Harmonic generation and beam control method and system based on amplitude and phase regulated metasurface array

Abstract

The application discloses a kind of based on amplitude-phase control metasurface array harmonic generation and beam control method and system.Method is: using the multi-channel radio frequency chip of digital control constructs amplitude-phase control metasurface array;Based on Fourier series and far-field superposition model, the time-varying amplitude-phase sequence of harmonic and the phase gradient of beam pointing are calculated;Through FPGA, sequence is converted into control signal, and each channel is modulated in real time;After array receives point frequency signal, by periodic amplitude-phase modulation and spatial phase gradient processing, target harmonic beam with preset characteristics is radiated to specified direction.The system includes four modules of amplitude-phase control metasurface array construction, harmonic and beam control model construction, digital control signal generation loading and target harmonic generation radiation, for realizing the harmonic generation and beam control method.The application realizes the accurate generation of arbitrary order harmonic and beam flexible deflection, improves system integration, control precision and real-time, and application field is wide.

Description

Technical Field

[0001] This invention relates to the field of time-controlled metasurface technology, specifically to a harmonic generation and beam control method and system based on amplitude-phase modulated metasurface arrays. Background Technology

[0002] In the field of metasurface radio frequency technology, metasurfaces, with their subwavelength thickness and flexible controllability of electromagnetic wave parameters, have become a research hotspot in the field of electromagnetic control. However, existing metasurface technologies generally have significant drawbacks: on the one hand, most metasurfaces adopt a single-dimensional control design or rely on the inherent electromagnetic response of the unit structure to achieve amplitude / phase control. This not only limits the degree of freedom of control, making it difficult to achieve coordinated and precise control of amplitude and phase, but also results in low control accuracy, failing to meet the high-precision control requirements of electromagnetic wave parameters in complex scenarios. See reference 1 (Emara MK, Kundu D, Macdonell K, et al. Reconfigurable metasurface reflectors using split-ring resonators with co-designed biasing for magnitude / phase control[J]. IEEE Transactions on Antennas and Propagation, 2024.) and reference 2 (Liang JC, Gao WH, Dai JY, et al. Adual-band 3-bit reconfigurable intelligent surface with independent control of phases[J]. ITU Journal on Future and Evolving Technologies, 2023.) 4(1):60-69.); On the other hand, traditional metasurfaces and radio frequency control devices have low integration, and often use discrete device combinations to achieve control functions, resulting in large system size, high power consumption, large control delay, and poor consistency between channels. See reference 3 (Saifullah Y, He Y, Boag A, et al. Recent progress in reconfigurable and intelligent metasurfaces: A comprehensive review of tuning mechanisms, hardware designs, and applications[J]. Advanced Science, 2022, 9(33):2203747.). In contrast, integrated amplitude and phase control chips have advantages such as multi-channel independent control, high-precision parameter control, and miniaturized integration. Combining them with metasurface arrays can effectively overcome the control bottleneck of traditional metasurfaces, but the relevant integration technology has not yet been maturely applied to the field of harmonic generation.

[0003] Harmonic modulation technology is a core supporting technology in fields such as wireless communication, radar detection, and electromagnetic compatibility testing, and its performance directly affects the overall system efficiency. Current metasurface-based harmonic generation technology still suffers from several key drawbacks: First, the controllability of harmonic orders is poor, relying mainly on the nonlinear effects of metasurface units to passively generate fixed-order harmonics, making it impossible to flexibly generate harmonics of arbitrary orders according to actual needs (see reference 4, Sun K, Wang K, Wang W, et al. High-Qphotonic flat-band resonances for enhancing third-harmonic generation in all-dielectric metasurfaces[J]. Newton, 2025, 1(4).); Second, the harmonic beam pointing is fixed, making it difficult to achieve precise deflection and flexible control of the harmonic beam, which limits its application in dynamic communication, precision detection, and other scenarios (see reference 5, Wu L, Wang ZX, Qi ZJ, et al. Amplifying Amplitude‐Phase Programmable Metasurface for Flexible Manipulation of Harmonic Beams[J]. Advanced Functional Materials, e21746.); Third, the amplitude and phase consistency of the harmonic signal are poor, resulting in insufficient stability of the generated harmonic signal parameters, which cannot meet the requirements of high-precision signal processing.

