Multi-band shared phased array transceiver system based on optical pulse and implementation method thereof

Abstract

A kind of multi-band shared phased array transceiver system based on optical pulse and its implementation method, based on microwave photonics technology, uses optical pulse for signal generation and up-conversion and down-conversion, and the phase control of multi-band is realized by changing the delay of optical pulse in up-conversion and down-conversion process, and then the multi-band signal generation and beam forming transceiving are completed simultaneously by using a set of equipment.The compactness of multi-band phased array radar system and the coherence between multiple bands are improved, the power consumption, volume and cost of the system are greatly reduced, and the complexity of multi-band signal fusion algorithm can be simplified.

Description

TECHNICAL FIELD

[0001] The present application relates to microwave photonics technology, in particular to a multi-band shared phased array transceiver technology based on optical pulses and an implementation method thereof. BACKGROUND

[0002] With the continuous progress of radar technology, multi-band radar has become an important research direction in the field of radar. Multi-band radar can capture the unique electromagnetic scattering characteristics of targets at different frequency bands, providing more abundant and comprehensive information for target recognition, and significantly improving the recognition accuracy and efficiency. In addition, by fusing multi-band received signals, multi-band radar can effectively enhance the detection resolution, especially the detection ability of stealth targets in complex environments, because existing stealth technology is often effective only in limited frequency bands. At the same time, compared with single-band radar, multi-band radar shows stronger anti-interference ability, ensuring stable and reliable detection in complex electromagnetic environments.

[0003] However, traditional electronic radar transmitters face many challenges in implementing multi-band operation. Each band usually needs an independent set of hardware support, which not only greatly increases the complexity and power consumption of the system, but also introduces signal inconsistency problems caused by factors such as vibration time delay and phase difference between multiple sets of hardware, which need complex compensation algorithms for processing. In addition, limited by the inherent bandwidth of electronic systems, traditional radars are difficult to generate and efficiently process high-frequency, large-bandwidth multi-band radar signals, limiting further performance improvement.

[0004] To overcome the above problems, microwave photonics technology provides a new way for constructing an efficient and compact multi-band radar system due to its large instantaneous bandwidth, strong parallel signal processing capability, anti-electromagnetic interference, and multi-dimensional multiplexing. Among them, using ultra-short optical pulse trains to realize multi-band up-conversion and down-conversion of intermediate frequency signals has become one of the key technologies. [P. Ghelfi, et al., "Photonics for Radars Operating on Multiple Coherent Bands," in Journal of Lightwave Technology, vol. 34, no. 2, pp. 500-507, 2016.] In addition, through polarization multiplexing technology to generate dual-band signals and combining with photonics mixing technology to remove signal chirp, the boundary of multi-band radar signal processing is further widened. [X. Wang, et al., "Dual-Band Coherent Microwave Photonic Radar Using Linear Frequency Modulated Signals With Arbitrary Chirp Rates," in IEEE Journal of Selected Topics in Quantum Electronics, vol. 29, no. 6, pp. 1-9, 2023.] However, the existing researches are mostly focused on traditional mechanical scanning radars, which are difficult to be directly applied to phased array radar systems, and lack of effective phase control mechanism for phased array multi-band beamforming. Since its inception, phased array radar technology has become an important part of radar and communication systems due to its high flexibility of electronically controlling beam direction, strong anti-interference, high signal-to-noise ratio, and fast scanning response, and is widely used in military reconnaissance, space exploration, and radio astronomy. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provides a multi-band shared phased array transceiver system based on optical pulses and an implementation method thereof. By using optical pulses as signal carriers and controlling the delay of optical pulses during up-conversion and down-conversion, the phase control of multi-band signals is realized, thereby completing the generation, beamforming, and transceiving of multi-band signals in one set of equipment. This not only greatly improves the compactness and coherence between bands of the multi-band phased array radar system, but also significantly reduces the power consumption, volume, and cost of the system, opening up a new direction for the development of radar technology.

