A p / s cross-band wavefront reconfigurable multi-beam transmitting array system

Abstract

The application provides a P / S cross-band wave front reconfigurable multi-beam transmitting array system, comprising: an optical frequency comb generator generating optical frequency comb teeth with equal frequency intervals; an optical power divider equally dividing the optical frequency comb teeth into three paths; three Mach-Zehnder modulators performing carrier-suppressed double sideband modulation on the three paths of optical signals; two programmable photonic filters independently loading amplitude and phase weights on two paths of local oscillator positive first-order sidebands; two periodic narrowband filters filtering out the two paths of local oscillator positive first-order sidebands; an optical coupler combining the three paths of optical signals into one path; an optical demultiplexer demultiplexing the composite optical signal into multiple paths of optical signals; an optoelectronic conversion array outputting P-band and S-band transmitting electrical signals; and an antenna array simultaneously transmitting the double-band signals to free space. The application can realize cross-band simultaneous multi-beam transmission and wave front shape reconfiguration, and the system is flexible, stable and low in complexity.

Description

Technical Field

[0001] This invention relates to the field of microwave photonic array signal processing technology, and in particular to a P / S cross-band wavefront reconfigurable multi-beam transmitting array system. Background Technology

[0002] Phased array radar achieves beam scanning through electronic control, eliminating the need for mechanical antenna rotation. Its working principle involves controlling the phase difference between the transmitted and received signals from each antenna element in the array, causing electromagnetic waves to coherently superimpose in a specific direction, forming a directional beam. Compared to traditional mechanically scanned radar, phased array radar offers advantages such as microsecond-level rapid scanning, simultaneous multi-target tracking, and high reliability, making it a core piece of equipment in modern air defense early warning, missile defense, and 6G communications.

[0003] With increasingly complex battlefield environments and continuously growing communication demands, phased array systems face new technical challenges. On the one hand, the system needs to support wider operating bandwidth to meet the requirements of high-resolution detection and high-capacity communication; on the other hand, the system also needs to perform differentiated wavefront control for multiple frequency bands, multiple beams, and multiple users based on the dynamically changing electromagnetic environment to achieve functions such as active cognitive detection, interference avoidance, and electromagnetic silence. These functions require phased array systems not only to control the beam direction but also to reconstruct the wavefront shape, such as creating nulls in specific interference directions and achieving non-uniform amplitude weighting.

[0004] To meet these needs, various attempts have been made in existing technologies. Digital beamforming technology can flexibly control the beam pointing and shape by changing the digital weighting coefficients of each channel. However, this technology faces problems of high hardware cost and high data processing complexity: each array element requires an independent RF channel and a high sampling rate analog-to-digital converter module, resulting in significant system power consumption and signal processing delay, which is more pronounced in cross-frequency band and large-scale array scenarios. Microwave photonic true delay-based array signal processing technology has received widespread attention in recent years. This type of scheme uses photonic technology to achieve true delay compensation for broadband signals, which is not limited by signal bandwidth and can effectively solve the beam squinting problem in broadband phased arrays. However, most existing microwave photonic true delay phased array systems adopt a static architecture, which can only make the beam align in a single direction under specific parameter configurations, making it difficult to extend to more complex wavefront modulation modes. Specifically, these schemes usually use tunable optical delay lines to apply equal phase to each array element channel to achieve beam pointing scanning. This linear phase-weighted scheme can only control the beam pointing angle and cannot achieve nonlinear reconstruction of the wavefront shape, thus making it difficult to meet the needs of intelligent detection and information warfare in modern radar electronic warfare. Summary of the Invention

[0005] In view of this, embodiments of the present invention provide a P / S cross-band wavefront reconfigurable multi-beam transmitting array system to solve the problems of insufficient cross-band simultaneous multi-beam generation capability, inability to reconfigure wavefront shape, and difficulty in balancing system flexibility and complexity in the prior art.

[0006] On one hand, the present invention provides a P / S cross-band wavefront reconfigurable multi-beam transmitting array system, the system comprising: Optical frequency comb generator, used to generate coherent optical frequency comb teeth with multiple flat, equally spaced frequency teeth; An optical power divider, connected to the optical frequency comb generator, is used to divide the optical frequency comb teeth into three paths: a signal path, a P-band local oscillator path, and an S-band local oscillator path. A first Mach-Zehnder modulator is disposed on the signal path to receive intermediate frequency signals and operate in carrier suppression mode to perform carrier suppression double-sideband modulation on the optical frequency comb of the signal path. The second Mach-Zehnder modulator is located on the P-band local oscillator circuit. It is used to receive the first local oscillator signal whose frequency is the sum of the intermediate frequency signal frequency and the center frequency of the P-band. It operates in carrier suppression mode and performs carrier suppression double-sideband modulation on the optical frequency comb of the P-band local oscillator circuit. The third Mach-Zehnder modulator is located on the S-band local oscillator circuit. It is used to receive the second local oscillator signal, whose frequency is the sum of the intermediate frequency signal frequency and the center frequency of the S-band. It operates in carrier suppression mode and performs carrier suppression double-sideband modulation on the optical frequency comb of the S-band local oscillator circuit. A first programmable photonic filter is disposed on the P-band local oscillator and located after the second Mach-Zehnder modulator, and is used to independently apply amplitude weights and phase weights to the positive first-order sidebands corresponding to each optical frequency comb tooth of the P-band local oscillator. The second programmable photonic filter is disposed on the S-band local oscillator and located after the third Mach-Zehnder modulator. It is used to independently apply amplitude weights and phase weights to the positive first-order sidebands corresponding to each optical frequency comb tooth of the S-band local oscillator. A first periodic narrowband filter is disposed on the P-band local oscillator path and located after the first programmable photonic filter. Its free spectral range is consistent with the free spectral range of the optical frequency comb, and it is used to filter out the positive first-order sidebands of each optical frequency comb tooth of the P-band local oscillator path. The second periodic narrowband filter is disposed on the S-band local oscillator and located after the second programmable photonic filter. Its free spectral range is consistent with the free spectral range of the optical frequency comb, and it is used to filter out the positive first-order sidebands of each optical frequency comb tooth of the S-band local oscillator. An optical coupler is connected to the signal path, the output of the first periodic narrowband filter, and the output of the second periodic narrowband filter, respectively, and is used to combine the optical signal of the signal path, the filtered P-band local oscillator positive first-order sideband, and the filtered S-band local oscillator positive first-order sideband into a composite optical signal. A demultiplexer, connected to the optical coupler, has a transmission peak spacing that matches the free spectral range of the optical frequency comb. It is used to demultiplex the composite optical signal into multiple optical signals according to frequency, with each optical signal corresponding to one optical frequency comb tooth. The photoelectric conversion array includes multiple photodetectors, multiple dual-band filters, and multiple low-noise amplifiers. Each optical signal is sequentially converted by the corresponding photodetector, filtered by the dual-band filter, and amplified by the low-noise amplifier to output P-band and S-band transmitted electrical signals. The antenna array, comprising multiple antenna elements, is connected one-to-one with each output terminal of the photoelectric conversion array, and is used to simultaneously transmit the P-band and S-band transmitted electrical signals into free space, forming a dual-band multi-beam array with a reconfigurable wavefront.

