Remote high-power microwave power transmission system guide beacon zero intermediate frequency extraction method

Abstract

The application provides a long-distance high-power microwave power transmission system guide beacon zero intermediate frequency extraction method, which comprises the following steps: S1, taking a central array element of a phased array as a central reference array element, and receiving a guide beacon by a double-frequency antenna of each array element, and then performing band-pass filtering and band-pass amplification, and then performing frequency mixing with a reference signal; S2, performing low-pass filtering on two mixed output signals respectively, filtering out high-frequency terms, and obtaining in-phase components and quadrature components; using an operational amplifier circuit to take the inverse of the quadrature components at a baseband, and obtaining the inverse quadrature components; S3, multiplying the quadrature components with in-phase reference signals and quadrature reference signals respectively, and feeding the phase conjugate signals after the multiplication into a double-frequency antenna transmitting end after passing through a frequency multiplier and a 2 times frequency band-pass amplifier, and then transmitting, so as to realize power beam backtracking to the direction of the guide beacon. The zero intermediate frequency extraction circuits of the array elements are arranged in a multi-channel parallel mode, and the method is suitable for large-scale phased arrays.

Description

Technical Field

[0001] This invention relates to the field of microwave power transmission, and in particular to a method for extracting the zero intermediate frequency of a guiding beacon in a long-distance high-power microwave power transmission system. Background Technology

[0002] Among existing space-based solar power station solutions, there is a distributed-independence-converged aerospace solar power station scheme, namely the DIC-ASPS scheme, where DIC stands for Disperse Independence Convergence and ASPS stands for Aerospace Solar Power Station. This scheme involves long-distance, high-capacity continuous wireless power transmission technology. Its microwave power transmission relies on a beamback array: a guiding beacon is set up, and each array element extracts the phase information of the guiding beacon and transmits a phase-conjugate power beam, causing the power beam to automatically backtrack and point towards the guiding beacon.

[0003] The basic principles of DIC-ASPS have been published, but its engineering implementation faces difficulties. Microwave power transmission in space-based solar power stations requires large-scale phased arrays. Due to the limited power of individual power amplifiers, each array element needs to employ microwave power combining technology.

[0004] The bottleneck in implementing the above scheme lies in the extraction of the guide beacon signal. The unit's transmit power is on the order of kW, or 60dBm, while the received guide beacon signal level is on the order of -90dBm, a difference of 150dB, or 10 to the power of 15. The powerful transmit power entering the guide beacon signal receiver will cause the receiver to be blocked or damaged. The guide beacon signal extraction circuit needs a signal-to-noise ratio greater than 10dB, therefore the transmit-receive isolation should be greater than 150dB plus 10dB, or 160dB.

[0005] To address the aforementioned transmission-receiver isolation issue, the applicant has previously filed an invention patent application with publication number CN119995707A entitled "Method for Extracting Guiding Beacons in Long-Distance High-Capacity Microwave Power Transmission Systems." This prior application distributes the 160dB transmission-receiver isolation requirement across a dual-band antenna, an amplitude-phase cancellation module, and an input bandpass filter. Each component independently fulfills its assigned requirement, which is then integrated using electronic circuitry to achieve at least 160dB of transmission-receiver isolation: the dual-band antenna provides at least 30dB isolation, the amplitude-phase cancellation module provides at least 60dB isolation, and the bandpass filter provides greater than 70dB attenuation at the transmission frequency.

[0006] However, the ground demonstration system implemented according to the prior application only has 16 array elements, and the transceiver circuits of the array elements are all analog microwave circuits. The conjugation processing is completed in the microwave frequency band, resulting in large size and weight, making it difficult to integrate into a chip. It is difficult to realize a large-scale space phased array using this technology. Therefore, a method for zero intermediate frequency extraction of the guiding beacon is needed to move the conjugation processing to the baseband. Summary of the Invention

[0007] This invention aims to at least solve the technical problems existing in the prior art, and particularly innovatively proposes a zero-IF extraction method for guiding beacons in long-distance high-power microwave power transmission systems. Building upon the at least 160dB transmit / receive isolation already achieved in a previous application, the invention employs zero-IF technology to move the conjugate processing to the baseband, facilitating the chip-based integration of array element transceiver circuits and thus supporting the engineering implementation of large-scale space phased arrays.

