Method for extracting guide beacons in long-distance high-capacity microwave power transmission system

Abstract

The invention relates to a method for extracting a guide beacon in a long-distance high-power microwave power transmission system, and belongs to the field of microwave communication. According to the method, the problem that in a long-distance high-power microwave power transmission system, at least 160dB transmitting-receiving isolation is needed to extract a guide beacon is solved by using a dispersion-independence-convergence method; the ultra-large index of 160dB is dispersed to the dual-frequency antenna, the amplitude phase cancellation module and the receiving band-pass filter to independently complete the distributed indexes, and then the indexes are organically converged by the electronic circuit to jointly realize the transmitting-receiving isolation of at least 160db. The amplitude phase cancellation module is arranged between the dual-frequency antenna high-power transmitting end and the weak guide signal receiving end; the dual-frequency antenna comprises a parabolic reflecting surface, a metal tube mounted on the central line of the reflecting surface, and two sets of orthogonally polarized oscillators with different frequencies, which are fixed on the metal tube. According to the invention, the problem of difficult extraction of the guide beacons in the DIC-ASPS system is solved.

Description

Technical Field

[0001] The invention belongs to the field of microwave communication and relates to a method for extracting a guide beacon in a long-distance and large-capacity microwave power transmission system. Background Art

[0002] The long-distance, large-capacity microwave power transmission system has been proposed by Yang Shizhong at the 717th Xiangshan Science Conference, the 8th Wireless Energy Transmission and Energy Interconnection Technology Forum, Chongqing Daily and many other places. It is often used in the microwave transmission system of the decentralized, independent and convergent space solar power station (DIC-ASPS), such as the patent with publication number CN 113890204 A, a microwave power transmission system for a space solar power station. The basic principle of DIC-ASPS is already popular science knowledge, see Section 2.3.5.1 of the "White Paper on Solar Power Satellites". After the basic principle of DIC-ASPS was made public, many units tried to implement a demonstration and verification model of DIC-ASPS, but no one has achieved it so far except Yang Shizhong's team. The bottleneck of realizing DIC-ASPS lies in the extraction of the guidance beacon. The transmission power of the DIC-ASPS unit is in the order of KW (60dbm), and the receiving beacon is in the order of -90dbm, with a difference of 150db (10 15 times). The strong transmission power entering the beacon receiver will block or burn it. In addition, the signal-to-noise ratio of the guidance beacon extraction circuit needs to be greater than 10db. In this way, the isolation should be greater than 160db. To this end, domestic and foreign counterparts have done a lot of work, but none of them are ideal or suitable for the air-space solar power station (ASPS). See the following five existing technical solutions:

[0003] Solution 1: Some people abroad use two separate antennas to transmit strong power and receive weak beacons respectively, see Figure 1 Three isolation measures are adopted: ① polarization isolation, the strong power is transmitted horizontally, and the weak beacon is received vertically; ② spatial isolation, the transmitting and receiving antennas are separated by a certain distance in space; ③ frequency isolation, the transmitting frequency is f o The receiving frequency is f PILOT The three isolation measures can achieve a total isolation of 50db (105 times), see Figure 1 The problems are: ① Although 50db isolation is the best transmit-receive isolation we have found, it is still far from meeting the 160db isolation requirement; ② Spatial isolation, the transmit and receive antennas are separated by a certain distance in space, which will inevitably lead to guidance distance errors; ③ Double the number of antennas will inevitably lead to complex spatial structure (the antenna array is the bulk of the structure).

[0004] Solution 2: Energy Conversion and Transmission Modules for Space Solar Power By Paul Jaffe, Member IEEE, and James McSpadden, Senior Member IEEE, Fig. 2.3-3 proposed a guidance beacon extraction scheme, see Figure 2 This solution is similar to Solution 1, and adopts: ① spatial isolation, the transmitting and receiving antennas are separated by a certain distance in space; ② frequency isolation, the receiving frequency is ω1 and the transmitting frequency is 2ω1, but polarization isolation is not used. Therefore, its isolation is worse than Solution 1, and the three problems of Solution 1 still exist here.

[0005] Solution 3: Report of the URSI Inter-Commission Working Group on SPS, Chinese version of "Solar Power Satellite White Paper", Section 2.3.5.1 introduces Retrodirective arry. Figure 3 , the following two guidance beacon extraction schemes are disclosed:

[0006] (1) See Figure 3 (a), the problems are: ① two guide beacons are used, which makes the guide beacon transceiver system complicated; ② a single antenna is used for transmission and reception in the same frequency band, and the transmission and reception isolation is completed by a continuous wave duplexer. It is known that the transmission and reception isolation of a continuous wave duplexer is less than 30db, which is far from meeting the 160db isolation requirement.