[0007] In some embodiments of the present invention, the optical frequency comb generator is an intensity-phase cascaded electro-optic modulator, which generates multiple optical frequency comb teeth with controllable flatness by adjusting the phase relationship of the driving signal entering the modulator.

[0008] In some embodiments of the present invention, the first Mach-Zehnder modulator, the second Mach-Zehnder modulator and the third Mach-Zehnder modulator respectively control their bias voltage through loop feedback to make them operate at the minimum bias point in order to achieve carrier suppression state.

[0009] In some embodiments of the present invention, the first programmable photonic filter and the second programmable photonic filter are multi-channel optical waveguide type programmable filters, which are used to independently load amplitude weights and phase weights on the optical signals of each channel to achieve shape reconstruction of the transmitted wavefront.

[0010] In some embodiments of the present invention, the first periodic narrowband filter and the second periodic narrowband filter are Fabry-Perot resonators or microring resonators, whose free spectral range is equal to that of the optical frequency comb, whose passband width satisfies a positive first-order sideband and negative first-order sideband suppression ratio greater than 20dB, and whose transmission peak is aligned with the positive first-order sideband.

[0011] In some embodiments of the present invention, the dewavelength division multiplexer is an arrayed waveguide grating or a cascaded microring resonator, the number of its channels being equal to the number of the optical frequency comb teeth, and its transmission peak spacing being equal to the free spectral range of the optical frequency comb.

[0012] In some embodiments of the present invention, the passband of the dual-band filter simultaneously covers the center frequency of the P-band and the center frequency of the S-band, its 3dB passband width is greater than 50MHz, and its out-of-band rejection is greater than 20dB.

[0013] In some embodiments of the present invention, the element spacing of the antenna array satisfies the following condition to avoid grating lobes during P-band and S-band signal transmission: ; in, This indicates the element spacing of the antenna array; This represents the smaller of the wavelengths corresponding to the center frequencies of the P-band and S-band.

[0014] In some embodiments of the present invention, the amplitude weights and phase weights loaded by the first programmable photonic filter and the second programmable photonic filter are calculated using a subspace projection method to form a beam null in a specified direction; the calculation formula for the weight vector of the subspace projection method is as follows: ; in, This represents the weight vector of the subspace projection method; The projection matrix of the orthogonal complement space of the interference subspace; A steering vector representing the desired signal direction; This indicates the conjugate transpose.

[0015] In some embodiments of the present invention, the frequency of the first local oscillator signal is the sum of the intermediate frequency signal frequency and the center frequency of the P-band, wherein the center frequency of the P-band is 0.98 GHz; the frequency of the second local oscillator signal is the sum of the intermediate frequency signal frequency and the center frequency of the S-band, wherein the center frequency of the S-band is 3.7 GHz; and the free spectral range of the optical frequency comb is 25 GHz.

[0016] The P / S cross-band wavefront reconfigurable multi-beam transmitting array system provided by this invention has the following beneficial effects.

[0017] This invention replaces the traditional tunable optical delay line with a programmable photonic filter, enabling independent and arbitrary weighting of the amplitude and phase of each channel's signal. Traditional delay-line-based schemes can only apply equal phase differences to each channel, essentially controlling only the beam pointing angle and unable to alter the beam shape. In contrast, this invention, through the flexible weighting capability of the programmable photonic filter, not only achieves precise beam pointing control but also allows for arbitrary reconstruction of the wavefront shape, such as creating deep nulls in specific interference directions and implementing complex functions like non-uniform amplitude shaping.

[0018] This invention employs a three-channel carrier-suppressed double-sideband modulation architecture with parallel signal and dual local oscillator paths. Combined with optical beat frequency in the photoelectric detection process, it achieves simultaneous generation and independent control of P-band and S-band transmitted signals. Each of the two local oscillators is loaded with its own wavefront weight, allowing the P-band and S-band beams to independently point in different directions and form wavefronts of different shapes, fully meeting the differentiated needs of multi-user, multi-task applications across bands. Simultaneously, the three signals originate from the same set of coherent optical frequency combs, ensuring a strict frequency locking relationship and guaranteeing the phase stability of beamforming.

[0019] This invention is based on a photonic channelization architecture using optical frequency combs and demultiplexing, concentrating the generation, transmission, and processing of multi-channel signals in the optical domain, with each channel sharing the same light source and control devices. Compared to digital beamforming technology, it eliminates the need for independent RF channels and high-sampling-rate analog-to-digital converters for each array element, significantly reducing system hardware costs and power consumption. Compared to traditional multi-channel independent control schemes, it avoids the synchronization complexity and random jitter caused by a large number of control units, resulting in higher system stability and lower complexity.

[0020] Furthermore, the system architecture of this invention has good scalability. By increasing the number of optical frequency comb teeth, the number of dewavelength division multiplexer channels, and the number of antenna array elements, the array size can be expanded to obtain narrower beams and higher spatial resolution. By replicating the local oscillator channel and designing corresponding frequency parameters, the system can be expanded to more frequency bands, enabling simultaneous multi-band, multi-beam transmission. In addition to the subspace projection method, other beamforming algorithms are also applicable to this invention, which can meet the wavefront reconstruction requirements in different scenarios.

[0021] Additional advantages, objects, and features of the invention will be set forth in part in the description which follows, and will also become apparent in part to those skilled in the art upon studying the description, or may be learned by practice of the invention. The objects and other advantages of the invention can be realized and obtained by means of the structures specifically pointed out in the description and drawings.