[0008] To achieve the above-mentioned objectives of the present invention, the present invention provides a method for zero-IF extraction of a guiding beacon in a long-distance high-power microwave power transmission system, comprising the following steps:

[0009] S1, using the central element of the phased array as the central reference element, it is determined that the phase of the guiding beacon signal it receives is 0; the dual-band antennas of the remaining elements receive the guiding beacon signal, one of which is mixed with the output of the bandpass amplifier (m) and the output of the bandpass amplifier (middle), and the other is mixed with the output of the bandpass amplifier (m) and the output of the bandpass amplifier (middle) after a 90-degree phase shift, with the mixing difference frequency component falling in the baseband; the bandpass amplifier (middle) is one signal of the central reference element;

[0010] S2, perform low-pass filtering on the two mixer outputs respectively to filter out the high-frequency terms generated by mixing, retaining only the baseband components to obtain the in-phase components. Orthogonal components , The phase difference between the m-th received guiding beacon signal and the central reference array element is given. The in-phase and quadrature components are stored as two analog voltages to preserve the relative phase of the corresponding array elements. The quadrature components are inverted in the baseband using an operational amplifier circuit to obtain the inverted quadrature components. The in-phase and inverted quadrature components together constitute the conjugate complex components. , The imaginary unit enables relative phase reversal;

[0011] S3 multiplies the in-phase component with the in-phase reference signal, and multiplies the inverted quadrature component with the quadrature reference signal. The two products are added together by an adder. The combined signal is converted into a phase conjugate transmit signal by frequency doubling and bandpass amplification. The phase conjugate transmit signal is fed into the transmitter of the dual-frequency antenna and transmitted. The frequencies of the in-phase reference signal and the quadrature reference signal are the same as the frequency of the guiding beacon signal, so that the power beam can be traced back to the direction of the guiding beacon signal.

[0012] In the preferred embodiment of the above technical solution, S1 includes: selecting the geometric center element of the phased array as the central reference element, using the output of the received guidance beacon signal after bandpass amplification as the phase reference of the entire array and determining its phase to be 0, and comparing the phase of each of the other array elements with the central reference element, and the resulting phases are all relative to the central reference element.

[0013] In the preferred embodiment of the above technical solution, the in-phase reference signal in S1 is the output of the guiding beacon signal received by the central reference array element after bandpass amplification, and the quadrature reference signal is obtained by phase shifting the output by a 90-degree phase shifter. The in-phase reference signal and the quadrature reference signal have the same frequency, equal amplitude, and orthogonal phases.

[0014] In the preferred embodiment of the above technical solution, the low-pass filter in S2 filters out the 2-harmonic term generated by mixing, retaining only the baseband component. The resulting in-phase component is represented as the cosine of the relative phase of the corresponding array element, and the resulting quadrature component is represented as the inverse of the sine of the relative phase of the corresponding array element.

[0015] In the preferred embodiment of the above technical solution, the conjugation in S2 is performed by an operational amplifier circuit in the baseband. The in-phase component remains unchanged after being directly passed through, while the quadrature component is amplified by the operational amplifier circuit to obtain the inverted quadrature component. The in-phase component and the inverted quadrature component together constitute the conjugated complex component.

[0016] In the preferred embodiment of the above technical solution, one input of the S3 adder is the product of the in-phase component and the in-phase reference signal, and the other input is the product of the inverted quadrature component and the quadrature reference signal. The adder adds the two products together, and the frequency of the combined signal is the same as the frequency of the guiding beacon signal. Its relative phase is equal in magnitude and opposite in sign to the relative phase of the received guiding beacon signal.

