connected to the gate of the second rectifier transistor; the source of the second rectifier transistor and the source of the first rectifier transistor are grounded; the output terminal of the rectifier chip outputs a signal V. DCOUT .

[0012] Furthermore, rectifier chips and antennas are used in the W band.

[0013] The present invention also discloses a rectifier antenna array suitable for long-distance microwave energy transmission, comprising a plurality of rectifier antennas as described above for long-distance microwave energy transmission, wherein the rectifier antennas are connected to a DC load through a power combining network, and the number of rectifier antenna elements is n*n, where n is an integer greater than 2.

[0014] Beneficial effects: 1. This invention effectively improves the power conversion efficiency and output DC power of the rectifier antenna through a novel rectifier antenna structure design; 2. For W-band signals, the rectifier chip can provide a power conversion efficiency of 45%, and the rectifier antenna and array as a whole can provide a power conversion efficiency of 20%. 3. The rectifier antenna technology proposed in this invention, which cascades a CMOS rectifier chip and a PCB receiving antenna, reduces costs by more than 40%. While achieving high rectification efficiency, it can be modularly assembled on a large scale to form a large-scale rectifier antenna array. Attached Figure Description

[0015] The accompanying drawings, which are provided to further illustrate embodiments of the invention and form part of this application, are not intended to limit the scope of the invention. Figure 1 This is a schematic diagram of a 2*2 rectifier antenna structure suitable for long-distance microwave energy transmission according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the interconnection between the antenna and the rectifier chip using gold wire bonding, according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the rectifier chip structure according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the simulation results of the PCB pole-coupled linear tapered slot antenna according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the actual test results of a 2*2 rectifier antenna suitable for long-distance microwave energy transmission according to an embodiment of the present invention; Figure 6 This is a physical diagram of a 16-unit modular rectifier antenna array suitable for long-distance microwave energy transmission according to an embodiment of the present invention; Figure 7 This is a schematic diagram of a large-scale long-distance microwave energy transmission system according to an embodiment of the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0017] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0018] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0019] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0020] In the description of this application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Example

[0021] As attached Figure 1 As shown, a rectifier antenna suitable for long-distance microwave energy transmission in this embodiment includes: a first rectifier antenna unit 102, a second rectifier antenna unit 104, a third rectifier antenna unit 106, a fourth rectifier antenna unit 108, a power combining network 110, and a DC load 112. The first rectifier antenna unit 102, the second rectifier antenna unit 104, the third rectifier antenna unit 106, and the fourth rectifier antenna unit 108 have the same structure. Each rectifier antenna unit includes a connected rectifier chip 204 and a pole-coupled linear taper slot antenna 116. The pole-coupled linear taper slot antenna 116 is used to receive W-band microwave energy from free space and input it to the rectifier chip 204. The rectifier chip 204 is used to convert the W-band microwave energy into a DC signal. The four rectifier antenna units are connected to a DC load 112 through a power combining network 110 to power the DC load. The power combining network 110 is used to adjust the series and parallel connection relationship of the four rectifier antenna units, thereby adjusting the output voltage and current for powering the DC load. When the rectifier antenna units are connected in series, the output voltage doubles; when connected in parallel, the output current doubles. The specific connection relationship is set according to the actual situation.

[0022] This invention achieves large-scale series and parallel connection of rectifier antenna units through power combining network 110, which enables flexible adjustment of DC output voltage and current to meet the power requirements of various DC loads.

[0023] In this embodiment, the connection method of the power combining network 110 includes: the input terminal of the first rectifier antenna unit 102 is connected to the output terminal of the third rectifier antenna unit 106, the input terminal of the third rectifier antenna unit 106 is grounded to the input terminal of the fourth rectifier antenna unit 108, the output terminal of the fourth rectifier antenna unit 108 is connected to the input terminal of the second rectifier antenna unit 104, and the output terminals of the second rectifier antenna unit 104 and the first rectifier antenna unit 102 are both connected to one end of the DC load 112, and the other end of the DC load 112 is grounded.