[0022] Those skilled in the art will understand that the objectives and advantages achievable with the present invention are not limited to those specifically described above, and that the above and other objectives achievable with the present invention will become clearer from the following detailed description. Attached Figure Description

[0023] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, are not intended to limit the scope of the invention. In the drawings: Figure 1 This is a schematic diagram of the composition structure of a P / S cross-band wavefront reconfigurable multi-beam transmission array system in one embodiment of the present invention.

[0024] Figure 2 This is a spectrum diagram of the output signal of a channel-1 photodetector in one embodiment of the present invention.

[0025] Figure 3 This is a graph showing the amplitude and phase curves of the output signals of each channel in one embodiment of the present invention. The left graph shows the power and phase curves of the P-band, and the right graph shows the power and phase curves of the S-band.

[0026] Figure 4 This is a comparison of the spatial energy distribution patterns of one embodiment of the present invention and conventional beamforming. The left image shows a comparison of the P-band pattern, and the right image shows a comparison of the S-band pattern. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments and accompanying drawings. Here, the illustrative embodiments and descriptions of this invention are used to explain the invention, but are not intended to limit the invention.

[0028] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0029] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, element, step, or component, but does not exclude the presence or addition of one or more other features, elements, steps, or components.

[0030] It should also be noted that, unless otherwise specified, the term "connection" in this article can refer not only to a direct connection, but also to an indirect connection involving an intermediary.

[0031] In the following description, embodiments of the invention will be illustrated with reference to the accompanying drawings. In the drawings, the same reference numerals represent the same or similar parts, or the same or similar steps.

[0032] It should be emphasized here that the step markers mentioned below are not a limitation on the order of the steps, but should be understood as meaning that the steps can be executed in the order mentioned in the embodiments, or in a different order than in the embodiments, or several steps can be executed simultaneously.

[0033] To address the shortcomings of existing technologies, such as insufficient cross-band simultaneous multi-beam generation capability, inability to reconfigure wavefront shapes, and difficulty in balancing system flexibility and complexity, this invention provides a P / S cross-band wavefront reconfigurable multi-beam transmission array system, such as... Figure 1 As shown, the system includes: An optical frequency comb generator is used to produce coherent optical frequency comb teeth with multiple flat, equally spaced frequency teeth.

[0034] The optical power divider, connected to the optical frequency comb generator, is used to divide the optical frequency comb teeth into three paths: the signal path, the P-band local oscillator path, and the S-band local oscillator path.

[0035] The first Mach-Zehnder modulator is located on the signal path and is used to receive intermediate frequency signals and operate in carrier suppression mode to perform carrier suppression double-sideband modulation on the optical frequency comb of the signal path.

[0036] The second Mach-Zehnder modulator is located on the P-band local oscillator circuit. It is used to receive the first local oscillator signal, whose frequency is the sum of the intermediate frequency signal frequency and the center frequency of the P-band. It operates in carrier suppression mode and performs carrier suppression double-sideband modulation on the optical frequency comb of the P-band local oscillator circuit.

[0037] The third Mach-Zehnder modulator, located on the S-band local oscillator, is used to receive the second local oscillator signal whose frequency is the sum of the intermediate frequency signal frequency and the S-band center frequency. It operates in carrier suppression mode and performs carrier suppression double-sideband modulation on the optical frequency comb of the S-band local oscillator.

[0038] The first programmable photonic filter, located on the P-band local oscillator and after the second Mach-Zehnder modulator, is used to independently apply amplitude and phase weights to the positive first-order sidebands corresponding to each optical frequency comb tooth of the P-band local oscillator.

[0039] The second programmable photonic filter, located on the S-band local oscillator and after the third Mach-Zehnder modulator, is used to independently apply amplitude and phase weights to the positive first-order sidebands corresponding to each optical frequency comb tooth of the S-band local oscillator.

[0040] The first periodic narrowband filter is set on the P-band local oscillator and located after the first programmable photonic filter. Its free spectral range is consistent with the free spectral range of the optical frequency comb. It is used to filter out the positive first-order sidebands of each optical frequency comb tooth of the P-band local oscillator.

[0041] The second periodic narrowband filter is set on the S-band local oscillator path and located after the second programmable photonic filter. Its free spectral range is consistent with the free spectral range of the optical frequency comb, and it is used to filter out the positive first-order sidebands of each optical frequency comb tooth of the S-band local oscillator path.

[0042] An optical coupler is connected to the signal path, the output of the first periodic narrowband filter, and the output of the second periodic narrowband filter, respectively, and is used to combine the optical signal of the signal path, the filtered P-band local oscillator positive first-order sideband, and the filtered S-band local oscillator positive first-order sideband into a composite optical signal.

[0043] The demultiplexer, connected to the optical coupler, has a transmission peak spacing that matches the free spectral range of the optical frequency comb. It is used to demultiplex composite optical signals into multiple optical signals according to frequency, with each optical signal corresponding to one optical frequency comb tooth.

[0044] The photoelectric conversion array includes multiple photodetectors, multiple dual-band filters, and multiple low-noise amplifiers. Each optical signal is sequentially converted by the corresponding photodetector, filtered by the dual-band filter, and amplified by the low-noise amplifier to output P-band and S-band transmitted electrical signals.

[0045] The antenna array, comprising multiple antenna elements, is connected one-to-one with each output terminal of the photoelectric conversion array. It is used to simultaneously transmit P-band and S-band electrical signals into free space, forming a dual-band multi-beam array with a reconfigurable wavefront.

[0046] The following describes each piece of hardware in the P / S cross-band wavefront reconfigurable multi-beam transmitter array system.

[0047] Optical frequency comb generators are used to produce coherent optical frequency comb teeth with multiple flat, equally spaced frequency teeth.

[0048] In some embodiments, the optical frequency comb generator is implemented using an intensity-phase cascaded electro-optic modulator. Specifically, by applying a radio frequency drive signal with a specific phase relationship to the cascaded intensity modulator and phase modulator, multiple coherent optical frequency comb teeth with controllable flatness can be generated. The frequency of the drive signal determines the free spectral range (FSR) of the optical frequency comb, that is, the frequency spacing between adjacent optical frequency comb teeth.