[0017] In the preferred embodiment of the above technical solution, the frequency of the S1 guiding beacon signal is 2.9 GHz, and the frequency multiplication is 2 times the frequency multiplication. The 2.9 GHz signal synthesized by the adder with the relative phase inverted is transformed into a 5.8 GHz signal, which is then amplified by bandpass to suppress spurious emissions and increase power, resulting in a 5.8 GHz phase conjugate transmission signal, which is fed into the 5.8 GHz transmitter of the dual-frequency antenna.

[0018] In the preferred embodiment of the above technical solution, the S1 dual-frequency antenna includes a parabolic reflector, a metal tube mounted on the center line of the reflector, and two sets of vibrators fixed on the metal tube. The two sets of vibrators operate at a 2.9 GHz receiving frequency and a 5.8 GHz transmitting frequency, respectively, and their polarizations are orthogonal to each other. The receiving vibrator is connected to the receiving end of the guiding beacon signal, and the transmitting vibrator is connected to the transmitting end of the phase conjugate transmitting signal.

[0019] The preferred embodiment of the above technical solution further includes an amplitude and phase cancellation module, which is disposed between the high-power transmitting end of the dual-band antenna and the receiving end of the guiding beacon signal. The sampled signal is coupled from the transmitted signal by a coupler, and the amplitude and phase of the sampled signal are adjusted by an attenuator and a phase shifter so that they are equal in amplitude and opposite in phase with the crosstalk signal, thus canceling each other out. The dual-band antenna provides at least 30dB isolation, the amplitude and phase cancellation module provides at least 60dB isolation, and the bandpass filter provides attenuation of more than 70dB for the transmitted frequency. The amplitude and phase cancellation module, together with the dual-band antenna and the bandpass filter, achieve at least 160dB of transmit and receive isolation.

[0020] In the preferred embodiment of the above technical solution, the center frequency of the S1 bandpass filter is 2.9 GHz, the insertion loss is less than 1 dB, and the attenuation for the 5.8 GHz transmission frequency is greater than 70 dB. The zero-IF extraction circuits for the remaining array elements are configured in parallel with multiple paths, each sharing the same in-phase reference signal and quadrature reference signal provided by the same central reference array element. This solution eliminates the need for a local oscillator synthesizer. Therefore, this application achieves a unified phase reference for the entire array by sharing a central reference signal, thereby extending its applicability to large-scale array element arrays.

[0021] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0022] Based on the already achieved at least 160dB transmit / receive isolation, the phase conjugation is shifted from the microwave band to the baseband and completed by the operational amplifier, making the array element transceiver circuit easier to chip-based; the zero intermediate frequency extraction circuits of the remaining array elements are set up in parallel with multiple channels, and each channel shares the same in-phase reference signal and quadrature reference signal provided by the same central reference array element, which facilitates expansion to large-scale array element arrays.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0025] Figure 1 This is a schematic diagram showing the phase comparison between the central reference array element and the other array elements in this invention.

[0026] Figure 2 This is a schematic diagram showing the phase comparison between one of the bandpass amplifiers (m) and the central reference array element in this invention;

[0027] Figure 3 This is a flowchart of the zero-IF guiding beacon extraction method of the present invention. Detailed Implementation

[0028] The embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention. Furthermore, only the phase and frequency at each point are analyzed. The absolute value of the amplitude is set to 1 and is not included in the analysis (in reality, it is related to the amplitude gain of each component), and should not be construed as a limitation of the present invention.

[0029] The following examples only analyze the phase and frequency at each point. To facilitate the explanation of the phase relationship, the absolute value of the amplitude is normalized to 1. The actual amplitude is determined by the gain of each component, and this normalization does not constitute a limitation on the actual link gain and output power.

[0030] The technical solution of this application can be used to expand and realize large-scale spatial phased arrays. The solution uses zero-IF technology to move the conjugation processing to the baseband, further enabling chip-based implementation. The zero-IF extraction circuits for the remaining array elements are configured in parallel with multiple channels, each sharing the same in-phase and quadrature reference signals provided by the same central reference element. For example... Figure 1 As shown, the central element of the phased array is used as a reference, and its phase is determined to be zero. The phases of the other elements are compared with the central element to obtain their phases relative to the central element.

