A multi-channel transceiver microwave link structure and a method for generating a time-domain cover signal

Abstract

The present invention discloses a multi-channel transceiver microwave link structure and a method for generating a time-domain cover signal, belonging to the technical field of multi-channel transceiver microwave links, and solving the problem that there are a large number of cross branches in the existing microwave switch matrix, resulting in too many printed circuit board layers and poor feasibility. The multi-channel transceiver microwave link structure includes 4 groups of independent frequency conversion channels and a signal distribution network; the signal distribution network includes a 2×4 microwave switch matrix, and the switch matrix is divided into a first part and a second part. The first part is composed of an independent first 1-to-4 power divider module and a second 1-to-4 power divider module, and the circuit board surfaces of the first 1-to-4 power divider module and the second 1-to-4 power divider module are both placed horizontally; the second part is composed of 4 independent 2-to-1 switch modules, and the circuit board surfaces of the 2-to-1 switch modules are both placed vertically. The multi-channel transceiver microwave link structure overcomes the technical problems caused by the existence of cross branches.

Description

Technical Field

[0001] The present invention belongs to the technical field of multi-channel transceiver microwave link structures, and particularly relates to a multi-channel transceiver microwave link structure and a method for generating a time-domain cover signal. Background Art

[0002] With the development of technology, in the design of new multi-channel radar systems in recent years, the required independent frequency conversion chains have been expanded from 2 channels to 4 channels. Therefore, it is necessary to provide 4 frequency conversion local oscillator signals LO1, LO2, LO3, and LO4 that can be of the same frequency or different frequencies. At the same time, the operating frequency of the new radar has been expanded, requiring that the operating frequencies of the LO1, LO2, LO3, and LO4 signals reach the Ka band at the highest. Summary of the Invention

[0003] In view of the above analysis, the present invention aims to provide a multi-channel transceiver microwave link structure and a method for generating a time-domain cover signal to solve the following technical problems: There are a large number of cross branches in the microwave switch matrix of the existing multi-channel transceiver microwave link structure, resulting in too many printed circuit board layers and being infeasible in actual engineering.

[0004] The object of the present invention is mainly achieved through the following technical solutions:

[0005] The present invention provides a multi-channel transceiver microwave link structure, which includes 4 groups of independent frequency conversion channels and a signal distribution network. Each group of frequency conversion channels includes a digital signal processing board, an intermediate frequency filter, a mixer, a radio frequency filter, an amplifier, and an antenna array. The signal distribution network includes a microwave switch matrix, and the microwave switch matrix is a 2×4 microwave switch matrix. The 2×4 microwave switch matrix is divided into a first part and a second part with the output port of the power divider as the boundary. The first part consists of an independent first 1-to-4 power division module and a second 1-to-4 power division module. The circuit boards of the first 1-to-4 power division module and the second 1-to-4 power division module are both placed horizontally. The first 1-to-4 power division module includes 3 two-way power dividers and forms 4 outputs. The second 1-to-4 power division module includes 3 two-way power dividers and forms 4 outputs. The 4 outputs of the first 1-to-4 power division module are arranged in one-to-one correspondence with the 4 outputs of the second 1-to-4 power division module to form 4 groups of 2 outputs. The second part consists of 4 independent 2-to-1 switch modules. The 4 independent 2-to-1 switch modules are respectively connected to the output ports of the 4 groups of 2 outputs through radio frequency connectors. The circuit boards of the 4 independent 2-to-1 switch modules are all placed vertically. The structures of the first 1-to-4 power division module and the second 1-to-4 power division module are the same. The signal distribution network is used to provide 4 frequency conversion local oscillator signals LO1, LO2, LO3, and LO4 that can be of the same frequency or different frequencies.

[0006] Further, the signal distribution network further includes a first frequency hopping source and a second frequency hopping source, and the first frequency hopping source and the second frequency hopping source are independent of each other.