[0007] (2) See Figure 3 (b) The problems are: ① The use of two guidance beacons makes the beacon transceiver system complex; ② The transmitting and receiving antennas are separated in space, resulting in position guidance errors; ③ The three antennas make the antenna array space structure more complex (the antenna array is the bulk of the structure); ④ Polarization isolation is possible, but this is not mentioned in the data.

[0008] Solution 4: Patent No. CN111262604A discloses a beam self-tracking full-duplex communication system and method based on directional backtracking antenna. The problems are: ① The transmitting and receiving antenna arrays are separated in space, resulting in position guidance errors. ② The isolation of the transmitting and receiving antenna arrays can only be improved by increasing the distance. This in turn increases the position error. Therefore, this solution is only applicable to communication systems with low transmission power.

[0009] Solution 5: "Research on microwave transmission energy beam pointing control technology based on phase conjugation", Chen Yanlong, "China Excellent Master's Degree Thesis Full-text Database" Engineering Technology II (Monthly), 2019 Issue 04, 2019-03-16-2019-04-15 Published, C042-763. See the paper Figure 5 .4, the problem is: ① The pilot signal and the energy signal are both 2.9GHz, so the antenna should be a co-frequency antenna, not a dual-frequency antenna. ② The antenna has only one feed source, and the pilot signal and the energy signal are both added to one feed port. The energy signal must be coupled to the receiving end in large quantities, causing the receiving amplifier to be blocked or burned. ③ If this feed port is said to be a circulator. The circulator is a single-frequency device and cannot be used for dual-frequency antennas. Even if it is used for single-frequency antennas, its isolation is only less than 30db. ④ Figure 5 .4 is wrong. The 2.9GHz in the figure should be 5.8GHz after the multiplier, not 2.9GHz. Summary of the invention

[0010] In view of this, the purpose of the present invention is to provide a method for extracting a guide beacon in a long-distance, large-capacity microwave power transmission system to solve the problem of ultra-high (>160db) transmission-reception isolation of the power transmission-reception system, thereby solving the problem of difficulty in extracting the guide beacon in the DIC-ASPS system.

[0011] In order to achieve the above object, the present invention provides the following technical solutions:

[0012] A method for extracting a guidance beacon in a long-distance, large-capacity microwave power transmission system, wherein the microwave power transmission subsystem receives a 2.9GHz input signal using a dual-frequency antenna, and after filtering through a bandpass filter (BPF), mixes the signal emitted by a 5.8GHz frequency source through a first mixer, and then passes through a first amplifier, a second mixer (frequency multiplier), a second amplifier, and a bandpass amplifier (BPA) in sequence, and finally obtains a 5.8GHz frequency-doubled conjugate amplified signal, which is emitted through a dual-frequency antenna. The method is characterized in that an amplitude phase cancellation module is provided in the microwave power transmission subsystem, which is arranged between the high-power transmitting end (5.8GH) of the dual-frequency antenna and the weak guidance signal receiving end (2.9GH), and is integrated with the dual-frequency antenna and the input bandpass filter to achieve a transmission-reception isolation of at least 160db.

[0013] Furthermore, the dual-frequency antenna is used to achieve an isolation of at least 30db; the dual-frequency antenna includes a parabolic reflector, a metal tube installed on the center line of the reflector, and two sets of vibrators fixed on the metal tube; the reflector flips the radiation directions of the two sets of vibrators with orthogonal polarizations by 180 degrees; the two sets of vibrators are orthogonally placed at appropriate positions of the metal tube (i.e., slid to the maximum gain position);

[0014] Each set of oscillators includes an active oscillator and a reflective oscillator; the active oscillator is fixed on the metal tube through an insulator and connected to the feeder; the reflective oscillator is in direct contact with the metal tube.

[0015] Furthermore, the length of the reflective oscillator is between 0.5 and 0.55 wavelengths; the length of the active oscillator is 0.5 wavelengths; and the distance between the active oscillator and the reflective oscillator is between 0.15 and 0.23 wavelengths.

[0016] Furthermore, the two active oscillators are respectively connected to the receiving end and the transmitting end on the back side of the parabola reflector through a symmetrical balanced feeder or a balanced-to-unbalanced converter.

[0017] Furthermore, the amplitude phase cancellation module (AP module) includes an upper coupler, a lower coupler, an attenuator and a phase shifter; the amplitude phase cancellation module achieves an isolation of at least 60db by adjusting the attenuator and the phase shifter;

[0018] The 5.8GHz high-power microwave output by the bandpass amplifier (BPA) enters the bandpass filter (BPF) through the upper coupler, attenuator, phase shifter and lower coupler, and is called the cancellation signal; the amplitude and phase of the cancellation signal are adjusted to make them equal in amplitude and opposite in phase to the transmitting and receiving interference signals; they cancel each other at the bandpass filter (BPF).