[0004] Therefore, in response to the shortcomings of existing metasurface technology, such as low modulation accuracy, difficulty in coordinated amplitude and phase modulation, poor controllability of harmonic generation order, and fixed beam pointing, developing a highly integrated and high-precision technical solution based on the combination of an integrated amplitude and phase modulation chip and a metasurface array, which can realize arbitrary harmonic generation and flexible beam control, has become a core technical problem that urgently needs to be solved in the field of metasurface radio frequency technology. It is of great significance to promote the application of metasurface technology in harmonic modulation and related fields. Summary of the Invention

[0005] The purpose of this invention is to provide a harmonic generation and beam control method and system based on amplitude and phase modulated metasurface arrays. By integrating amplitude and phase chips, the method achieves coordinated real-time control of amplitude and phase. Combined with the precise design of the harmonic control model, it realizes the accurate generation of harmonics of arbitrary order and flexible beam control. It also has the advantages of high system integration, high control accuracy, and strong stability.

[0006] The technical solution for achieving the objective of this invention is: a method for harmonic generation and beam control based on amplitude-phase modulated metasurface arrays, comprising the following steps:

[0007] Step 1: Construct an amplitude-phase modulated metasurface array based on an amplitude-phase multifunctional RF chip: An amplitude-phase modulated module is constructed using an externally digitally controlled one-to-many amplitude-phase multifunctional RF chip as the core modulating device. The amplitude-phase modulated module is connected to the metasurface receiving array and the metasurface transmitting array respectively to form an amplitude-phase modulated metasurface array.

[0008] Step 2: Constructing a harmonic and beam control model: Based on the Fourier series expansion principle, for the frequency, amplitude, and phase requirements of arbitrary order harmonics of the target, combined with the received point frequency signal carrier frequency, the periodically time-varying amplitude modulation sequence and phase modulation sequence are derived, and matched to the amplitude and phase control range that the amplitude and phase modulation module can achieve; based on the array far-field superposition formula, the scattering field of the column control array is derived, and the phase gradient of each order harmonic is introduced into the column control channel to control the pointing deflection of the corresponding harmonic beam;

[0009] Step 3: Generate and load digital control signals: Convert the periodically time-varying amplitude modulation sequence and phase modulation sequence into control codes for the amplitude-phase multi-functional RF chip. The FPGA generates control signals that meet the chip timing constraints to achieve independent real-time modulation of the amplitude and phase of each channel in the amplitude-phase modulation module.

[0010] Step 4: Generating and radiating target harmonics: A transmitting antenna radiates a point-frequency electromagnetic wave, which is captured by the metasurface receiving array. The resulting radio frequency signal is fed into the amplitude and phase modulation module. Each channel in the amplitude and phase modulation module periodically modulates the input radio frequency signal according to the corresponding control signal. The modulated signal drives the metasurface transmitting array to radiate the generated target harmonics with preset frequency, amplitude, and phase in the form of a beam by introducing a preset phase gradient between each channel, and guides them to a specified spatial direction.

[0011] Furthermore, the amplitude-phase multifunctional RF chip described in step 1 has a common COM RF input port and at least four independent transmit channels; each transmit channel integrates an amplitude attenuator and a phase shifter that can be independently digitally controlled.

[0012] The amplitude and phase multi-functional radio frequency chip integrates a power divider, channel radio frequency switches, and digital wave control circuit, which can independently control the amplitude, phase, and on / off state of each channel through external digital signals.

[0013] Furthermore, the amplitude-phase multi-functional RF chip integrates a one-to-four power divider, which decomposes the RF signal received by the COM RF input port into four identical RF signals, forming four transmission channels TX1~TX4. Each transmission channel is equipped with a channel RF switch to control the channel's activation.

[0014] The amplitude attenuator of each transmission channel is 6-bit digitally controlled with a step size of 0.5dB and a maximum attenuation amplitude of 31.5dB.

[0015] The phase shifter of each transmission channel is 6-bit digitally controlled with a step size of 5.625° and a phase shift range covering 0° to 360°.