[0007] Further, the first 1-to-4 power divider module is correspondingly arranged with the first frequency hopping source, and the second 1-to-4 power divider module is correspondingly arranged with the second frequency hopping source.

[0008] Further, the first 1-to-4 power divider module, the second 1-to-4 power divider module, and the 4 independent 2-to-1 switch modules are all shielded by independent structural boxes.

[0009] Further, the circuits of the first 1-to-4 power divider module and the second 1-to-4 power divider module both adopt the cascading method of two-stage binary tree type 1-to-2 equal power divider circuits.

[0010] Further, the 4 2-to-1 switch modules all adopt symmetric circuit designs.

[0011] Further, the 2-to-1 switch module includes 2 single-pole single-throw switches and 1 single-pole double-throw switch. The 2 single-pole single-throw switches are connected in parallel and then connected in series with the single-pole double-throw switch. The 2 single-pole single-throw switches cooperate with a group of 2-way outputs.

[0012] Further, the operating frequencies of the two-way power divider, the single-pole single-throw switch, and the single-pole double-throw switch are all in the Ka band.

[0013] Further, each frequency conversion channel has two operating states: transmitting and receiving.

[0014] The present invention also provides a method for generating a time-domain cover signal. Using the above multi-channel transceiver microwave link structure, the method for generating a time-domain cover signal includes:

[0015] Set two independent frequency hopping sources to two different operating frequencies f1 and f2, where f1 is the actual operating frequency point of the radar to which the microwave link belongs, and f2 is the cover signal frequency point for electronic countermeasures;

[0016] During the transmitting state of the multi-channel transceiver microwave link, multiple transmitting signals are transmitted. When only 1 main signal is being transmitted, LO1, LO2, LO3, and LO4 simultaneously select the first frequency hopping source. During the remaining time intervals of the transmitting state, LO1, LO2, LO3, and LO4 simultaneously select the second frequency hopping source to release the cover signal;

[0017] During the receiving state of the multi-channel transceiver microwave link, LO1, LO2, LO3, and LO4 simultaneously select the first frequency hopping source to receive the main signal echo, and after down-conversion, the final intermediate frequency echo signal is generated; at this time, since the radio frequency of the cover signal echo does not match the receiving local oscillator frequency point, no effective intermediate frequency echo can be generated after down-conversion, and it will not affect the reception of the main signal.

[0018] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0019] a) The signal distribution network adopted by the multi-channel transceiver microwave link structure of the present invention uses a 2×4 dimensional microwave switch matrix. The 2×4 dimensional microwave switch matrix is divided into a first part and a second part with the output port of the power divider as the boundary. The first part consists of an independent first 1-to-4 power division module and a second 1-to-4 power division module. The circuit boards of the first 1-to-4 power division module and the second 1-to-4 power division module are both horizontally placed, constituting 4 groups of 2-way outputs; the second part consists of 4 independent 2-to-1 switch modules. The 4 independent 2-to-1 switch modules are respectively connected to the output ports of the 4 groups of 2-way outputs through RF connectors, and the circuit boards of the 4 independent 2-to-1 switch modules are all vertically placed. By means of module splitting and the above-mentioned 2D three-dimensional circuit structure layout, the generation of cross branches is avoided, and thus the technical problems caused by the existence of cross branches are overcome.

[0020] b) The multi-channel transceiver microwave link structure of the present invention includes two independent frequency hopping sources. Without increasing the number of frequency hopping sources, 4 frequency-converted local oscillator signals LO1, LO2, LO3, and LO4 that can be of the same frequency or different frequencies can be output through this microwave switch matrix.

[0021] c) The characteristic that the electrical lengths of all signal branches of the 2×4 switch matrix module of the multi-channel transceiver microwave link structure of the present invention are strictly equal can ensure the signal phase consistency when LO1, LO2, LO3, and LO4 select different frequency hopping sources.