[0049] In some embodiments, a 25 GHz radio frequency source is used to drive the optical frequency comb generator, such that the frequency interval between adjacent optical frequency comb teeth is 25 GHz, and at least 16 optical frequency comb teeth with good flatness can be generated.

[0050] The multi-wavelength coherent optical carriers generated by the optical frequency comb generator are the foundation for multi-channel parallel processing in this invention. Each optical frequency comb tooth corresponds to an element channel in the antenna array. Through subsequent channelization processing, the signals of each channel can be transmitted and processed in parallel in the optical domain, thus avoiding the high cost and complexity of configuring an independent RF channel for each element in traditional phased arrays. At the same time, the strict frequency locking relationship between the optical frequency comb teeth ensures the coherence of the signals in each channel, providing phase stability for subsequent precise beamforming.

[0051] like Figure 1 As shown, the output of the optical frequency comb generator is connected to the optical power divider. The optical power divider is used to divide the multiple optical frequency comb teeth generated by the optical frequency comb generator into three paths: a signal path, a P-band local oscillator path, and an S-band local oscillator path.

[0052] In some embodiments, the optical power divider is implemented using a 1×3 fiber coupler or a planar waveguide type optical power divider with a splitting ratio of 1:1:1 to ensure that the power of the three optical signals is equal, thereby ensuring that the input optical power of each subsequent modulator is consistent.

[0053] The three optical signals carry different information: the signal path is used to load the intermediate frequency signal, while the P-band and S-band local oscillator paths are used to load local oscillator signals from two different frequency bands, respectively. By separating the signal from the local oscillator in the optical domain, this invention achieves parallel optical processing of cross-band signals, providing an architectural foundation for subsequent independent control of the P-band and S-band wavefronts. Simultaneously, the three optical signals originate from the same set of coherent optical frequency combs, ensuring a strict frequency locking relationship, which is a prerequisite for generating stable and pure P-band and S-band beat frequency signals during subsequent photoelectric detection.

[0054] The first Mach-Zehnder modulator is used to receive intermediate frequency signals and operates in carrier-suppressed mode to perform carrier-suppressed double-sideband modulation on the optical frequency comb of the signal path.

[0055] In some embodiments, the first Mach-Zehnder modulator controls its bias voltage through a loop feedback circuit, enabling it to operate precisely at the minimum bias point, thereby achieving carrier suppression. In this operating state, the optical carrier component in the optical signal output by the modulator is suppressed, retaining only the positive and negative first-order sideband components.

[0056] In some embodiments, the frequency of the input intermediate frequency signal is set to 7 GHz.

[0057] The second Mach-Zehnder modulator is used to receive the first local oscillator signal and operates in carrier-suppressed mode, performing carrier-suppressed double-sideband modulation on the optical frequency comb of the P-band local oscillator path. The frequency of the first local oscillator signal is the sum of the intermediate frequency signal frequency and the P-band center frequency.

[0058] In some embodiments, the intermediate frequency signal is set to 7 GHz, the P-band center frequency is set to 0.98 GHz, and therefore the frequency of the first local oscillator signal is 7.98 GHz.

[0059] Similar to the first Mach-Zehnder modulator, the second Mach-Zehnder modulator also controls its bias voltage through a loop feedback circuit, so that it operates precisely at the minimum bias point, thereby achieving carrier suppression.

[0060] The third Mach-Zehnder modulator is used to receive the second local oscillator signal and operates in carrier-suppressed mode, performing carrier-suppressed double-sideband modulation on the optical frequency comb of the S-band local oscillator path. The frequency of the second local oscillator signal is the sum of the intermediate frequency signal frequency and the S-band center frequency.

[0061] In some embodiments, the intermediate frequency signal is set to 7 GHz, the P-band center frequency is set to 3.7 GHz, and therefore the frequency of the second local oscillator signal is 10.7 GHz.

[0062] Similar to the aforementioned Mach-Zehnder modulator, the third Mach-Zehnder modulator also controls its bias voltage through a loop feedback circuit, enabling it to operate precisely at the minimum bias point and achieve carrier suppression.

[0063] In the subsequent photoelectric detection stage, the positive first-order sideband of the signal path will beat with the positive first-order sidebands of the P-band local oscillator and the S-band local oscillator, respectively. Since the three signals share the same set of optical frequency combs, the frequency of the radio frequency signal generated by the beat frequency is exactly the center frequency of the P-band and the center frequency of the S-band, thus realizing optical down-conversion transmission.

[0064] like Figure 1 As shown, a first programmable photonic filter is located on the P-band local oscillator after the second Mach-Zehnder modulator. A second programmable photonic filter is located on the S-band local oscillator after the third Mach-Zehnder modulator.

[0065] The first and second programmable photonic filters are used to independently apply amplitude and phase weights to the positive first-order sidebands corresponding to each optical frequency comb tooth in each local oscillator path. Unlike the existing technology that uses adjustable optical delay lines to apply only equal-aberration phase (i.e., linear phase), the programmable photonic filters used in this invention can independently apply arbitrary amplitude and phase weights to each channel, thereby realizing the shape reconstruction of the transmitted wavefront.

[0066] In some embodiments, the first programmable photonic filter and the second programmable photonic filter are implemented using multi-channel optical waveguide-type programmable filters (such as Waveshaper). Such devices can independently modulate the amplitude and phase of each frequency component of the input optical signal, offering advantages such as high resolution, flexible tuning, and strong programmability.

[0067] The core principle of wavefront reconstruction achieved by the present invention through a programmable photonic filter is as follows.

[0068] Because the optical frequency comb teeth have a strict equal frequency spacing characteristic, when the optical signal of the local oscillator path passes through the programmable photonic filter, the amplitude and phase weights applied by the filter to the positive first-order sidebands corresponding to each comb tooth will be mapped onto the amplitude and phase of the radio frequency signal transmitted by each antenna element through the subsequent photoelectric conversion process. Therefore, by reasonably designing the weights applied to each comb tooth, arbitrary reconstruction of the transmitted wavefront can be achieved.