[0006] The technical solution of the present application is as follows:

[0007] In one aspect, the present application provides a multi-band shared phased array transceiver system based on optical pulses, characterized in that it comprises:

[0008] At the signal transmitting end: the first optical pulse generator generates first optical pulses, which are divided into two paths after being adjusted by the first delay line. In one path, the baseband signal output by the digital-to-analog converter is modulated onto the first optical pulses by the first modulator and then phase-shifted by the first phase shifter, to realize up-conversion of the baseband to multiple frequency bands, and then input to the balanced photodetector. In the other path, the first optical pulses are input to the balanced photodetector after being adjusted by the attenuator. The signals detected by the balanced photodetector are amplified by the first amplifier and then transmitted by the antenna array.

[0009] At the signal receiving end: the second optical pulse generator generates second optical pulses, which are adjusted by the second delay line. The multi-band signals received by the antenna are modulated onto the second optical pulses by the second modulator, to realize down-conversion to the baseband. The optical signals are converted into electrical signals by the photodetector, filtered by the low-pass filter, phase-shifted by the second phase shifter, and then quantized into digital signals by the analog-to-digital converter.

[0010] Preferably, the center frequency f and the bandwidth B of the baseband signal generated by the digital-to-analog converter satisfy the following conditions:

[0011]

[0012] wherein f s1 is the repetition frequency of the first optical pulses generated by the first optical pulse generator, and f s2 is the repetition frequency of the second optical pulses generated by the second optical pulse generator, and

[0013] Further, the signal transmitting end further comprises a first phase shifter for adjusting the phase of the signal to realize beamforming of the multi-band signal.

[0014] Preferably, the first phase shifter and the second phase shifter are both digital phase shifters.

[0015] Further, it further comprises a power divider and a combiner. The power divider is used to distribute the output signal of the digital-to-analog converter to the first phase shifters of multiple array elements, and the combiner is used to combine the received signals of multiple array elements and then input to the analog-to-digital converter.

[0016] Preferably, the first optical pulse generator and the second optical pulse generator are both actively mode-locked lasers, passively mode-locked lasers, or optical frequency combs generated based on external modulation method.

[0017] Preferably, the first modulator and the second modulator are both Mach-Zehnder intensity modulators, lithium niobate electro-optic modulators, polymer electro-optic modulators, silicon-based integrated electro-optic modulators, acousto-optic modulators, or spatial light modulators.

[0018] Preferably, the first delay line and the second delay line are electrically driven delay lines, micro-ring delay lines or delay lines based on high-order dispersion optical fiber.

[0019] In another aspect, the application also provides a multi-band implementation method using the above-mentioned optical pulse-based multi-band shared phased array transceiver system, characterized in that it comprises the following steps:

[0020] ① The first optical pulse generator generates a first optical pulse at the signal transmitting end, and the second optical pulse generator generates a second optical pulse at the signal receiving end;

[0021] ② At the signal transmitting end, the baseband signal output by the digital-to-analog converter is phase-shifted by the first phase shifter and then modulated onto the optical pulse by the first modulator to realize up-conversion to multiple frequency bands; at the same time, the other optical pulse is adjusted in power by the attenuator and then differentially detected with the output of the first modulator, and after amplification, it is transmitted by the antenna array;

[0022] ③ At the signal receiving end, the multi-band signal received by the antenna is amplified and then modulated onto the second optical pulse by the second modulator to realize down-conversion to the baseband; the optical signal is converted into an electrical signal by the photodetector, filtered by the low-pass filter and phase-shifted by the second phase shifter, and then quantized into a digital signal by the analog-to-digital converter;

[0023] ④ By adjusting the first delay line, the second delay line, the first phase shifter and the second phase shifter, the phase control of the multi-band signal in the transmitting and receiving processes is realized to ensure the coherence of the multi-band signal and the accuracy of the beam forming.