[0022] d) The 2×4 microwave switch matrix of the multi-channel transceiver microwave link structure of the present invention can work up to the Ka band without increasing the number of frequency hopping sources. In the same-frequency mode, the output LO1, LO2, LO3, and LO4 meet the phase consistency requirements (the signals of each output port have good phase consistency at high and low temperatures), and in the different-frequency mode, the 60 dB channel isolation requirement is met; in addition, using a similar structure topology, theoretically, it has the ability to expand the function of any m×n dimensional switch matrix.

[0023] e) The signal distribution network adopted by the multi-channel transceiver microwave link structure of the present invention can output 4 frequency-converted local oscillator signals LO1, LO2, LO3, and LO4 that can be of the same frequency or different frequencies in the case of including two independent frequency hopping sources. Therefore, it can generate time-domain cover signals and can effectively cover the real signals of the radar during electronic countermeasures.

[0024] Other features and advantages of the present invention will be described in the subsequent specification, and part of them will become obvious from the specification or be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures specifically pointed out in the written specification and the drawings. Brief Description of the Drawings

[0025] The drawings are only for the purpose of showing specific embodiments and are not considered as a limitation to the present invention. Throughout the drawings, the same reference signs denote the same components.

[0026] Figure 1 It is a schematic diagram for generating a 2-channel frequency-converted local oscillator signal;

[0027] Figure 2 It is a block diagram (planar layout) of a 2×2 microwave switch matrix circuit;

[0028] Figure 3 It is a schematic diagram for generating a 4-channel frequency-converted local oscillator signal of the present invention;

[0029] Figure 4 It is a block diagram of a 2×4 microwave switch matrix circuit of the present invention;

[0030] Figure 5 It is a block diagram of a binary tree type 1-to-4 equal power splitter circuit of the present invention;

[0031] Figure 6 It is a schematic diagram of a multi-channel transceiver microwave link structure of the present invention.

[0032] Reference Signs:

[0033] 1 - First frequency hopping source, 2 - Second frequency hopping source. Detailed Description of the Preferred Embodiments

[0034] The following will specifically describe the preferred embodiments of the present invention in conjunction with the drawings, wherein the drawings form a part of the present invention and are used together with the embodiments of the present invention to explain the principle of the present invention. To enhance the understanding of the present invention, specific details are described in detail in the following preferred embodiments, and those skilled in the art can fully understand the present invention without these descriptions. Except for special instructions, the device models in the embodiments of the present invention are not subject to other restrictions, and any device that can perform the corresponding functions can be used. In addition, well-known elements, circuits, and methods are not described in detail to avoid unnecessary confusion to the essence of the present invention.

[0035] The solution adopted by the inventor for the current dual-channel transceiver microwave link is as follows: The dual-channel transceiver microwave link includes 2 sets of independent frequency conversion channels. The transceiver microwave link has two operating states: transmitting and receiving. In the transmitting state, 2 independent baseband modulation signals are provided by an external digital signal processing board, and are respectively up-converted through 2 frequency conversion local oscillator signals LO1 and LO2 to achieve spectral shift, generating 2 radio frequency transmission signals, which are fed into 2 different antenna arrays; In the receiving state, the radio frequency echo signals received by the 2 antenna arrays are respectively down-converted through the frequency conversion local oscillator signals LO1 and LO2 to generate 2 intermediate frequency echo signals, which are output to the digital signal processing board for analysis and processing. As Figure 2 shown, the dual-channel transceiver microwave link design uses 2 independent frequency hopping sources to generate the LO1 and LO2 local oscillator signals. According to the frequency and phase consistency of the transmission signals of the 2 antenna arrays, the operating mode of the transceiver microwave link can be divided into the same-frequency operating mode or the different-frequency operating mode. In the same-frequency mode, it is required that the LO1 and LO2 signals must come from the same frequency hopping source. At this time, LO1 and LO2 not only need to meet the frequency consistency, but also need to maintain the phase consistency. In the different-frequency mode, the LO1 and LO2 signals each correspond to 1 frequency hopping source. At this time, the output signal frequencies of the 2 frequency hopping sources are different values. To achieve the characteristic that the frequency hopping time index of the local oscillator signal is not greater than 200 ns, it is required that both the LO1 and LO2 signals can be freely and quickly switched between the 2 frequency hopping sources by means of an electronic switch.