[0069] In some embodiments, to achieve specific wavefront reconstruction goals, such as forming a main lobe in the desired direction and a null in the interference direction, this invention employs a subspace projection method as the beamforming algorithm to calculate the aforementioned weight vectors. The core idea of ​​the subspace projection method is to utilize the orthogonality principle of signal space. By constructing a subspace spanned by the interference signal steering vector, calculating the orthogonal complement projection matrix of this subspace, and projecting the initial static beam weight vector onto this orthogonal complement space, the components related to the interference direction in the weights are eliminated. This method can effectively suppress the transmitted signal in that direction while ensuring the main lobe gain in the desired signal direction and forming a deep null in a specific beam direction.

[0070] In some embodiments, the calculation process of the subspace projection method includes: First, let's assume we use a... A uniform linear array composed of n elements, with an element spacing of 1. There exists a desired azimuth angle. and One suppression azimuth angle ,in, The expression for the guiding vector is shown in formula (1): ; (1) in, Indicates the guide vector; Indicates the beam direction angle; Indicates the spacing between array elements; Indicates wavelength; Represents the imaginary unit; Indicates the number of array elements; This indicates transpose.

[0071] To suppress signals from a specific direction, an interference steering matrix is ​​first constructed, as shown in formula (2): ; (2) in, Represents the interference steering matrix; Indicates the first One interference direction angle; Indicates the number of interference directions.

[0072] The linear space spanned by the column vectors of the interference steering matrix is ​​called the interference subspace. The projection matrix of this subspace is defined by formula (3): ; (3) in, Represents the projection matrix of the interference subspace; This indicates the conjugate transpose.

[0073] To eliminate interference components, an orthogonal complement projection matrix of the interference subspace needs to be constructed. According to the principle of orthogonal projection, the orthogonal complement projection matrix can be expressed as the difference between the identity matrix and the interference projection matrix, as shown in formula (4): ; (4) in, Represents the projection matrix of the orthogonal complement space; express An identity matrix of order 1.

[0074] The initial static beam weight vector is set, usually taken as the steering vector of the desired signal direction. The initial static beam weight vector is orthogonally projected using the orthogonal complement spatial projection matrix to obtain the anti-interference weight vector, as shown in formula (5): ; (5) in, Represents the anti-interference weight vector; This represents the initial static beam weight vector.

[0075] At this point, the anti-interference weight vector is orthogonal to the interference subspace, which satisfies the following formula (6): ; (6) in, This represents the conjugate transpose of the anti-interference weight vector.

[0076] This means that the gain of the array pattern is zero in all directions to be suppressed, i.e., a deep null trap is formed. To ensure the main lobe gain in the desired signal direction, the weight vector needs to be normalized so that the gain in the desired direction is 1 (0dB). The final beamforming weights are shown in formula (7): ; (7) in, This represents the final beamforming weight vector; Indicates the steering vector of the desired signal direction; Indicates the desired signal direction angle; This represents the conjugate transpose of the desired signal direction steering vector.

[0077] By loading the calculated weight vector into the first programmable photonic filter and the second programmable photonic filter, the system can effectively suppress emission signals in other specific directions in the spatial domain while maintaining the emission intensity in the target direction, thereby reconstructing the wavefront shape.

[0078] like Figure 1As shown, a first periodic narrowband filter is provided on the P-band local oscillator line after the first programmable photonic filter; a second periodic narrowband filter is provided on the S-band local oscillator line after the second programmable photonic filter.

[0079] The first and second periodic narrowband filters are used to filter out the positive first-order sidebands corresponding to each optical frequency comb tooth in each local oscillator path, while suppressing the negative first-order sidebands and residual carrier components. The free spectral ranges of the two periodic narrowband filters are consistent with the free spectral range of the optical frequency comb to ensure that the positive first-order sidebands of each comb tooth can accurately pass through the transmission peak of the filter.

[0080] In some embodiments, the first periodic narrowband filter and the second periodic narrowband filter are implemented using a Fabry-Perot resonator or a microring resonator.

[0081] In some embodiments, a Fabry-Perot resonator is used to implement a periodic narrowband filter. The free spectral range of the filter is set to 25 GHz, which is consistent with the free spectral range of the optical frequency comb; its 3 dB bandwidth is 1 GHz, the passband width meets the requirement that the positive first-order sideband and negative first-order sideband suppression ratio is greater than 20 dB, and the transmission peak is aligned with the positive first-order sideband.

[0082] After the first and second programmable photonic filters perform amplitude and phase weighting on the positive first-order sidebands of each comb tooth, the optical signals of each local oscillator still simultaneously contain positive first-order sidebands, negative first-order sidebands, and residual carrier components. Among them, the negative first-order sidebands and residual carrier components will generate unwanted beat frequency components in the subsequent photodetector process, causing spectral spuriousness in the output signal and affecting the purity of the transmitted signal.

[0083] The function of a periodic narrowband filter is precisely to filter out these unwanted frequency components. Since the free spectral range of the filter is exactly equal to that of the optical frequency comb, the positive first-order sidebands of each comb tooth fall precisely at the center of each transmission peak of the filter, thus passing through the filter with minimal insertion loss. The negative first-order sidebands and residual carrier components fall within the filter's stopband and are effectively suppressed. By rationally designing the filter's passband width and stopband suppression, the suppression ratio of the positive and negative first-order sidebands can be greater than 20 dB, thereby significantly improving the spectral purity of the subsequent photoelectric detection output signal.

[0084] After being filtered by the first and second periodic narrowband filters, the optical signals output from the P-band and S-band local oscillator paths contain only the positive first-order sidebands of each comb tooth, carrying the wavefront weight information of the P-band and S-band, respectively. These two optical signals are then combined with the optical signal from the signal path (containing the positive and negative first-order sidebands of the signal path) into the optical coupler to form a composite optical signal. Since the negative first-order sideband and residual carrier of the local oscillator path have been filtered out, the frequency components in the composite optical signal are effectively purified, laying a good foundation for subsequent demultiplexing and photoelectric conversion.

[0085] like Figure 1 As shown, the optical coupler is connected to the signal path, the output of the first periodic narrowband filter, and the output of the second periodic narrowband filter, respectively, and is used to combine the optical signal of the signal path, the filtered P-band local oscillator positive first-order sideband, and the filtered S-band local oscillator positive first-order sideband into a composite optical signal.