[0031] The guiding beacon signal in this application originates from the difference frequency baseband component retained after low-pass filtering of the product of the tested guiding beacon signal, the in-phase reference signal, and the quadrature reference signal. The in-phase component and the quadrature component carry cosine and sine information of the relative phase, respectively, and the phase information is explicitly stored in the form of two analog voltages. DC offset suppression and DC operating point control are standard engineering design considerations for zero-IF mixers, low-pass filters, and operational amplifiers.

[0032] This application utilizes in-phase and quadrature reference signals provided by the central reference array element to complete zero-IF phase extraction, and then uses an operational amplifier in the baseband to invert the phase and reconstruct the phase-conjugate transmitted signal. Figures 1 to 3 As shown, this invention discloses a method for zero-IF extraction of a guiding beacon in a long-distance high-power microwave power transmission system, comprising the following steps:

[0033] This invention provides a method for zero-IF extraction of a guiding beacon in a long-distance, high-power microwave power transmission system, comprising the following steps:

[0034] S1: Taking the central array element of the phased array as the central reference array element, the phase of its received guidance beacon signal is defined as 0; the dual-frequency antennas of the remaining array elements receive the guidance beacon signal, where one path performs frequency mixing on the output of bandpass amplification (m) and the output of bandpass amplification (central), and the other path performs frequency mixing on the output of bandpass amplification (m) and the output obtained by subjecting the output of bandpass amplification (central) to 90-degree phase shifting, so that the difference frequency component after frequency mixing falls into the baseband; the bandpass amplification (central) refers to one path of signal from the central reference array element;

[0035] S2: The two frequency-mixed outputs are respectively subjected to low-pass filtering to filter out the high-frequency terms generated by frequency mixing, and only the baseband component is retained to obtain the in-phase component and the quadrature component , which is the phase difference of the guidance beacon signal received by the m-th path relative to the central reference array element; the in-phase component and the quadrature component store the relative phase of the corresponding array element in the form of two paths of analog voltages; an operational amplifier circuit is used at the baseband to invert the quadrature component to obtain an inverted quadrature component, and the in-phase component and the inverted quadrature component together form a conjugate complex component , which is the imaginary unit, to realize relative phase flipping;

[0036] S3: Multiply the in-phase component by the in-phase reference signal, multiply the inverted quadrature component by the quadrature reference signal, and sum the two products through an adder for synthesis; the synthesized signal is transformed into a phase-conjugate transmit signal via frequency doubling and bandpass amplification, and the phase-conjugate transmit signal is fed into the transmitting end of the dual-frequency antenna for transmission. The frequencies of the in-phase reference signal and the quadrature reference signal are the same as the frequency of the guidance beacon signal, so that the power beam is steered back towards the direction of arrival of the guidance beacon signal.

[0037] The definitions of each symbol in the present invention are as follows: the array is provided with a total of n paths, one of which is the central reference path, that is, the central reference array element, marked as "central", and any of the remaining paths is denoted as the m-th path, where m takes numbers from 1 to n excluding the number of the central reference path; the phase difference of the guidance beacon signal received by the m-th path relative to the central reference path is denoted as ; the in-phase component of the zero-intermediate-frequency baseband signal of the m-th path is denoted as , and the quadrature component is denoted as ; the complex baseband signal is represented by , and the conjugate complex component is represented by ; is the imaginary unit, satisfying , which is used to identify the corresponding quadrature branch, and the quadrature reference signal corresponding to this quadrature branch is obtained by subjecting the in-phase reference signal to 90-degree phase shifting; the frequency of the received guidance beacon signal is , and the transmit power frequency is .

[0038] The signal in the bandpass amplifier is one of the central reference array elements; the output signal in the bandpass amplifier is mixed with the output signal of bandpass amplifier 1 or bandpass amplifier n respectively.