[0036] Combined with the above requirements, generally a 2×2 microwave switch matrix is designed between the 2 frequency hopping sources and the LO1 and LO2 signal ports. The internal circuit is in a planar layout. The devices include 2 power dividers, 4 single-pole single-throw switches (SPST), and 2 single-pole double-throw switches (SPDT). The circuit structure block diagram is as Figure 1 shown. At any time, the LO1 or LO2 signal can select the first frequency hopping source or the second frequency hopping source, and the frequency hopping source selection of LO1 and LO2 is independent of each other and does not affect each other. In the different-frequency mode, LO1 and LO2 need to meet the channel isolation index of 60 dB. The switch isolation of the SPDT in the circuit is generally 35-50 dB, which does not meet the isolation requirement of 60 dB. Therefore, 1 SPST is connected in series on each branch before the SPDT. The isolation is generally 35-50 dB. After the two-stage switches are cascaded, a switch isolation index better than 60 dB is achieved. In the same-frequency mode, LO1 and LO2 may select the first frequency hopping source at the same time, or may select the second frequency hopping source at the same time. At this time, it is required that LO1 and LO2 have phase consistency. Since the power dividers, SPSTs, and SPDT devices of the same model and specification have good phase consistency, in the circuit design, it is mainly necessary to control the phase consistency of the transmission line, that is, the electrical length of the transmission line. For Figure 2The circuit needs to meet the following requirements: the signal branches of a1 and b1 have equal electrical lengths; the signal branches of a2 and b2 have equal electrical lengths; the signal branches of c1 and d1 have equal electrical lengths; the signal branches of c2 and d2 have equal electrical lengths. The above requirements for equal electrical lengths are mainly controlled by controlling the length of the printed circuit board transmission line and designing the same via structure for different signal branches.

[0037] Currently, in the design of a new multi-channel radar system studied by the inventor, the required independent frequency conversion chain is expanded from 2 channels to 4 channels. Therefore, it is necessary to provide 4 frequency conversion local oscillator signals LO1, LO2, LO3, and LO4 that can be of the same frequency or different frequencies; at the same time, the operating frequency of the new radar is expanded, and it is required that the operating frequencies of the LO1, LO2, LO3, and LO4 signals reach the Ka band at the highest. Without increasing the number of frequency hopping sources, it is necessary to design a 2×4 microwave switch matrix that can work up to the Ka band, and it is required that the outputs LO1, LO2, LO3, and LO4 meet the phase consistency requirements in the same frequency mode and the 60 dB channel isolation requirement in the different frequency mode.

[0038] Under the above requirements, if a 2×4 microwave switch matrix is designed based on the existing 2×2 microwave switch matrix, the following technical problems will exist: in the existing 2×2 microwave switch matrix, there is a pair of cross branches such as the a2 and b2 branches. It is necessary to make a2 and b2 transmit on different layers by means of signal via punching through multiple layers of the printed circuit board to achieve the interleaved interconnection of signal ports. If the above planar layout method is adopted, there will be a large number of cross branches in the 2×4 microwave switch matrix. In order to ensure the microwave signal isolation, each branch in the cross branch must independently occupy 1 layer, and there must be a complete ground layer for isolation between other branches, which will ultimately lead to too many printed circuit board layers and is not feasible in actual engineering.

[0039] In the case of not increasing the number of frequency hopping sources, the present invention needs to design a 2×4 microwave switch matrix that can work up to the Ka band, and it is required that the outputs LO1, LO2, LO3, and LO4 meet the phase consistency requirements in the same frequency mode and the 60 dB channel isolation requirement in the different frequency mode.