[0086] Specifically, the optical coupler has three input ports and one output port. The first input port receives the optical signal output from the first Mach-Zehnder modulator of the signal path, which contains the positive and negative first-order sidebands of each optical frequency comb tooth of the signal path. The second input port receives the P-band local oscillator optical signal output from the first periodic narrowband filter, which contains only the positive first-order sidebands of each optical frequency comb tooth of the P-band local oscillator, and each positive first-order sideband has been loaded with amplitude and phase weights for wavefront reconstruction. The third input port receives the S-band local oscillator optical signal output from the second periodic narrowband filter, which contains only the positive first-order sidebands of each optical frequency comb tooth of the S-band local oscillator, and has also been loaded with corresponding amplitude and phase weights. The optical coupler combines these three optical signals into a single composite optical signal and outputs it from its output port.

[0087] In some embodiments, the optical coupler is implemented using a fiber optic coupler or a planar waveguide type optical coupler.

[0088] By combining the information from each channel with an optical coupler, the information is converged into a single optical fiber for transmission. The subsequent demultiplexer then completes the physical separation of all channels at once, enabling the simultaneous transmission of optical signals from the signal path, P-band local oscillator path, and S-band local oscillator path in a single optical link. This simplifies the system architecture and reduces hardware costs.

[0089] like Figure 1 As shown, the demultiplexer is connected to the output of the optical coupler and is used to demultiplex the composite optical signal into multiple optical signals according to the frequency. Each optical signal corresponds to an optical frequency comb.

[0090] The transmission peak spacing of the demultiplexer is consistent with the free spectral range of the optical frequency comb, and the number of its channels is equal to the number of optical frequency comb teeth. This means that the nth output port of the demultiplexer only transmits optical signals with a center frequency equal to the frequency of the nth optical frequency comb tooth, while effectively isolating optical signals of other frequencies.

[0091] In some embodiments, the dewavelength division multiplexer is implemented using an arrayed waveguide grating or a cascaded microring resonator.

[0092] In some embodiments, the channel spacing of the demultiplexer is set to 25 GHz, consistent with the free spectral range of the optical frequency comb; the channel bandwidth is 12 GHz, sufficient to accommodate the various order sidebands of the signal path and the local oscillator path; and the number of channels is 16, consistent with the number of optical frequency comb teeth, photodetectors, and antenna array elements.

[0093] After being combined by an optical coupler, the composite optical signal contains multiple frequency components corresponding to all optical frequency comb teeth, specifically: the positive and negative first-order sidebands of the signal path, the positive first-order sideband of the P-band local oscillator path, and the positive first-order sideband of the S-band local oscillator path. These frequency components are transmitted mixed in a single optical fiber and cannot be directly fed into individual antenna elements. The function of the dewavelength division multiplexer is to separate these mixed frequency components according to their respective optical frequency comb teeth, routing all frequency components corresponding to the nth optical frequency comb tooth to the nth output channel, thereby establishing a one-to-one correspondence between the optical frequency comb teeth and the physical channels.

[0094] It should be noted that the number of channels in the demultiplexer is consistent with the number of optical frequency comb teeth, the number of photodetectors, and the number of antenna array elements. Specifically, each tooth of the optical frequency comb corresponds to one antenna element channel. The demultiplexer separates the optical signal corresponding to each comb tooth into an independent physical channel. The optical signal of each channel drives the corresponding antenna element after photoelectric conversion. This one-to-one correspondence design ensures that the phase relationship between the signals in each channel is accurately maintained during transmission and processing, which is the foundation for achieving precise beamforming.

[0095] like Figure 1 As shown, the photoelectric conversion array includes multiple photodetectors, multiple dual-band filters, and multiple low-noise amplifiers. The number of channels in the photoelectric conversion array is the same as the number of channels in the dewavelength division multiplexer. Each optical signal sequentially undergoes photoelectric conversion by the corresponding photodetector, filtering by the dual-band filter, and amplification by the low-noise amplifier, outputting P-band and S-band transmitted electrical signals.

[0096] Each photodetector's input terminal is connected to the corresponding output port of the demultiplexer to convert the input optical signal into an electrical signal. The photodetector uses a square-law detection method, and the output photocurrent is proportional to the input optical power. When multiple optical signals of different frequencies are simultaneously incident on the photodetector, the detector outputs an electrical signal containing the difference frequency components between these optical frequencies.

[0097] Specifically, the photodetector beats three frequency components: the positive first-order sideband of the input signal path, the positive first-order sideband of the P-band local oscillator path, and the positive first-order sideband of the S-band local oscillator path, generating the following difference frequency components: (1) The first-order sideband of the signal path beats the first-order sideband of the P-band local oscillator path to generate a P-band signal. Since the two optical signals come from the same optical frequency comb, their phase difference is determined by the weights loaded by the programmable photonic filter. Therefore, the P-band signal carries the corresponding wavefront weight information.

[0098] (2) The first-order sideband of the signal path beats with the first-order sideband of the S-band local oscillator path to generate an S-band signal. Similarly, this S-band signal carries the corresponding wavefront weight information.

[0099] (3) Combinations such as the negative first-order sideband of the signal path and the positive first-order sideband of the P-band local oscillator path, and the negative first-order sideband of the signal path and the positive first-order sideband of the S-band local oscillator path will also generate beat frequency components. However, the frequencies of these components are usually high or low and can be suppressed by subsequent dual-band filters.

[0100] In some embodiments, the P-band signal frequency is 0.98 GHz and the S-band signal frequency is 3.7 GHz. For example... Figure 2 As shown, the signal at 0.98 GHz in the P-band and the signal at 3.7 GHz in the S-band can be clearly observed in the spectrum output by the photodetector.

[0101] The input of each dual-band filter is connected to the output of the corresponding photodetector to filter the electrical signal output by the photodetector. The passband of the dual-band filter covers both the center frequency of the P-band and the center frequency of the S-band, with a 3dB passband width greater than 50MHz and out-of-band rejection greater than 20dB.

[0102] The function of a dual-band filter is to extract the target P-band and S-band signals while suppressing other stray components generated during photoelectric detection. Since the passband of a dual-band filter covers both the P-band and S-band, a single filter can perform the filtering task for both bands, simplifying the system structure.

[0103] The input terminals of each low-noise amplifier are connected to the output terminals of the corresponding dual-band filters to amplify the filtered P-band and S-band signals.

[0104] After being processed by the photoelectric conversion array, the P-band and S-band electrical signals output from each channel carry amplitude weights and phase weights loaded by the first programmable photonic filter and the second programmable photonic filter, respectively.