[0024] Further, the center frequency f and the bandwidth B of the baseband signal generated by the digital-to-analog converter satisfy the following conditions:

[0025]

[0026] Wherein, f s1 is the repetition frequency of the first optical pulse generated by the first optical pulse generator, f s2 is the repetition frequency of the second optical pulse generated by the second optical pulse generator, and

[0027] Further, the delay Δt1 of the first delay line and the phase shift of the first phase shifter in the step ④ are adjusted to satisfy the following conditions:

[0028]

[0029]

[0030] Alternatively, the delay Δt2 of the second delay line and the phase shift of the second phase shifter are adjusted to satisfy the following conditions: ​

[0031]

[0032] Both can realize multi-band phase shift and multi-band beamforming, and complete multi-band signal generation and transmission; among them, is the flight time difference between the transmitting array elements, is the transit time difference between the receiving array elements, and is the pulse period of the optical pulse at the transmitting end and the optical pulse at the receiving end.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] 1) The present invention realizes the shared transmission and reception of multiple frequency band signals through optical pulse technology, thereby improving the utilization rate of spectrum resources. It is particularly suitable for application scenarios that require the simultaneous processing of multiple frequency band signals, such as integrated radar communication systems. By using optical pulses as carriers and combining them with high-speed optoelectronic conversion technology, efficient processing of broadband signals is achieved, supporting signal bandwidths of up to tens of GHz, and improving data transmission rates and system response speeds. Optical pulses are used to realize the generation, frequency conversion, and phase shifting of multi-band signals in a single link, ensuring phase coherence between multiple bands. This eliminates the need for complex algorithms for phase compensation in the multi-band fusion process, thereby reducing the complexity of the algorithm in the processing.

[0035] 2) A balanced photodetector is used for differential detection, effectively eliminating the common-mode noise and frequency components of the optical pulse, improving the signal purity and signal-to-noise ratio. At the same time, a digital phase shifter is used for precise phase adjustment to ensure the accuracy of beamforming.

[0036] 3) The multi-band shared phased array transceiver technology and its implementation method proposed in this invention can simultaneously transmit and receive radar signals in multiple bands, acquiring more information about targets, significantly improving detection resolution, and enhancing anti-interference capabilities. Multiple bands share the same transceiver system, significantly reducing system redundancy and cost, improving system compactness, and reducing the weight and volume of the multi-band phased array system. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is an overall architecture diagram of an embodiment of a multi-band shared phased array transceiver system based on optical pulses of the present invention;

[0038] Figure 2 Schematic diagram of the first optical pulse simultaneously generating multi-band emission signals.

[0039] Figure 3 Schematic diagram of using balanced photodetector differential balanced detection to remove the first optical pulse frequency component and enhance the multi-band signal energy.

[0040] Figure 4 Schematic diagram for simultaneously down-converting the multi-band signal to baseband for the second light pulse. DETAILED DESCRIPTION

[0041] One specific embodiment of the present application is given below in combination with the drawings. The embodiment is implemented on the premise of the technical solution of the present application, and detailed implementation manners and processes are given, but the protection scope of the present application is not limited to the following embodiment.

[0042] Please refer to Figure 1 , Figure 1 The overall architecture diagram of the embodiment of the light-pulse-based multi-band shared phased array transceiving system of the present application is shown in the figure. As can be seen from the figure, the light-pulse-based multi-band shared phased array transceiving system comprises a first light pulse generator, a second light pulse generator, a first modulator, a second modulator, a first coupler, a second coupler, a first delay line, a second delay line, an attenuator, a balanced photodetector, a photodetector, a low-pass filter, a first phase shifter, a second phase shifter, a combiner, a power divider, an analog-to-digital converter, a digital-to-analog converter, a first amplifier, and a second amplifier.

[0043] At the signal generation and emission end: the first light pulse generator is a mode-locked laser, the output end of which is connected to the first coupler to provide a first light pulse for a plurality of phased array elements; the output end of the first coupler is connected to the input end of the first delay line; the first delay line is an electric delay line, the output end of which is divided into upper and lower two paths through a coupler, the upper path is connected to the light input end of the first modulator 1, and the lower path is connected to the input end of the attenuator.