[0040] Embodiment 1

[0041] As Figures 3-6As shown in the figure, this embodiment provides a multi-channel transceiver microwave link structure. The multi-channel transceiver microwave link structure includes a signal distribution network. Among them, the signal distribution network includes a first frequency hopping source 1 (SRC1), a second frequency hopping source 2 (SRC2), and a microwave switch matrix. The microwave switch matrix is a 2×4 microwave switch matrix. The 2×4 microwave switch matrix is divided into a first part and a second part with the output port of the power divider as the boundary. The first part consists of an independent first 1-to-4 power dividing module and a second 1-to-4 power dividing module. The first 1-to-4 power dividing module is correspondingly arranged with the first frequency hopping source 1 (SRC1), and the second 1-to-4 power dividing module is correspondingly arranged with the second frequency hopping source 2 (SRC2). The first frequency hopping source 1 and the second frequency hopping source 2 are independent of each other; the circuit boards of the first 1-to-4 power dividing module and the second 1-to-4 power dividing module are both horizontally placed; the first 1-to-4 power dividing module includes 3 two-way power dividers and forms 4 outputs; the second 1-to-4 power dividing module includes 3 two-way power dividers and forms 4 outputs; the 4 outputs of the first 1-to-4 power dividing module are correspondingly arranged with the 4 outputs of the second 1-to-4 power dividing module 2 one by one, constituting 4 groups of 2 outputs; the second part consists of 4 independent 2-to-1 switch modules. The 4 independent 2-to-1 switch modules are respectively connected to the output ports of the 4 groups of 2 outputs through RF connectors. The circuit boards of the 4 independent 2-to-1 switch modules are all vertically placed; the first frequency hopping source 1 and the second frequency hopping source 2 cooperate with the 2×4 microwave switch matrix to provide 4 groups of frequency-converted local oscillator signals LO1, LO2, LO3, and LO4 that can be of the same frequency or different frequencies.

[0042] That is, with the output port of the power divider as the boundary, the entire 2×4 microwave switch matrix is divided into 2 parts. The first part is 2 independent 1-to-4 power dividing modules, that is, the first 1-to-4 power dividing module and the second 1-to-4 power dividing module; the second part is 4 independent 2-to-1 switch modules. In terms of structural topology design, the circuit boards of the 1-to-4 power dividing module and the 2-to-1 switch module are perpendicular to each other, and 8 pairs of internal interfaces generated by the structure division are buckled one by one through RF connectors. It can be seen that this embodiment avoids the generation of cross branches through the way of module splitting and the above-mentioned 2D three-dimensional circuit structure layout, and thus overcomes the technical problems caused by the existence of cross branches.

[0043] Specifically, the structures of the first 1-to-4 power dividing module and the second 1-to-4 power dividing module are the same.

[0044] Specifically, the structures of the 4 independent 2-to-1 switch modules are the same.

[0045] Specifically, the above-mentioned first 1-to-4 power dividing module can output four intermediate port signals a1, a2, a3, and a4; the above-mentioned second 1-to-4 power dividing module can output four intermediate port signals b1, b2, b3, and b4.

[0046] Through the above configuration method, the microwave switch matrix of the signal distribution network avoids the generation of cross branches. Without increasing the number of frequency hopping sources (two independent frequency hopping sources), the microwave switch matrix can output four variable-frequency local oscillator signals LO1, LO2, LO3, and LO4 that can be of the same frequency or different frequencies.

[0047] Specifically, in order to increase the operating frequency, the first 1-to-4 power divider module, the second 1-to-4 power divider module, and four independent 2-to-1 switch modules are all shielded by independent structural enclosures.

[0048] Through the above configuration method, after the module is split, the two 1-to-4 power divider modules at the input stage and the four 2-to-1 switch modules at the output stage are all shielded by independent structural enclosures. The internal layout of each sub-module is planar, and there is no signal through-layer situation. Therefore, there is no problem of deterioration of isolation caused by signal through-layer cross transmission, avoiding the problem of deterioration of cross-branch isolation caused by the increase of operating frequency in the traditional 2×2 microwave switch matrix in engineering.