[0105] like Figure 3 As shown, in one specific embodiment, when the P-band is set to transmit at 0° and suppress at -47°, and the S-band is set to transmit at 0° and suppress at 20°, the power and phase curves of the output signals of each channel exhibit a specific distribution. These amplitude and phase distributions are precisely the weight vectors required to achieve wavefront reconstruction, and are accurately loaded into the transmitted signals of each channel.

[0106] like Figure 1 As shown, the antenna array includes multiple antenna elements, which are connected one-to-one with each output terminal of the photoelectric conversion array. It is used to simultaneously transmit P-band and S-band electrical signals into free space, forming a dual-band multi-beam array with a reconfigurable wavefront.

[0107] The number of antenna elements is consistent with the number of optical frequency comb teeth, the number of dewavelength division multiplexer channels, and the number of photoelectric conversion array channels. The nth antenna element is connected to the output of the nth photoelectric conversion channel, receives the P-band and S-band transmitted electrical signals output by that channel, and converts them into electromagnetic waves radiated into free space.

[0108] In some embodiments, the antenna elements are arranged in a one-dimensional uniform linear array with equal spacing. The element spacing design needs to simultaneously meet the requirement of not generating grating lobes at the wavelengths of P-band and S-band signals. Grating lobes are additional beams that appear in the array antenna in addition to the main lobe, which will cause energy dispersion and pattern blurring. To avoid the generation of grating lobes, the element spacing should meet the following conditions, as shown in formula (8): ; (8) in, This represents the smaller of the wavelengths corresponding to the center frequencies of the P-band and S-band.

[0109] When the signals fed into each element of the antenna array have specific amplitude and phase distributions, the electromagnetic waves radiated by each element coherently superimpose in space. In the desired direction, the electromagnetic waves radiated by each element have the same phase, and their amplitude is enhanced after superposition, forming the main lobe of the beam. In the undesired direction, the electromagnetic waves radiated by each element have different phases, canceling each other out and reducing energy. By adjusting the amplitude and phase weights of the signals in each channel, the direction and shape of the beam can be controlled.

[0110] In this invention, the amplitude and phase weights of each channel signal are loaded by a first programmable photonic filter and a second programmable photonic filter, and then transmitted to the transmitted signals of each antenna element via a photoelectric conversion array. Therefore, by designing the weight vector of the programmable photonic filter, precise control of the transmitted beam can be achieved.

[0111] It should be noted that, in this invention, wavefront reconfigurability refers to the ability to flexibly reconstruct the wavefront shape of the transmitted beam by changing the weight vector of the programmable photonic filter, rather than being limited to traditional single-point scanning. Specifically, wavefront reconfigurability includes the following two aspects: First, the beam pointing is adjustable. By applying linearly increasing phase weights to each channel, the beam can be pointed in the desired direction.

[0112] Second, the beam shape is reconfigurable. By applying non-uniform amplitude weights and non-linear phase weights to each channel, nulls (i.e., regions where emitted energy is effectively suppressed) can be formed in specific directions, or other complex beam shapes can be achieved. This invention achieves this function by calculating the weight vector through beamforming algorithms such as subspace projection and precisely loading it with a programmable photonic filter.

[0113] In a specific embodiment of the present invention, the amplitude weight and phase weight of each channel are calculated using the subspace projection method and then loaded into a programmable photonic filter. For example... Figure 4 As shown, the measured beam pattern indicates that: For the P-band, the system achieved beam pointing at 0° while simultaneously creating a deep null at -47°. Compared to conventional beamforming (which only controls pointing without null suppression), the gain attenuation at -47° was improved by nearly 30 dB.

[0114] For the S-band, the system achieved beam pointing at 0° while simultaneously creating a deep null at 20°. Similarly, the suppression at 20° was nearly 30 dB better than conventional beamforming.

[0115] The above results fully verify that the present invention possesses the capability of simultaneous multi-beam transmission across bands and wavefront reconfiguration. The system can maintain transmission intensity in the target direction while forming deep nulls in specific interference directions, achieving intelligent transmission beam control.

[0116] Furthermore, the P / S cross-band wavefront reconfigurable multi-beam transmission array system architecture provided by this invention has good scalability and is not limited to the demonstrated P / S band, specific reconstruction angle, and subspace projection method. On the one hand, by expanding the number of comb teeth of the optical frequency comb, increasing the number of channels of the demultiplexer, and the number of antenna array elements, the array size of the system can be expanded to obtain narrower beams and higher spatial resolution. On the other hand, by replicating more local oscillator channels and designing corresponding frequency parameters, the system can be expanded to more frequency bands (such as L-band, C-band, X-band, etc.) to achieve simultaneous multi-band multi-beam transmission. In addition, besides the subspace projection method, other beamforming algorithms, such as the minimum variance distortionless response algorithm and the linearly constrained minimum variance algorithm, can also be applied to this invention to achieve different wavefront reconstruction effects.

[0117] Corresponding to the above method, the present invention also provides an electronic device including a computer device, the computer device including a processor and a memory, the memory storing computer instructions, the processor executing the computer instructions stored in the memory, and when the computer instructions are executed by the processor, the electronic device performs the steps of the method as described above.

[0118] This invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the aforementioned method. The computer-readable storage medium may be a tangible storage medium, such as random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, register, floppy disk, hard disk, removable storage disk, CD-ROM, or any other form of storage medium known in the art.

[0119] Those skilled in the art will understand that the exemplary components, systems, and methods described in conjunction with the embodiments disclosed herein can be implemented in hardware, software, or a combination of both. Whether implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this invention. When implemented in hardware, it can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this invention are programs or code segments used to perform the desired tasks. The programs or code segments can be stored in a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried in a carrier wave.

[0120] It should be clarified that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of the present invention.

[0121] In this invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with or in place of features of other embodiments.