[0024] All four rectifier antenna units utilize W-band polarized linear tapered slot antennas manufactured using printed circuit board technology to receive free-space microwave energy. The microwave / millimeter-wave energy is then converted into DC power by a W-band rectifier chip manufactured using CMOS technology. This DC power is then connected via a power combining network 110 and output to a DC load 112. Testing has verified that this 2x2 rectifier antenna unit configuration provides a power conversion efficiency of over 25% in the W-band.

[0025] Each rectifier antenna unit has an identical structure and is mounted on a PCB, including a recess 202. A rectifier chip 204 is housed within the recess 202. The input terminal of the rectifier chip 204 is connected to the antenna feed port 206 of the pole-coupled linear tapered slot antenna 116, and the output terminal of the rectifier chip 204 is connected to the power combining network input port 212 of the power combining network 110. The surface of the rectifier chip 204 and the antenna feed port 206 are on the same plane, minimizing the length of the gold wire bonding wires used to connect the antenna and the chip, thus minimizing the cascading loss between the antenna and the chip. Generally, the feed terminal of a PCB pole-coupled linear tapered slot antenna is located on the PCB surface. The height of the rectifier chip in the W-band is approximately 300µm, and the overall height difference between the chip and the antenna is over 300µm, resulting in a gold wire bonding wire length exceeding 400µm and a cascading loss between the antenna and the chip exceeding 5dB. This invention innovatively proposes an antenna-chip cascading technology, such as... Figure 2 As shown, grooves are artificially created on the PCB and the rectifier chip is mounted in the grooves to ensure that the chip surface and the antenna are on the same plane. This makes the length of the gold wire bonding wire less than 80um and the cascade loss less than 1dB, which greatly reduces the length of the gold wire bonding wire and the cascade loss between the antenna and the chip.

[0026] It should be noted that the cascaded design of the antenna and chip in this invention greatly reduces the cascade loss between the antenna and the chip. For example... Figure 2As shown, a recess 202 with a depth of approximately 300µm is fabricated on the PCB, and the rectifier chip 204 is mounted in the recess, ensuring that the chip surface and the antenna feed port 206 are on the same plane. The chip 204 and the antenna feed port 206 are connected by gold wire bonding wire 208. The length of the gold wire bonding wire 208 is less than 80µm, much smaller than the conventional 400µm length. The DC output of the chip is connected to the power combining network input port 212 via gold wire bonding wire 210.

[0027] The rectifier chip includes a balun 300 and a differential rectifier pair. The balun 300 uses a vertically coupled topology to separate the RF output from ground, while converting the single-ended signal V... RFIN Converted to differential radio frequency signal V RFIN+ and V RFIN- The differential signal is injected into the gate and drain of the rectifier transistors of the differential rectifier pair through a first-order LC network and a capacitor, respectively. The rectified signal is then used as the DC output of the rectifier chip through an inductor. The capacitor is used to avoid DC coupling, the first-order LC network is used for input matching to minimize input loss, and the inductor is used for RF choke and DC output. This chip is designed using a 40nm CMOS process and has a chip size of 0.0252mm. 2 .

[0028] Figure 3 This is a structural diagram of the rectifier chip of the present invention. The rectifier chip is a millimeter-wave rectifier chip, i.e., a differential rectifier chip, and its structure includes: The primary side of the balun 300 serves as the input terminal of the rectifier chip 204, connected to the input signal V. RFIN The primary side of the balun 300 is grounded; the secondary side of the balun 300 outputs differential radio frequency signals V at the same-name and different-name terminals respectively. RFIN+ and V RFIN- Differential radio frequency signal V RFIN+ The differential radio frequency signal V is connected to the drain of the first rectifier transistor 331 through the first capacitor 301. RFIN+ The first capacitor 301 and the first inductor 311 are connected in series and then used as the output terminal of the rectifier chip 204, which is the differential radio frequency signal V. RFIN+ Grounded via the first-order LC network 321, differential RF signal V RFIN+ The differential radio frequency signal V is connected to the gate of the first rectifier transistor 331 through the capacitor in the first-order LC network 321. RFIN- The differential radio frequency signal V is connected to the drain of the second rectifier transistor 332 through the second capacitor 302. RFIN- The second capacitor 302 and the second inductor 312 are connected in series and then used as the output terminal of the second rectifier chip 204, providing the differential radio frequency signal V. RFIN-Grounded via a second-order LC network 322, differential RF signal V RFIN- The capacitor in the second first-order LC network 322 is connected to the gate of the second rectifier transistor 332; the source of the second rectifier transistor 332 and the source of the first rectifier transistor 331 are grounded; the output terminal of the rectifier chip 204 outputs a signal V. DCOUT Among them, capacitors 301 and 302 are used to avoid DC coupling, first-order LC networks 321 and 322 are used for input matching to minimize input loss, and inductors 311 and 312 are used as RF chokes and DC outputs.