[0049] In the above embodiment, in order to achieve the phase consistency index, as Figures 4-5 shown, the circuits of the first 1-to-4 power divider module and the second 1-to-4 power divider module both adopt the cascading method of two-stage binary tree type 1-to-2 equal power divider circuits.

[0050] In this embodiment, the phase consistency index is achieved through the equal electrical length design of the planar circuit. The circuits of the two 1-to-4 power divider modules at the input stage adopt the cascading method of two-stage binary tree type 1-to-2 equal power divider circuits as Figure 5 shown, ensuring that the phase shift characteristics of the four intermediate port signals a1, a2, a3, and a4 relative to the IN1 input signal are completely the same, and the phase shift characteristics of the four intermediate port signals b1, b2, b3, and b4 relative to the IN2 input signal are completely the same.

[0051] In the above embodiment, in order to achieve the phase consistency index, as Figure 5 shown, the four 2-to-1 switch modules all adopt a symmetric circuit design. Any 2-to-1 switch module includes two single-pole single-throw switches (SPST) and one single-pole double-throw switch (SPDT). The two single-pole single-throw switches (SPST) are connected in parallel and then connected in series with the single-pole double-throw switch (SPDT). The two single-pole single-throw switches (SPST) cooperate with a group of two-way outputs.

[0052] In the above embodiment, one 2-to-1 switch module corresponds to a group of two-way outputs. The corresponding two-way outputs (as Figure 6 shown, there are a total of four groups of two-way outputs, namely a1, b1; a2, b2; a3, b3; a4, b4) are respectively set in one-to-one correspondence with two SPSTs.

[0053] In this embodiment, the four 1-of-2 switch modules at the output stage adopt a symmetric circuit design to ensure that the cn (n = 1, 2, 3, 4) branches and the dn branches are strictly symmetric and have the same electrical length.

[0054] In addition, to further ensure the phase consistency of the entire switch matrix OUT1(LO1), OUT2(LO2), OUT3(LO3), and OUT4(LO4) in the homologous mode, preferably, in the design of the structural box body, the installation dimensional tolerance of the RF connector is strictly controlled to ensure the phase consistency of the signal transmission of the RF connector.

[0055] It can be seen that the above scheme of this embodiment overcomes the problems in the existing planar layout structure, such as the sudden change of the transmission line impedance and phase shift characteristics caused by the signal perforation of the printed circuit board, the different inner layers for the cross branches to transmit, and the difference in their phase shift characteristics, which is more difficult to control at higher frequencies. Eventually, it leads to the temperature drift of the phase difference of the LO1, LO2, LO3, and LO4 signals in the high and low temperature environments, affecting the amplitude-phase consistency and stability between different transceiver channels of the radar.

[0056] In the above embodiment, to increase the operating frequency of the full link of the switch matrix module, the operating frequencies of the power divider, SPST, and SPDT devices are in the Ka band.

[0057] Specifically, the RF connector is an SSMP type micro RF connector.

[0058] Specifically, the operating frequency of the SSMP type micro RF connector is 50 GHz.

[0059] It can be seen that in the embodiment of the present invention, the isolation of the SPST and SPDT switches in the Ka band is generally 35 - 45 dB. After the two-stage switches are cascaded, the theoretical channel isolation is better than 70 dB, still meeting the isolation index requirement of 60 dB.

[0060] Specifically, in this embodiment, the typical sizes of the first 1-to-4 power division module and the second 1-to-4 power division module are both 20 mm × 40 mm × 10 mm, the typical size of each 1-of-2 switch module is 20 mm × 10 mm × 20 mm, and the size of the assembled 2×4 switch matrix module is 40 mm × 40 mm × 20 mm.

[0061] Specifically, the switching rate of the 2×4 microwave switch matrix is less than 50 ns.