[0039] like Figure 1 As shown in the figure, the bandpass amplified (1) or (m) signal on the left side of the figure passes through a double mixer, which is... Figure 2 The first and second mixers, located at the top left and bottom left of center X, are graphically represented after processing complex baseband signals. and conjugate complex components ; and then Figure 1 The double mixer on the right side is specifically... Figure 2 The diagram shows the 3rd and 4th mixers (top right and bottom right of the center X) and the adder. The pilot beacon signal frequency of the dual-band antenna is... Connect the signal input terminal of the bandpass amplifier (1), and use an operational amplifier circuit in the baseband to invert the quadrature component to obtain the inverted quadrature component. The in-phase component and the inverted quadrature component together constitute the conjugate complex component. The output transmit power frequency after 2 times bandpass amplification Similarly, a closed loop of dual-frequency antenna is set up in the bandpass amplifier (middle) of the circuit, and the bandpass amplifier (1) and bandpass amplifier (n) are mixed with the bandpass amplifier (middle) respectively.

[0040] Figure 2 The four mixers (also known as multipliers) located at the top left, bottom left, top right, and bottom right positions in the diagram are X, ... and its quadrature reference signal after 90-degree phase shift Inv is an inverter, constructed from an operational amplifier, with its input being... The output is .

[0041] Based on the above definition, the signal flow of the m-th path is described by the following set of formulas:

[0042] Bandpass amplification (m), output is: Bandpass amplification (medium), output is: The output of the 90-degree phase shifter is: .

[0043] The top left corner of X represents the first mixer. After low-pass filtering to remove the 2f1 frequency term, the result is... .

[0044] The second mixer is located at the bottom left of X. After low-pass filtering to remove the 2f1 frequency term, the result is... .

[0045] I nv For inverter output: That is, the orthogonal components after taking the inversion.

[0046] The top right corner of X represents the third mixer, and its output is: ;

[0047] The bottom right of X is the output of the 4th mixer: .

[0048] The adder is input from the third mixer. ;

[0049] The adder is input from the 4th mixer. ;

[0050] Adder output: ;

[0051] Substitution , ;

[0052] have to ;

[0053] Frequency multiplier output: .

[0054] The above formula is used to clarify the phase-frequency relationship of phase extraction, conjugate reconstruction, and frequency doubling backtracking of the guiding beacon signal. The technical solution of this application is to extract the relative phase of the guiding beacon signal and generate the phase conjugate transmitted signal, with the transmission beam direction determined by the relative phase of the transmitted signals of each array element.

[0055] The physical meaning of the above formula is: bandpass amplification (m), its output... This represents the guide beacon signal received by the m-th array element and amplified after bandpass filtering. Determined by the direction of the incoming wave and the geometric position of the array elements, this is all the spatial information that must be extracted for beam tracing; this signal serves as the first mixer in the upper left of X and the second mixer in the lower left of X. The measured input of the two mixers is the information source of the entire causal chain, serving as the input side of the signal.

[0056] Bandpass amplifier (medium), its output The phase of the center reference path is defined as the zero-phase reference. One path is directly used as the in-phase local oscillator, and the other path is converted to a 90-degree phase shifter. As a quadrature local oscillator, the two local oscillator frequencies are exactly the same as the received signal, belonging to a zero intermediate frequency architecture, so that the mixing difference frequency component falls exactly in the baseband, eliminating the need for intermediate frequency filtering and local oscillator synthesizer, creating conditions for realizing chip-based architecture.

[0057] The first mixer in the upper left of X uses a multiplication mixing operation in the in-phase branch, which is a product-to-sum-to-difference operation. The product contains a DC term. After low-pass filtering with the second harmonic and frequency term, we get ; Shifting the phase information parasitic on the 2.9 GHz carrier to zero frequency is the in-phase material for subsequent conjugation and reconstruction of the transmitted signal.

[0058] The second mixer at the bottom left of X uses a multiplication mixing operation in the quadrature branch, and after low-pass filtering, the quadrature components are obtained. ; and Synthetic complex baseband signal Phase information is stored in the form of two real-valued analog voltages. Used for identification The quadrature reference signal corresponding to the quadrature branch is obtained by 90-degree phase shift of the in-phase reference signal, which is then directly processed by the operational amplifier to complete the important step of converting the relative phase of the array elements into baseband in-phase and quadrature components.