[0029] It should be noted that, although the switching rectifier chip in this invention is like... Figure 3 As shown, however, other millimeter-wave rectifier chips and their connection methods with antennas are also feasible, and will not be elaborated here.

[0030] This embodiment also discloses a rectifier antenna array suitable for long-distance microwave energy transmission, comprising several rectifier antennas as described above. The rectifier antennas are connected to a DC load via a power combining network, and the number of rectifier antenna elements is n*n, where n is an integer greater than 2. For example, a 16-element modular rectifier antenna array can be implemented, comprising 16 identical rectifier antenna elements. Each rectifier antenna element includes a PCB polarity linear tapered slot antenna and a W-band rectifier chip manufactured using CMOS technology, with the antenna and chip connected via gold wire bonding for radio frequency connection. This module can be expanded to large-scale arrays, such as 16*16 and 64*64 arrays. Through modular design, it allows for flexible array configuration and the ability to replace failed modules at any time, avoiding large-scale array failures caused by problems with a single module.

[0031] Figure 4 This is a simulation structure of the antenna gain and radiation pattern of the epipolar linear tapered slot antenna of the present invention. Due to the unique structure of the two gradually tapering metals on both sides of the substrate, the antenna has the characteristics of narrow beamwidth, high component gain, and wide bandwidth. Simulation results show that the antenna gain is higher than 13.5 dBi in the 91 to 100 GHz range. The symmetry of the antenna radiation is also very good when φ equals 90°, where φ represents the angle between the z-axis surface and the x-axis.

[0032] Figure 5 The actual test results of the 2*2 rectifier antenna array proposed in this invention are presented. At a transmission distance of 30cm and an incident power density of 90mW / cm², the conversion efficiency of this 2*2 rectifier antenna array can reach up to 23%, with an output DC voltage of 1.2V and a DC power of 20.6mW.

[0033] Figure 6The 16-element modular rectifier antenna array proposed in this invention comprises 16 identical rectifier antenna elements and a power combining network. Through flexible series-parallel array configurations (parallel configuration with constant voltage and doubled current, series configuration with constant current and doubled voltage), large-scale rectifier antenna arrays, such as a 1024-element array, can be formed. This allows for flexible adjustment of output voltage and current, adapting to the power requirements of various DC loads. It enables the construction of long-distance, high-efficiency, high-power, and low-cost millimeter-wave wireless power transmission systems, such as… Figure 7 As shown.

[0034] This invention utilizes advanced CMOS technology to research high-efficiency, low-cost, fully integrated millimeter-wave rectifier chips and high-efficiency millimeter-wave receiving antennas using high-frequency PCB technology. Ultimately, it achieves large-scale, high-efficiency, and low-cost millimeter-wave rectifier antenna arrays, possessing significant academic research value and high practical value. Furthermore, the structure proposed in this invention is universally applicable, not only to W-band rectifier antenna designs but also to rectifier antenna array designs in other millimeter-wave frequency bands. For example, by replacing the W-band antenna and rectifier chip with those of other corresponding frequency bands, it can be applied to other millimeter-wave frequency bands. This invention provides an additional solution for powering future long-term deployed spacecraft.