[0062] Specifically, the multi-channel transceiver microwave link structure also includes 4 groups of independent frequency conversion channels.

[0063] Specifically, each group of frequency conversion channels in this embodiment includes a digital signal processing board, an intermediate frequency filter, a mixer, a radio frequency filter, an amplifier, and an antenna array.

[0064] Specifically, the digital signal processing board is used to provide baseband modulation signals.

[0065] Specifically, the intermediate frequency filter, mixer, radio frequency filter and amplifier are used to achieve frequency conversion.

[0066] Specifically, each group of frequency conversion channels in this embodiment has two working states: transmitting and receiving.

[0067] Specifically, in the transmitting state, the digital signal processing board provides 4 independent baseband modulation signals, which are respectively input into 4 intermediate frequency filters, and are respectively mixed with 4 frequency conversion local oscillator signals LO1, LO2, LO3, LO4 (implemented by 2 independent frequency hopping sources and the above-mentioned microwave switch matrix), and then pass through the mixer, radio frequency filter and amplifier for up-conversion to achieve spectrum shift, generate 4 radio frequency transmission signals, and feed them into different 4 groups of antenna arrays.

[0068] Specifically, in the receiving state, the 4 groups of antenna arrays receive radio frequency echo signals, which respectively pass through the amplifier, radio frequency filter, and are mixed with the frequency conversion local oscillator signals LO1, LO2, LO3, LO4 (implemented by 2 independent frequency hopping sources and the above-mentioned microwave switch matrix) through the mixer for down-conversion to generate 4 intermediate frequency echo signals, and output them to the digital signal processing board for analysis and processing.

[0069] Embodiment 2

[0070] This embodiment also provides a method for generating time-domain cover signals using the multi-channel transceiver microwave link structure of the above-mentioned Embodiment 1:

[0071] Set 2 independent frequency hopping sources to 2 different operating frequencies f1 and f2, where f1 is the actual operating frequency point of the radar to which the microwave link belongs, and f2 is the cover signal frequency point for electronic countermeasures;

[0072] During the transmitting state of the multi-channel transceiver microwave link, multiple transmission signals are transmitted. During the transmission of only 1 main signal, LO1, LO2, LO3, and LO4 are simultaneously gated to the first frequency hopping source 1, and in the remaining transmission state time intervals, LO1, LO2, LO3, and LO4 are simultaneously gated to the second frequency hopping source 2 for releasing cover signals;

[0073] During the receiving state of the multi-channel transceiver microwave link, LO1, LO2, LO3, and LO4 are simultaneously gated to the first frequency hopping source 1 for receiving the main signal echo, and the final intermediate frequency echo signal is generated after down-conversion; while at this time, the echo of the cover signal cannot generate an effective intermediate frequency echo after down-conversion because its radio frequency is not matched with the receiving local oscillator frequency point, and thus will not affect the reception of the main signal.

[0074] For a multi-channel microwave link, the signal phase consistency when LO1, LO2, LO3, and LO4 select different frequency hopping sources has a great impact on the amplitude-phase characteristics of the entire system. Therefore, the characteristic that the electrical lengths of all signal branches of the 2×4 switch matrix module of the present invention are strictly equal has important engineering application value.