[0059] I nv For inverter output This is the implementation of baseband conjugation: the complex baseband is composed of... Become ; The imaginary unit, in physical terms, means that the in-phase component Im remains unchanged and the quadrature component... The conjugation is achieved by inverting the op-amp; using only one op-amp to invert the conjugation completes the process, avoiding the complex conjugation circuitry in the radio frequency segment. This is the core benefit of moving the conjugation processing to the baseband and facilitating chip-level integration.

[0060] The third mixer on the upper right of X and the fourth mixer on the lower right of X multiply the baseband components by the in-phase carrier and the quadrature carrier, respectively, which is called quadrature upconversion. Their function is to transfer the phase information stored in the baseband back to the 2.9GHz radio frequency. The two outputs are used as the inputs of the adder.

[0061] Adder output The conjugate signal of the received beacon phase is reconstructed at 2.9 GHz, and this signal is used as the input of the frequency multiplier, whose phase -θm will be doubled during frequency multiplication.

[0062] Frequency multiplier output The frequency doubles to 5.8GHz, and the phase doubles to... Because the phase accumulated by the spatial path difference at 5.8 GHz is exactly twice that at 2.9 GHz, The returned signal is preset This exactly cancels out the signal, and the waves emitted by each array element are superimposed in phase at the guiding beacon signal, completing the beam direction backtracking in the sense of phase conjugation.

[0063] The dual-band antenna includes a parabolic reflector, a metal tube mounted on the center line of the reflector, and two sets of elements fixed on the metal tube. The two sets of elements operate at a 2.9 GHz receiving frequency and a 5.8 GHz transmitting frequency, respectively, and their polarizations are orthogonal. The dual-band antenna provides at least 30 dB of isolation. Each set of elements includes an active element and a reflector. The active element is fixed to the metal tube by an insulator and connected to a feed line. The reflector is in direct contact with the metal tube. The length of the reflector is between 0.5 and 0.55 wavelengths, the length of the active element is 0.5 wavelengths, and the distance between the active element and the reflector is between 0.15 and 0.23 wavelengths.

[0064] The invention also includes an amplitude and phase cancellation module, which is located between the high-power transmitting end of the dual-band antenna and the receiving end of the guiding beacon signal. The module includes an upper coupler, a lower coupler, an attenuator, and a phase shifter. The 5.8 GHz high-power microwave output from the bandpass amplifier passes through the upper coupler, attenuator, and phase shifter to the lower coupler and enters the bandpass filter, which is called the cancellation signal. The amplitude and phase of the cancellation signal are adjusted so that they are equal in amplitude and opposite in phase to the crosstalk signal, so that they cancel each other out at the bandpass filter, providing at least 60 dB of isolation.

[0065] The bandpass filter described in this invention has a center frequency of 2.9 GHz, a bandwidth of 2 MHz, an insertion loss of less than 1 dB, and an attenuation of more than 70 dB for the 5.8 GHz transmission frequency.

[0066] The phase error measured at the receiver at 2.9 GHz is amplified by a factor of two when transmitted at 5.8 GHz. This frequency doubling, which doubles the phase, is the necessary mechanism for beamback in this invention. The adder output signal reconstructs the conjugate signal of the receiving guide beacon signal phase at 2.9 GHz, and the frequency multiplier output frequency is doubled to 5.8 GHz, while the phase is also doubled. Because the phase accumulated by the spatial path at 5.8 GHz is twice that at 2.9 GHz, the preset phase of the transmitted signal... The phase of the spatial path cancels out, and the waves emitted by each array element are superimposed in phase at the guiding beacon signal.

[0067] The high-power transmit signal isolation scheme is fully documented from five aspects: demand derivation, specification allocation, antenna structure, cancellation module, and filter parameters. First, the unit transmit power is on the order of kW (60dBm), while the received guiding beacon signal level is on the order of -90dBm, a difference of 150dB. The guiding beacon signal extraction circuit needs a signal-to-noise ratio greater than 10dB; therefore, the transmit / receive isolation should reach at least 160dB. Second, this at least 160dB transmit / receive isolation is allocated as follows: at least 30dB for the dual-band antenna, at least 60dB for the amplitude and phase cancellation module, and at least 70dB for the bandpass filter.