[0016] When the chip is in the transmit state, the additional phase shift introduced by the amplitude attenuator operation does not exceed ±8°, and the additional amplitude change introduced by the phase shifter operation does not exceed ±2dB.

[0017] The digital wave control circuit has clock, data, chip select, and latch digital interfaces, and is configured by the FPGA to implement control functions.

[0018] Further, in step 1, the amplitude-phase multifunctional RF chip is soldered onto a PCB board, which has four layers in total, wherein:

[0019] The first layer is a signal layer, which is provided with a microstrip line structure connecting the amplitude and phase multifunctional radio frequency chip, the metasurface receiving array feed port and the metasurface transmitting array feed port, as well as digital signal traces and power lines for chip control. The microstrip line structure forms the first microstrip line feed network.

[0020] The second layer is the first dielectric layer, serving as the dielectric substrate for the microstrip line structure in the first layer;

[0021] The third layer is a metal grounding layer, which serves as the ground plane for the microstrip line structure in the first layer.

[0022] The fourth layer is a structural reinforcement layer. The mechanical strength of the substrate material is higher than that of the first dielectric layer, which is used to improve the physical strength of the overall printed circuit board.

[0023] Among them, the microstrip lines connecting different transmission channels of the same phase multi-functional RF chip are of equal length, and the microstrip lines transmitting RF signals are chamfered at the bends.

[0024] The output of the metasurface receiving array is connected to the RF input port of the amplitude-phase multifunctional RF chip through the first microstrip line feed network on the PCB board; each RF output port of the amplitude-phase multifunctional RF chip is connected to the input of the metasurface transmitting array through the first microstrip line feed network.

[0025] Furthermore, four amplitude and phase multi-functional RF chips are soldered to the first layer of the PCB board via chip pads;

[0026] The microstrip line width for transmitting radio frequency signals in the first microstrip line feed network is 0.4 mm;

[0027] The first dielectric layer in the PCB board is made of Rogers RO4350B with a thickness of 0.168mm.

[0028] The thickness of the metal ground layer in the PCB board is 0.035 mm;

[0029] The substrate material of the structural reinforcement layer in the PCB board is F4B, with a dielectric constant of 2.65, a dielectric loss tangent of 0.0027, and a thickness of 0.83 mm.

[0030] Furthermore, both the metasurface receiving array and the metasurface transmitting array in step 1 are multi-layer structures, and the basic array element includes, from top to bottom: a patch antenna radiating layer, at least one antenna dielectric substrate, a metal ground layer, a feed network dielectric substrate, and a microstrip line feed network layer.

[0031] The patch antenna is connected to the microstrip line feed network layer through an isolation hole on the metal ground layer via a vertical interconnect structure; the microstrip line feed network layer integrates a power divider network with multiple outputs.

[0032] A second microstrip line feed network is deployed in the microstrip line feed network layer of the metasurface receiving array. The second microstrip line feed network is used to combine the signals received by multiple array elements into one output to the amplitude-phase multifunctional radio frequency chip.

[0033] The microstrip line feed network layer in the metasurface emission array is equipped with a third microstrip line feed network, which is used to distribute one input signal from the amplitude-phase multifunctional radio frequency chip to multiple array elements for radiation.

[0034] Furthermore, the specific structures of the metasurface receiving array and the metasurface transmitting array are as follows:

[0035] (1) The metasurface receiving array operates in the Ku band and is composed of 16×16 basic array elements. The side length of each basic array element is 8mm, and it consists of six layers from top to bottom, wherein:

[0036] The first layer is a patch antenna radiating layer, which has rectangular receiving metal patches arranged symmetrically in the center. The receiving metal patches are square structures with a diameter of 4.9mm × 5.8mm.

[0037] The second layer is the first antenna dielectric substrate, which uses F4B material with a dielectric constant of 2.65, a dielectric loss tangent of 0.0027, and a thickness of 1.1 mm.

[0038] The third layer is the second antenna dielectric substrate, made of FR4 material with a dielectric constant of 4.3, a dielectric loss tangent of 0.025, and a thickness of 0.1 mm.