[0122] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations of the embodiments of the present invention are possible. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A P / S cross-band wavefront reconfigurable multi-beam transmitting array system, characterized in that, The system includes: Optical frequency comb generator, used to generate coherent optical frequency comb teeth with multiple flat, equally spaced frequency teeth; An optical power divider, connected to the optical frequency comb generator, is used to divide the optical frequency comb teeth into three paths: a signal path, a P-band local oscillator path, and an S-band local oscillator path. A first Mach-Zehnder modulator is disposed on the signal path to receive intermediate frequency signals and operate in carrier suppression mode to perform carrier suppression double-sideband modulation on the optical frequency comb of the signal path. The second Mach-Zehnder modulator is located on the P-band local oscillator circuit. It is used to receive the first local oscillator signal whose frequency is the sum of the intermediate frequency signal frequency and the center frequency of the P-band. It operates in carrier suppression mode and performs carrier suppression double-sideband modulation on the optical frequency comb of the P-band local oscillator circuit. The third Mach-Zehnder modulator is located on the S-band local oscillator circuit. It is used to receive the second local oscillator signal, whose frequency is the sum of the intermediate frequency signal frequency and the center frequency of the S-band. It operates in carrier suppression mode and performs carrier suppression double-sideband modulation on the optical frequency comb of the S-band local oscillator circuit. A first programmable photonic filter is disposed on the P-band local oscillator and located after the second Mach-Zehnder modulator, and is used to independently apply amplitude weights and phase weights to the positive first-order sidebands corresponding to each optical frequency comb tooth of the P-band local oscillator. The second programmable photonic filter is disposed on the S-band local oscillator and located after the third Mach-Zehnder modulator. It is used to independently apply amplitude weights and phase weights to the positive first-order sidebands corresponding to each optical frequency comb tooth of the S-band local oscillator. A first periodic narrowband filter is disposed on the P-band local oscillator path and located after the first programmable photonic filter. Its free spectral range is consistent with the free spectral range of the optical frequency comb, and it is used to filter out the positive first-order sidebands of each optical frequency comb tooth of the P-band local oscillator path. The second periodic narrowband filter is disposed on the S-band local oscillator and located after the second programmable photonic filter. Its free spectral range is consistent with the free spectral range of the optical frequency comb, and it is used to filter out the positive first-order sidebands of each optical frequency comb tooth of the S-band local oscillator. An optical coupler is connected to the signal path, the output of the first periodic narrowband filter, and the output of the second periodic narrowband filter, respectively, and is used to combine the optical signal of the signal path, the filtered P-band local oscillator positive first-order sideband, and the filtered S-band local oscillator positive first-order sideband into a composite optical signal. A demultiplexer, connected to the optical coupler, has a transmission peak spacing that matches the free spectral range of the optical frequency comb. It is used to demultiplex the composite optical signal into multiple optical signals according to frequency, with each optical signal corresponding to one optical frequency comb tooth. The photoelectric conversion array includes multiple photodetectors, multiple dual-band filters, and multiple low-noise amplifiers. Each optical signal is sequentially converted by the corresponding photodetector, filtered by the dual-band filter, and amplified by the low-noise amplifier to output P-band and S-band transmitted electrical signals. The antenna array, comprising multiple antenna elements, is connected one-to-one with each output terminal of the photoelectric conversion array, and is used to simultaneously transmit the P-band and S-band transmitted electrical signals into free space, forming a dual-band multi-beam array with a reconfigurable wavefront.

2. The P / S cross-band wavefront reconfigurable multi-beam transmitting array system according to claim 1, characterized in that, The optical frequency comb generator is an intensity-phase cascaded electro-optic modulator. By adjusting the phase relationship of the driving signal entering the modulator, multiple optical frequency comb teeth with controllable flatness are generated.

3. The P / S cross-band wavefront reconfigurable multi-beam transmitting array system according to claim 1, characterized in that, The first Mach-Zehnder modulator, the second Mach-Zehnder modulator, and the third Mach-Zehnder modulator each control their bias voltage through loop feedback to operate at the minimum bias point, thereby achieving carrier suppression.

4. The P / S cross-band wavefront reconfigurable multi-beam transmitting array system according to claim 1, characterized in that, The first programmable photonic filter and the second programmable photonic filter are multi-channel optical waveguide type programmable filters, used to independently apply amplitude weights and phase weights to the optical signals of each channel in order to realize the shape reconstruction of the transmitted wavefront.

5. The P / S cross-band wavefront reconfigurable multi-beam transmitting array system according to claim 1, characterized in that, The first periodic narrowband filter and the second periodic narrowband filter are Fabry-Perot resonators or microring resonators, whose free spectral range is equal to that of the optical frequency comb, and whose passband width satisfies a positive first-order sideband and negative first-order sideband suppression ratio greater than 20dB, and whose transmission peak is aligned with the positive first-order sideband.

6. The P / S cross-band wavefront reconfigurable multi-beam transmitting array system according to claim 1, characterized in that, The dewavelength division multiplexer is an arrayed waveguide grating or a cascaded microring resonator, the number of its channels is equal to the number of the optical frequency comb teeth, and its transmission peak spacing is equal to the free spectral range of the optical frequency comb.

7. The P / S cross-band wavefront reconfigurable multi-beam transmitting array system according to claim 1, characterized in that, The passband of the dual-band filter simultaneously covers the center frequencies of the P-band and S-band, with a 3dB passband width greater than 50MHz and out-of-band rejection greater than 20dB.

8. The P / S cross-band wavefront reconfigurable multi-beam transmitting array system according to claim 1, characterized in that, The element spacing of the antenna array satisfies the following conditions to avoid grating lobes during P-band and S-band signal transmission: ； in, This indicates the element spacing of the antenna array; This represents the smaller of the wavelengths corresponding to the center frequencies of the P-band and S-band.

9. The P / S cross-band wavefront reconfigurable multi-beam transmitting array system according to claim 1, characterized in that, The amplitude and phase weights applied by the first and second programmable photonic filters are calculated using the subspace projection method to form a beam null in a specified direction; the formula for calculating the weight vector using the subspace projection method is as follows: ； in, This represents the weight vector of the subspace projection method; The orthogonal complement projection matrix of the interference subspace is represented. The steering vector that represents the direction of the desired signal; This indicates the conjugate transpose.

10. The P / S cross-band wavefront reconfigurable multi-beam transmitting array system according to claim 1, characterized in that, The frequency of the first local oscillator signal is the sum of the intermediate frequency signal frequency and the center frequency of the P-band, where the center frequency of the P-band is 0.98 GHz; the frequency of the second local oscillator signal is the sum of the intermediate frequency signal frequency and the center frequency of the S-band, where the center frequency of the S-band is 3.7 GHz; and the free spectral range of the optical frequency comb is 25 GHz.

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