[0068] Furthermore, the two sets of elements in the dual-band antenna operate at a 2.9 GHz receiving frequency and a 5.8 GHz transmitting frequency, respectively, with orthogonal polarizations. The active element, the reflector, and their dimensional relationships are given. Amplitude and phase cancellation includes an upper coupler, a lower coupler, an attenuator, and a phase shifter. By adjusting the amplitude and phase of the cancellation signal, it is made to have the same amplitude and opposite phase as the crosstalk signal, thus canceling each other out at the bandpass filter. The bandpass filter has a center frequency of 2.9 GHz, a bandwidth of 2 MHz, an insertion loss of less than 1 dB, and an attenuation of more than 70 dB at the 5.8 GHz transmitting frequency.

[0069] The above content has provided specific technical means and indicator allocation for achieving at least 160dB transmit / receive isolation.

[0070] For the common error of the reference signal itself, since all other array elements are phase-compared with the same central reference array element, and all channels share the in-phase reference signal and quadrature reference signal provided by the same central reference array element, this type of error is manifested as the common modulus of the entire array and does not change the relative phase relationship between the array elements.

[0071] like Figure 3 As shown, the present invention discloses a method for zero-IF extraction of a guiding beacon in a long-distance high-power microwave power transmission system, comprising the following steps: using the central element of the phased array as the central reference element, and determining that the phase of the guiding beacon signal received by it is zero; the dual-frequency antennas of the remaining array elements receive the guiding beacon signal, and after bandpass amplification, perform zero-IF orthogonal mixing, and after low-pass filtering, obtain in-phase orthogonal components, which are then combined through baseband conjugation to form conjugate complex components, and then synthesized by upconversion and bandpass amplification to realize the backtracking of the dual-frequency antenna transmit power beam toward the direction of the guiding beacon signal.

[0072] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for zero-IF extraction of a guiding beacon in a long-distance, high-power microwave power transmission system, characterized in that, Includes the following steps: S1, using the central element of the phased array as the central reference element, it is determined that the phase of the guiding beacon signal received by it is 0; the dual-band antennas of the remaining elements receive the guiding beacon signal, one of which is mixed with the output of bandpass amplifier m and the output of bandpass amplifier in the middle, and the other is mixed with the output of bandpass amplifier m and the output of bandpass amplifier after 90-degree phase shift, and the mixing difference frequency component falls in the baseband; the signal of the central reference element is in the middle of the bandpass amplifier. S2, perform low-pass filtering on the two mixer outputs respectively to filter out the high-frequency terms generated by mixing, retaining only the baseband components to obtain the in-phase components. Orthogonal components , The phase difference between the m-th received guiding beacon signal and the central reference path; the in-phase and quadrature components are stored in the form of two analog voltages to preserve the relative phase of the corresponding array elements; The quadrature components are inverted using an operational amplifier circuit in the baseband, resulting in inverted quadrature components. The in-phase components and the inverted quadrature components together form a conjugate complex component. , The imaginary unit enables relative phase reversal; S3 multiplies the in-phase component with the in-phase reference signal, and multiplies the inverted quadrature component with the quadrature reference signal. The two products are added together by an adder. The combined signal is converted into a phase conjugate transmit signal by frequency doubling and bandpass amplification. The phase conjugate transmit signal is fed into the transmitter of the dual-frequency antenna and transmitted. The frequencies of the in-phase reference signal and the quadrature reference signal are the same as the frequency of the guiding beacon signal, so that the power beam can be traced back to the direction of the guiding beacon signal.

2. The method for zero-IF extraction of a guiding beacon in a long-distance high-power microwave power transmission system according to claim 1, characterized in that, S1 includes selecting the geometric center element of the phased array as the central reference element, using the output of the received guidance beacon signal after bandpass amplification as the phase reference of the entire array and determining its phase to be 0, and comparing the phase of each of the other array elements with the central reference element, and the resulting phases are all relative to the central reference element.