[0035] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0036] It will be apparent to those skilled in the art that this application is not limited to the details of the exemplary embodiments described above, and that this application can be implemented in other specific forms without departing from the spirit or essential characteristics of this application. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this application is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this application. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A rectifier antenna suitable for long-distance microwave energy transmission, characterized in that, include: The system comprises a first rectifier antenna unit, a second rectifier antenna unit, a third rectifier antenna unit, a fourth rectifier antenna unit, a power combining network, and a DC load. The first, second, third, and fourth rectifier antenna units have the same structure. Each rectifier antenna unit includes a connected rectifier chip and a pole-coupled linear tapered slot antenna. The pole-coupled linear tapered slot antenna is used to receive microwave energy from free space and input it to the rectifier chip. The rectifier chip is used to convert the microwave energy into a DC signal. The four rectifier antenna units are connected to a DC load through a power combining network to power the DC load. The power combining network is used to adjust the series and parallel connection relationship of the four rectifier antenna units, thereby adjusting the output voltage and current for powering the DC load.

2. A rectifier antenna suitable for long-distance microwave energy transmission according to claim 1, characterized in that: Each rectifier antenna unit has the same structure and is mounted on the PCB. It includes a recess containing a rectifier chip. The input terminal of the rectifier chip is connected to the antenna feed port of the pole linear tapered slot antenna, and the output terminal of the rectifier chip is connected to the power combining network input port of the power combining network.

3. A rectifier antenna suitable for long-distance microwave energy transmission according to claim 2, characterized in that, The surface of the rectifier chip is on the same plane as the antenna feed port.

4. A rectifier antenna suitable for long-distance microwave energy transmission according to claim 1, characterized in that, The rectifier chip includes a balun and a differential rectifier pair. The balun separates the RF output from ground while converting the single-ended signal V... RFIN Converted to differential radio frequency signal V RFIN+ and V RFIN- The differential signal is injected into the gate and drain of the rectifier transistor of the differential rectifier pair through a first-order LC network and a capacitor, respectively. The rectified signal is used as the DC output of the rectifier chip through an inductor.

5. A rectifier antenna suitable for long-distance microwave energy transmission according to claim 4, characterized in that: The structure of the rectifier chip includes: The primary side terminal of the balun serves as the input terminal of the rectifier chip, connected to the input signal V. RFIN The primary side of the balun is grounded; the secondary side of the balun outputs differential RF signals V at the same-name and different-name terminals respectively. RFIN+ and V RFIN- Differential radio frequency signal V RFIN+ The differential radio frequency signal V is connected to the drain of the first rectifier transistor through the first capacitor. RFIN+ The first capacitor and the first inductor are connected in series and then used as the output terminal of the rectifier chip, providing the differential radio frequency signal V. RFIN+ Grounded through a first-order LC network, the differential radio frequency signal V RFIN+ The differential radio frequency signal V is connected to the gate of the first rectifier transistor through a capacitor in the first-order LC network. RFIN- The differential radio frequency signal V is connected to the drain of the second rectifier transistor via the second capacitor. RFIN- The second capacitor and second inductor are connected in series to form the output terminal of the second rectifier chip, and the differential radio frequency signal V RFIN- Grounded via a second-order LC network, the differential radio frequency signal V RFIN- The capacitor in the second first-order LC network is connected to the gate of the second rectifier transistor; the source of the second rectifier transistor and the source of the first rectifier transistor are grounded; the output terminal of the rectifier chip outputs a signal V. DCOUT .

6. A rectifier antenna suitable for long-distance microwave energy transmission according to claim 1, characterized in that: The rectifier chip and antenna are used in the W band.

7. A rectifier antenna array suitable for long-distance microwave energy transmission, characterized in that, It includes several rectifier antennas as described in any one of claims 1-6, which are suitable for long-distance microwave energy transmission. The rectifier antennas are connected to a DC load through a power combining network, and the number of rectifier antenna elements is n*n, where n is an integer greater than 2.

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