[0044] The output end of the digital-to-analog converter is connected to the input end of the power divider, the output end of the power divider is connected to the input end of the first phase shifter of the plurality of array elements; the output end is connected to the radio frequency input end of the first modulator. The light output end of the first modulator is connected to the output end of the attenuator to the same direction input end and reverse input end of the balanced photodetector respectively; the output is connected to the input end of the first amplifier, and the output end of the first amplifier is connected to the antenna element of the transmitting array antenna. In the embodiment, the first phase shifter is a digital phase shifter, the first modulator is a Mach-Zehnder intensity modulator, the balanced photodetector is a large-bandwidth balanced photodetector, and the first amplifier is a power amplifier.

[0045] In the embodiment, the first light pulse generator generates a first light pulse with a repetition frequency of f s1 and a period of T s1The first optical pulse is transmitted by a first delay line, which adjusts the delay of the first optical pulse. The signal is then split into two paths by a coupler. The baseband signal output by the digital-to-analog converter is phase-shifted by a first phase shifter. The first modulator in the upper path modulates the phase-shifted signal onto the first optical pulse, which then up-converts the baseband signal to multiple frequency bands. An attenuator adjusts the power of the first optical pulse in the lower path. A balanced photodetector performs photoelectric conversion and differential detection between the upper and lower paths. The signal output by the balanced photodetector is amplified by an amplifier and radiated by the antenna array.

[0046] At the receiving end, the second optical pulse generator is an actively mode-locked laser, whose output is connected to a coupler to provide second optical pulses for multiple phased array elements. The output of the coupler is connected to the input of a second delay line. The second delay line is an electric delay line, whose output is connected to the optical input of a second modulator. The RF input of the second modulator is connected to the output of a second amplifier. The input of the second amplifier is connected to an antenna element of a receiving antenna array. The optical output of the second modulator is connected to the input of a photodetector. The output of the photodetector is connected to the input of a low-pass filter. The output of the low-pass filter is connected to the input of a second phase shifter. The output of the second phase shifter is connected to the input of a combiner. The combiner combines the outputs of the second phase shifters of multiple array elements into one path, and the output of the combiner is connected to the input of an analog-to-digital converter. In this embodiment, the second modulator is a Mach-Zehnder intensity modulator, the second amplifier is a power amplifier, and the second phase shifter is a digital phase shifter.

[0047] In this embodiment, the second optical pulse generator generates a repetition frequency of f s2 , with a period of T s2 The second optical pulse is transmitted by the antenna. The second delay line adjusts the delay of the second optical pulse. The second amplifier amplifies the multi-band signal received by the antenna. The second modulator modulates the amplified multi-band signal onto the second optical pulse, which down-converts the received multi-band signal to baseband. The photodetector converts the optical signal into an electrical signal, which is then filtered by a low-pass filter and phase-shifted by a phase shifter before being quantized into a digital signal by an analog-to-digital converter.

[0048] The working principle of the multi-band shared phased array transceiver system of the present invention is as follows:

[0049] The first optical pulse generator generates the first optical pulse 1u1(t), which is transmitted to the first modulator after being delayed by the first delay line. The digital-to-analog converter generates a center frequency of The baseband signal s0(t) with bandwidth B and duration T0 is phase shifted by the first phase shifter. After that, the first modulator modulates the signal onto the first added optical pulse and up-converts the baseband signal to multiple frequency bands. The above process can be expressed as:

[0050]

[0051] where p1(t,Δt1) is the output of the first modulator, Δt1 is the time delay of the first optical pulse adjusted by the first delay line, T M is the transfer function of the first modulator, and α is related to the modulation depth.