[0019] Furthermore, the bandpass filter (BPF) indicators are: the center frequency is 2.9GHz, the insertion loss is <1dB, and the attenuation of the transmission frequency 5.8GHz is >70db. This is a common microwave component, and the processing and customization are also very cheap.

[0020] The beneficial effect of the present invention is that the present invention organically distributes the transmit-receive isolation index of greater than 160db required by the microwave transmission system in the DIC-ASPS to various parts of the system (e.g., dual-frequency antenna>30dB, amplitude phase cancellation module>60dB, bandpass filter BPF>70dB), each part is processed independently, and then they are organically gathered by electronic circuits to jointly achieve at least 160db transmit-receive isolation.

[0021] The specific advantages of each part are as follows:

[0022] (1) The dual-frequency antenna designed in the present invention adds a parabolic reflector surface to flip the radiation direction by 180 degrees, thereby narrowing the beam and improving the gain. In addition, the two sets of oscillators of the dual-frequency antenna of the present invention are orthogonally placed, polarized orthogonally, and have little mutual influence. The structure is simple and compact, which is convenient for super-multiple element arrays, such as 10,000-element arrays.

[0023] (2) The amplitude phase cancellation module designed in the present invention can attenuate the transmission and reception crosstalk by at least 60db by adjusting the attenuator and the phase shifter.

[0024] (3) The bandpass filter BPF index proposed by the present invention is reasonable, which reduces the processing cost.

[0025] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0027] Figure 1 The schematic diagram of using two separate antennas to transmit strong power and receive weak beacons in the existing solution 1;

[0028] Figure 2 Schematic diagram of the guidance beacon extraction scheme designed for two spatially separated antennas in the existing scheme 2;

[0029] Figure 3 Schematic diagram of two guidance beacon extraction schemes listed in the existing scheme 3;

[0030] Figure 4 This is a schematic diagram of the high-isolation system for transmitting and receiving proposed by the present invention;

[0031] Figure 5 It is a schematic diagram of the dual-frequency antenna structure of the present invention;

[0032] Figure 6 This is a schematic diagram of the amplitude phase cancellation module of the present invention;

[0033] Figure 7 To experimentally verify the technical effect of the method of the present invention. DETAILED DESCRIPTION

[0034] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0035] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0036] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0037] See also Figures 4 to 7 The present invention provides a method for extracting a guide beacon in a long-distance, large-capacity microwave power transmission system, which organically disperses the transmit-receive isolation index greater than 160db to various parts of the system, processes each part independently, and converges (i.e., the DIC idea) to solve the large index of "160db transmit-receive isolation". Figure 4 This is a schematic diagram of the integrated innovation system of the present invention, and an example of the allocation of the transmit-receive isolation index is as follows: the amplitude phase cancellation module is 60db; the dual-frequency antenna is 30db; the band-pass filter BPF is 70db.

[0038] (1) Dual-band antenna

[0039] There are many types of dual-band antennas, designed and used as needed. Figure 5 It is a schematic diagram of the dual-frequency antenna structure. The dual-frequency antenna designed by the present invention adds a parabolic reflector, flips the radiation direction of two sets of orthogonal polarization vibrators (each set contains a source vibrator and a reflector) by 180 degrees, and places them on the center line of the reflector. The reflector can ensure the unidirectional radiation of the antenna. According to the known Yagi vibrator antenna design: the reflector is in direct contact with the metal tube. The active vibrator is insulated from the metal tube and connected to the feeder. The length of the reflector is between 0.5 and 0.55 wavelengths, and its length cannot be less than 1 / 2 wavelength corresponding to the corresponding frequency. The length of the active vibrator is 0.5 wavelength; the distance between the active vibrator and the reflector is between 0.15 and 0.23 wavelengths. The two sets of vibrators are orthogonally placed at the appropriate position of the metal tube (i.e., sliding to the maximum gain), with orthogonal polarization, little mutual influence, simple and compact structure, and convenient for super-multiple arrays, such as 10,000-unit arrays.