[0075] As described above, only the preferred specific embodiments of the present invention are provided, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A multi-channel transceiver microwave link structure, characterized in that, The multi-channel transceiver microwave link structure includes 4 groups of independent frequency conversion channels and a signal distribution network. Each group of the frequency conversion channels includes a digital signal processing board, an intermediate frequency filter, a mixer, a radio frequency filter, an amplifier, and an antenna array. The signal distribution network includes a microwave switch matrix, which is a 2×4 microwave switch matrix. The 2×4 microwave switch matrix is divided into a first part and a second part with the output port of the power divider as the boundary. The first part consists of an independent first 1-to-4 power division module and a second 1-to-4 power division module. The circuit boards of the first 1-to-4 power division module and the second 1-to-4 power division module are both placed horizontally. The first 1-to-4 power division module includes 3 two-way power dividers and forms 4 outputs. The second 1-to-4 power division module includes 3 two-way power dividers and forms 4 outputs. The 4 outputs of the first 1-to-4 power division module are set in one-to-one correspondence with the 4 outputs of the second 1-to-4 power division module, constituting 4 groups of 2 outputs. The second part consists of 4 independent 2-to-1 switch modules. The 4 independent 2-to-1 switch modules are respectively connected to the output ports of the 4 groups of 2 outputs through radio frequency connectors. The circuit boards of the 4 independent 2-to-1 switch modules are all placed vertically. The structures of the first 1-to-4 power division module and the second 1-to-4 power division module are the same. The signal distribution network is used to provide 4 frequency conversion local oscillator signals LO1, LO2, LO3, and LO4 that can be of the same frequency or different frequencies.

2. The multi-channel transceiver microwave link structure according to claim 1, wherein The signal distribution network further includes a first frequency hopping source (1) and a second frequency hopping source (2), and the first frequency hopping source (1) and the second frequency hopping source (2) are independent of each other.

3. The multi-channel transceiver microwave link structure according to claim 2, characterized in that, The first 1-to-4 power division module is correspondingly set with the first frequency hopping source (1), and the second 1-to-4 power division module is correspondingly set with the second frequency hopping source (2).

4. The multi-channel transceiver microwave link structure according to claim 1, characterized in that The first 1-to-4 power division module, the second 1-to-4 power division module, and the 4 independent 2-to-1 switch modules are all shielded by independent structural boxes.

5. The multi-channel transceiver microwave link structure according to claim 1, characterized in that The circuits of the first 1-to-4 power division module and the second 1-to-4 power division module both adopt the cascading method of two-stage binary tree type 1-to-2 equal power division circuits.

6. The multi-channel transceiver microwave link structure according to claim 1, characterized in that All 4 2-to-1 switch modules adopt symmetric circuit designs.

7. The multi-channel transceiver microwave link structure according to claim 6, characterized in that The 2-to-1 switch module includes 2 single-pole single-throw switches and 1 single-pole double-throw switch. The 2 single-pole single-throw switches are connected in parallel and then connected in series with the single-pole double-throw switch. The 2 single-pole single-throw switches cooperate with a group of 2 outputs.

8. The multi-channel transceiver microwave link structure according to claim 7, wherein The operating frequencies of the two-way power divider, the single-pole single-throw switch, and the single-pole double-throw switch are all in the Ka band.

9. The multi-channel transceiver microwave link structure according to claim 1, characterized in that, Each of the frequency conversion channels has two operating states: transmitting and receiving.

10. A method for generating a time-domain cover signal, characterized in that, Adopting the multi-channel transceiver microwave link structure according to any one of claims 1-9, the time domain cover signal generation method includes: Setting 2 independent frequency hopping sources to 2 different operating frequencies f1 and f2, where f1 is the true operating frequency point of the radar to which the microwave link belongs, and f2 is the cover signal frequency point for electronic countermeasures. During the transmission state of the multi-channel transceiver microwave link, multiple transmission signals are transmitted. When only 1 main signal is transmitted, LO1, LO2, LO3, and LO4 simultaneously select the first frequency hopping source (1). During the remaining transmission state time intervals, LO1, LO2, LO3, and LO4 simultaneously select the second frequency hopping source (2) for releasing cover signals. During the reception state of the multi-channel transceiver microwave link, LO1, LO2, LO3, and LO4 simultaneously select the first frequency hopping source (1) to receive the main signal echo, and the final intermediate frequency echo signal is generated after down-conversion. At this time, since the echo of the cover signal does not match the receiving local oscillator frequency point in terms of its radio frequency, no effective intermediate frequency echo can be generated after down-conversion, and it will not affect the reception of the main signal.

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