[0052] The uplink optical output is converted into an electrical signal by a balanced photoelectric detector, and the output electrical signal is affected by the bandwidth of the balanced photoelectric detector. The process is shown in FIG. 2. Figure 2

[0053] The downlink first optical pulse is adjusted to half of the power by an adjustable attenuator, and after photoelectric conversion, the electrical signal of the uplink is subtracted to eliminate the frequency components and common-mode noise of the first optical pulse, thereby generating a pure multi-band signal. Ignoring the amplitude coefficient of the signal, the process is represented as:

[0054]

[0055] k0 are coefficients determined by the bandwidth of the transmission channel, which represent the number of frequency bands of the output signal. The above process is shown in FIG. 3. Figure 3

[0056] When the transmitting end performs beamforming on the multi-band signal, let the beam angle be θ1, then the time difference t d1 between the array elements is ndsinθ1 / c; the frequency of the multi-band signal is Therefore, the required phase shift of the multi-band signal is That is,

[0057]

[0058] Since the phase change has periodicity when the phase is moved, it is not necessary to move the absolute value of the phase, but only to adjust the phase so that 2πf s1 Δt1=2πf s1 t d1 -2π[f s1 t d1 ], That is, adjusting the first delay line and the first phase shifter so that can achieve correct phase movement of the multi-band, realize multi-band beamforming, complete multi-band signal generation and transmission.

[0059] The process of the signal receiving end can be represented by the following formula:

[0060] The second optical pulse generator generates a second optical pulse. In order to ensure that aliasing does not occur in the signal transmission and reception process, the bandwidth B of the baseband signal, the repetition frequency f s1 of the first optical pulse generator, and the repetition frequency f​​s2 The relationship between the two needs to be satisfied The number of frequency bands received is That is, the multi-band signal supported by the transceiver system Wherein

[0061]

[0062] The multi-band signal received by the antenna is amplified by the amplifier, and the second modulator modulates the signal onto the uplink second optical pulse. The second optical pulse down-converts the multi-band signal to the baseband. The second delay line adjusts the delay of the second optical pulse to Δt2. The process can be represented as:

[0063]

[0064] After photoelectric conversion, only the signals within the bandwidth range are retained after phase shifting by the phase shifter, and the final signal input to the analog-to-digital converter is represented as:

[0065]

[0066] The above process is shown in Figure 4 .

[0067] When the receiving end performs beamforming reception on the multi-band signal, let the beam angle be θ2, then the time difference between the array elements is t d2 = ndsinθ2 / c, and the required phase shift of the multi-band signal is Then

[0068]

[0069] Similarly, when performing phase movement, it is not necessary to move the absolute amount of phase value, but only to move within the interval [-π, π]. The above phase shifting effect is true for wideband and narrowband signals. Therefore, only by adjusting the second delay line and the second phase shifter to make Multi-band beamforming can be achieved, and signal reception is completed.

[0070] The implementation method of the above multi-band shared phased array transceiver system based on optical pulses includes the following steps:

[0071] 1) The first optical pulse generator generates a first optical pulse with a repetition frequency of f s1 In this embodiment, f s1 takes a value of 11GHz. The second optical pulse generator generates a second optical pulse with a repetition frequency of f s2 In this embodiment, f s2 takes a value of 5GHz.

[0072] 2) The digital-to-analog converter generates a center frequency Bandwidth a linear frequency modulation signal, in the embodiment B=0.5GHz. After the first phase shifter, modulated to the first optical pulse by the first modulator.

[0073] 3) Adjust the attenuator, so that the optical power of the attenuator output is half of the first modulator output optical power.

[0074] 4) In the embodiment, the bandwidth of the balanced photodetector is 20GHz. The output of the first modulator and the output of the attenuator are photoelectrically converted by the balanced photodetector, and the differential balanced detection is simultaneously outputted 2.5-3GHz, 8-8.5GHz, 13.5-14GHz, 19-19.5GHz multi-band broadband signal.

[0075] 5) Adjust the first delay line and the first phase shifter so that Multi-band beamforming is achieved, and signal generation and transmission are completed.