3. The method for zero-IF extraction of a guiding beacon in a long-distance high-power microwave power transmission system according to claim 1, characterized in that, In S1, the in-phase reference signal is the output of the guide beacon signal received by the central reference array element after bandpass amplification. The quadrature reference signal is obtained by phase shifting the output by a 90-degree phase shifter. The in-phase reference signal and the quadrature reference signal have the same frequency, equal amplitude, and orthogonal phases.

4. The method for zero-IF extraction of a guiding beacon in a long-distance high-power microwave power transmission system according to claim 1, characterized in that, The low-pass filter in S2 filters out the 2-harmonic term generated by mixing, retaining only the baseband component. The resulting in-phase component is represented by the cosine of the relative phase of the corresponding array element, and the resulting quadrature component is represented by the inversion of the sine of the relative phase of the corresponding array element.

5. The method for zero-IF extraction of a guiding beacon in a long-distance high-power microwave power transmission system according to claim 4, characterized in that, In S2, the conjugation is performed in the baseband by an operational amplifier circuit. The in-phase component remains unchanged after being directly passed through, while the quadrature component is amplified by the operational amplifier circuit to obtain the inverted quadrature component. The in-phase component and the inverted quadrature component together constitute the conjugated complex component.

6. The method for zero-IF extraction of a guiding beacon in a long-distance high-power microwave power transmission system according to claim 5, characterized in that, The frequency of the synthesized signal synthesized by the adder in S3 is the same as the frequency of the guiding beacon signal, and its relative phase is equal in magnitude but opposite in sign to the relative phase of the received guiding beacon signal.

7. The method for zero-IF extraction of a guiding beacon in a long-distance high-power microwave power transmission system according to claim 1, characterized in that, The S1 guiding beacon signal frequency is 2.9GHz, and the frequency multiplication is 2 times the frequency multiplication. The 2.9GHz signal with the relative phase inverted synthesized by the adder is transformed into a 5.8GHz signal, which is then amplified by bandpass to suppress spurious emissions and increase power, resulting in a 5.8GHz phase conjugate transmit signal, which is fed into the 5.8GHz transmitter of the dual-frequency antenna.

8. The method for zero-IF extraction of a guiding beacon in a long-distance high-power microwave power transmission system according to claim 7, characterized in that, The S1 dual-frequency antenna includes a parabolic reflector, a metal tube mounted on the center line of the reflector, and two sets of vibrators fixed on the metal tube. The two sets of vibrators operate at a 2.9 GHz receiving frequency and a 5.8 GHz transmitting frequency, respectively, and their polarizations are orthogonal to each other. The receiving vibrator is connected to the receiving end of the guiding beacon signal, and the transmitting vibrator is connected to the transmitting end of the phase conjugate transmitting signal.

9. The method for zero-IF extraction of a guiding beacon in a long-distance high-power microwave power transmission system according to claim 1, characterized in that, It also includes an amplitude and phase cancellation module, which is located between the high-power transmitting end of the dual-band antenna and the receiving end of the guiding beacon signal. The sampled signal is coupled from the transmitted signal by a coupler, and the amplitude and phase of the sampled signal are adjusted by an attenuator and a phase shifter so that it is equal in amplitude and opposite in phase with the crosstalk signal, thus canceling each other out. The dual-band antenna provides at least 30dB isolation, the amplitude and phase cancellation module provides at least 60dB isolation, and the bandpass filter provides attenuation of more than 70dB for the transmitted frequency. The amplitude and phase cancellation module, together with the dual-band antenna and the bandpass filter, achieve at least 160dB of transmit and receive isolation.

10. The method for zero-IF extraction of a guiding beacon in a long-distance high-power microwave power transmission system according to claim 1, characterized in that, The S1 bandpass filter has a center frequency of 2.9 GHz, an insertion loss of less than 1 dB, and an attenuation of more than 70 dB for the 5.8 GHz transmission frequency. The zero intermediate frequency extraction circuits of the other array elements are set in parallel with multiple channels, and each channel shares the in-phase reference signal and quadrature reference signal provided by the same central reference array element.

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