[0040] (2) Amplitude Phase Cancellation Module (AP Module)

[0041] There are many types of AP modules, which are designed and used as needed. The mobile communication system MC and the fixed space solar power station ASPS have different requirements, use different AP modules, have different requirements for transmit and receive isolation, and have different interference properties to be eliminated (MC has low transmission power, so the transmit and receive interference is not serious, but multiple access interference, multiplicative noise, additive noise, Doppler frequency shift... are serious. ASPS is a high-power transmission between fixed points, without the various noise problems of MC. The only interference is the interference of the super-strong transmission power to the receiver). The schematic diagram of the AP module of this technology is as follows Figure 6 As shown in the dotted box. The 5.8GHz high-power microwave output by the bandpass amplifier BPA passes through the upper coupler, attenuator, phase shifter to the lower coupler and enters the bandpass filter BPF, and is called the cancellation signal. Adjust the amplitude and phase of the cancellation signal to make it equal to the amplitude and opposite to the phase of the transmission and reception interference signal. Cancel each other at the bandpass filter BPF. The attenuator and phase shifter here are ordinary microwave components. Adjusting the attenuator and phase shifter can attenuate the transmission and reception interference by 60db. Provide at least 60db isolation for the system.

[0042] (3) Bandpass filter BPF

[0043] Basic indicators of bandpass filter BPF: center frequency is 2.9GHz, bandwidth is 2MHz, and attenuation at 5.8GHz of stop band is 70db. This is a common microwave component, and processing and customization are also very cheap.

[0044] The above three methods of improving the transmission and reception isolation are all existing technologies. A single technology cannot solve the problem of ultra-high (>160db) transmission and reception isolation of the power transmission and reception system. The present invention integrates many existing technologies and its own thinking to form an integrated innovation, solves the problem of extracting the guidance beacon in the DIC-ASPS system, and makes the DIC-ASPS demonstration and verification model successful and enters engineering.

[0045] Experimental verification:

[0046] Ultra-high transmit / receive isolation (>160db) ensures the extraction of the guidance beacon and the power beam is directed to the center of the ground receiving aperture. Figure 7 As shown in the figure, when there is wind, the antenna array suspended in the air moves with the wind. However, the power beam tracks the guidance beacon, and the received power remains unchanged; in addition, when 4 units are intentionally destroyed, the DIC still works normally, with only a 12 / 16 reduction in power.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for extracting a guidance beacon in a long-distance, large-capacity microwave power transmission system, wherein: The microwave power transmission subsystem utilizes a dual-frequency antenna to receive a 2.9GHz input signal, which is filtered by a bandpass filter and then mixed with a 5.8GHz frequency source output signal through a first mixer, and then sequentially passes through a first amplifier, a second mixer, a second amplifier, and a bandpass amplifier to finally obtain a 5.8GHz frequency-doubled conjugate amplified signal, which is then transmitted through a dual-frequency antenna. The microwave power transmission subsystem is characterized in that an amplitude-phase cancellation module is provided in the microwave power transmission subsystem, which is arranged between a high-power transmitting end of the dual-frequency antenna and a weak guidance signal receiving end, and is integrated with the dual-frequency antenna and the input bandpass filter to achieve a transmit-receive isolation of at least 160db.

2. The method for extracting a guidance beacon according to claim 1, characterized in that: The dual-frequency antenna is used to achieve an isolation degree of at least 30db; the dual-frequency antenna includes a parabolic reflector, a metal tube installed on the center line of the reflector, and two sets of vibrators fixed on the metal tube; the reflector flips the radiation directions of the two sets of vibrators with orthogonal polarizations by 180 degrees; the two sets of vibrators are orthogonally placed on the metal tube and slide to the maximum gain; Each set of oscillators includes an active oscillator and a reflective oscillator; the active oscillator is fixed on the metal tube through an insulator and connected to the feeder; the reflective oscillator is in direct contact with the metal tube.

3. The method for extracting a guidance beacon according to claim 2, characterized in that: The length of the reflective oscillator is between 0.5 and 0.55 wavelengths; the distance between the active oscillator and the reflective oscillator is between 0.15 and 0.23 wavelengths.

4. The method for extracting a guidance beacon according to claim 2, characterized in that: The two active oscillators are respectively connected to a receiving end and a transmitting end on the back side of the parabola reflector through a symmetrical balanced feeder or a balanced-to-unbalanced converter.

5. The method for extracting a guidance beacon according to claim 1, characterized in that: The amplitude phase cancellation module includes an upper coupler, a lower coupler, an attenuator and a phase shifter; the amplitude phase cancellation module achieves an isolation of at least 60db by adjusting the attenuator and the phase shifter; The 5.8GHz high-power microwave output by the bandpass amplifier enters the bandpass filter through the upper coupler, attenuator, phase shifter to the lower coupler and is called the cancellation signal; the amplitude and phase of the cancellation signal are adjusted to make the amplitude equal to the amplitude of the transmitting and receiving interference signals and the phase opposite; they cancel each other at the bandpass filter.

6. The method for extracting a guidance beacon according to claim 1, characterized in that: The input bandpass filter has a high attenuation of at least 70 dB for the transmit frequency.

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