[0076] 6) The broadband multi-band echo signal antenna receives 2.5-3GHz, 8-8.5GHz, 13.5-14GHz, 19-19.5GHz, and is amplified by the amplifier, and is modulated to the second optical pulse by the modulator.

[0077] 7) The second optical pulse down-converts the multi-band signal to 2-2.5GHz, 1.5-2GHz, 1-1.5GHz, 0.5-1GHz. After photoelectric conversion by the photodetector, it is filtered by the 0-2.5GHz low-pass filter.

[0078] 8) Adjust the second delay line and the second phase shifter so that Multi-band beamforming is achieved.

[0079] 9) The low-pass filter output is combined by the combiner and then converted to digital, and the multi-band signal reception is completed.

[0080] In the above process, the baseband signal is up-converted and down-converted by the optical pulse, and the phase adjustment of the multi-band signal is completed by adjusting the delay line and the phase shifter, and the multi-band beamforming is achieved.

[0081] Experiments show that the application can use the above-mentioned set of equipment (single link) to realize the generation, frequency conversion, phase shift and digitization of multi-band signals, and at the same time complete the coherent transmission and reception of multi-band signals. The above is only a preferred example of the application and is not used to limit the application. Any modification, equivalent replacement and improvement made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A multi-band shared phased array transceiver system based on optical pulses, characterized by, Comprise: A first light pulse generator, a second light pulse generator, a first modulator, a second modulator, a first coupler, a second coupler, a first delay line, a second delay line, an attenuator, a balanced photodetector, a photodetector, a low-pass filter, a first phase shifter, a second phase shifter, a combiner, a power divider, an analog-to-digital converter, a digital-to-analog converter, a first amplifier and a second amplifier; At the signal transmitting end: the first light pulse generator generates a first light pulse, which is adjusted in time delay by the first delay line and then divided into two paths, one of which is modulated by the baseband signal output by the digital-to-analog converter and phase-shifted by the first phase shifter to the first light pulse through the first modulator, and then input to the balanced photodetector after being up-converted to multiple frequency bands, and the other path is input to the balanced photodetector after the power of the first light pulse is adjusted by the attenuator, and the signals detected by the balanced photodetector after the two paths of the first light pulse are differentially detected are amplified by the first amplifier and then transmitted by the antenna array; the output end of the first light pulse generator is connected with the first coupler to provide the first light pulse for multiple phased array elements; the output end of the first coupler is connected with the input end of the first delay line; the output end of the first delay line is divided into upper and lower paths through a coupler, the upper path is connected with the optical input end of the first modulator, and the lower path is connected with the input end of the attenuator; the output end of the digital-to-analog converter is connected with the input end of the power divider, and the output end of the power divider is connected with the input end of the first phase shifter of multiple elements; the output end is connected with the radio frequency input end of the first modulator, and the optical output end of the first modulator is connected with the output end of the attenuator to the same direction input end and reverse input end of the balanced photodetector respectively; the output is connected with the input end of the first amplifier, and the output end of the first amplifier is connected with the antenna elements of the transmitting array antenna; At the signal receiving end: the second light pulse generator generates a second light pulse, which is adjusted in time delay by the second delay line and then modulated by the second modulator to the multi-band signal received by the antenna to realize down-conversion to the baseband, and then converts the optical signal to an electrical signal by the photodetector, filters and phase-shifts the electrical signal by the low-pass filter and the second phase shifter, and then quantizes the digital signal by the analog-to-digital converter; The output end of the second light pulse generator is connected with the coupler to provide the second light pulse for multiple phased array elements; the output of the coupler is connected with the input end of the second delay line; the output end of the second delay line is connected with the optical input end of the second modulator; the radio frequency input end of the second modulator is connected with the output end of the second amplifier; the input end of the second amplifier is connected with the antenna elements of the receiving antenna array; the optical output end of the second modulator is connected with the input end of the photodetector; the output end of the photodetector is connected with the input end of the low-pass filter; the output end of the low-pass filter is connected with the input end of the second phase shifter; the output end of the second phase shifter is connected with the input end of the combiner; the combiner combines the outputs of the second phase shifters of multiple elements into one path, and the output end of the combiner is connected with the input end of the analog-to-digital converter.

2. The optical pulse based multi-band shared phased array transceiver system of claim 1, wherein, The first phase shifter at the signal transmitting end is used to adjust the phase of the signal to realize beam forming of the multi-band signal.

3. The optical pulse based multi-band shared phased array transceiver system of claim 2, wherein, The first phase shifter and the second phase shifter are both digital phase shifters.

4. The optical pulse based multi-band shared phased array transceiver system of claim 2, wherein, Also included are a power divider for distributing the output signal of the digital-to-analog converter to the first phase shifters of the plurality of elements, and a power combiner for combining the received signals of the plurality of elements and inputting the combined signals to the analog-to-digital converter.

5. The optical pulse based multi-band shared phased array transceiver system of claim 1, wherein, The first optical pulse generator and the second optical pulse generator are each an actively mode-locked laser, a passively mode-locked laser, or an optical frequency comb generated based on an external modulation method.

6. The optical pulse based multi-band shared phased array transceiver system of claim 1, wherein, The first modulator and the second modulator are each a Mach-Zehnder intensity modulator, a lithium niobate electro-optic modulator, a polymer electro-optic modulator, a silicon-based integrated electro-optic modulator, an acousto-optic modulator, or a spatial light modulator.

7. The optical pulse based multi-band shared phased array transceiver system of claim 1, wherein, The first delay line and the second delay line are each an electrically driven delay line, a micro-ring delay line, or a delay line based on a high-order dispersion optical fiber.

8. A multi-band implementation method using the multi-band shared phased array transceiving system based on optical pulses according to any one of claims 1-7, characterized in that, The method comprises the following steps: ① The first optical pulse generator generates a first optical pulse at a signal transmitting end, and the second optical pulse generator generates a second optical pulse at a signal receiving end. ② At the signal transmitting end, a baseband signal output by a digital-to-analog converter is phase-shifted by a first phase shifter and modulated onto an optical pulse by a first modulator to realize up-conversion of the baseband signal to a plurality of frequency bands; meanwhile, another optical pulse is adjusted in power by an attenuator, differentially detected with the output of the first modulator, amplified, and then transmitted by an antenna array; ③ At the signal receiving end, a plurality of frequency band signals received by the antenna are amplified, modulated onto a second optical pulse by a second modulator to realize down-conversion to a baseband, and then converted into an electrical signal by a photoelectric detector, filtered by a low-pass filter, phase-shifted by a second phase shifter, and quantized into a digital signal by an analog-to-digital converter; ④ The first delay line, the second delay line, the first phase shifter, and the second phase shifter are adjusted to realize phase control of the plurality of frequency band signals in the transmitting and receiving processes, so as to ensure the coherence of the plurality of frequency band signals and the accuracy of beamforming. The center frequency f and the bandwidth B of the baseband signal generated by the digital-to-analog converter satisfy the following conditions: ​ 9. The multi-band implementation method of claim 8, wherein, ​ wherein f s1 is a repetition rate of the first optical pulses generated by the first optical pulse generator, s2 is a repetition rate of the second optical pulses generated by the second optical pulse generator, and 10. The multi-band implementation method of claim 8, wherein, The step ④ adjusts the delay At1 of the first delay line and the phase shift of the first phase shifter satisfies the following conditions: Alternatively, the delay At2 of the second delay line and the phase shift of the second phase shifter are adjusted satisfy the following conditions: All can realize multi-band phase shift and multi-band beam forming, complete multi-band signal generation and transmission; wherein, is the time difference between the transmitting end elements, is the time difference between the receiving end elements, and is the pulse period of the transmitting end optical pulse and the receiving end optical pulse.

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