[0039] The fourth layer is a metal grounding layer with a thickness of 0.035mm, which forms the grounding plate of the microstrip line structure;

[0040] The fifth layer is the dielectric substrate of the power supply network, which uses Rogers RO4350B material with a dielectric constant of 3.66, a dielectric loss tangent of 0.0037, and a thickness of 0.168 mm, serving as the dielectric substrate for the microstrip line structure.

[0041] The sixth layer is the microstrip line feed network layer, which is a second microstrip line feed network formed by a microstrip line structure. The microstrip line is 0.4mm wide and 0.035mm thick, and it is equipped with 4 Wilkinson power dividers that split 1 to 64 channels and have isolation resistors.

[0042] The receiving metal patch of the first layer is connected to the second microstrip line feed network of the sixth layer through the first coaxial feed line. The radius of the first coaxial feed line is 0.3 mm, and an air hole with a radius of 0.52 mm is provided in the metal ground layer area through which the first coaxial feed line passes, so as to realize the isolation between the signal and the ground layer.

[0043] (2) The metasurface emission array also consists of six layers from top to bottom, wherein:

[0044] The first layer is the patch antenna radiating layer, with the rectangular transmitting metal patch having a square structure of 4.8mm × 6.6mm;

[0045] The structures of the second to fifth layers are the same as those of the second to fifth layers of the metasurface receiving array.

[0046] The sixth layer is the microstrip line feed network layer, which is equipped with a third microstrip line feed network formed by microstrip line structure, and has 16 sets of Wilkinson power dividers with isolation resistors that split from one to sixteen channels.

[0047] The first layer of transmitting metal patch is connected to the third microstrip line feed network of the sixth layer through the second coaxial feed line, and an air isolation hole with a radius of 0.56 mm is provided in the metal ground layer area through which the second coaxial feed line passes.

[0048] Furthermore, the construction of the harmonic and beam control model in step 2 is as follows:

[0049] (1) Time amplitude and phase modulation of harmonic modulation

[0050] Assume that the amplitude-phase modulated metasurface array receives a point frequency signal. , Represents the imaginary unit. The amplitude of the point frequency signal. The frequency of the point frequency signal. express time;

[0051] Amplitude-phase modulated metasurface arrays perform periodic amplitude and phase modulation on point frequency signals to obtain... Echo signal at time :

[0052] (1)

[0053] in, for The transport coefficient of the metasurface at time t is expressed as:

[0054] (2)

[0055] in, The magnitude of change over time. The phase that changes over time;

[0056] Due to the periodic modulation of the amplitude-phase modulated metasurface array, It is a periodically changing quantity, which can be expanded into a Fourier series as follows:

[0057] (3)

[0058] in, For the first The target amplitude value of the first harmonic. For the first The target phase value of the first harmonic; This is the fundamental frequency of the harmonic, which is also the frequency corresponding to the modulation period;

[0059] By setting the modulation period, the order of the target harmonic, and the relative amplitude and phase of each harmonic, the time-varying transmission coefficient is obtained, and this transmission coefficient is decomposed into amplitudes that vary with time. and phase that changes over time and will , Discretization yields the amplitude and phase control values ​​at each time point, thus forming the amplitude and phase control sequences for each channel;

[0060] (2) Beam control of target harmonics

[0061] Assume the metasurface emission array is located at the origin of the three-dimensional spherical coordinate system. There are a total of In this case, the radiated wave propagates in a spherical form and is considered a plane wave under far-field conditions;

[0062] Let the amplitude of the signal transmitted by each channel be... The initial phase is zero, and the carrier frequency is... Then the first Each element in time Radiated signals Represented as:

[0063] (4)

[0064] After adding the modulation obtained in step (1) to the signal of each channel, Represented as:

[0065] (5)

[0066] Assuming far-field point Located at the azimuth angle of the array Polar angle ,distance At this location, and satisfying the far-field condition, the amplitude attenuation factor is... Then the far field point Received the Each element in time radiation field Represented as:

[0067] (6)

[0068] in The cell period length of the array. The electromagnetic wave wavelength corresponding to the carrier frequency. The speed of light;

[0069] Far field point The total radiation field received by the array is Individual elements at the far field point The superposition of radiation fields, as expressed by equation (6) using the superposition theorem, is as follows:

[0070] (7)

[0071] Assuming control generation The same amplitude and in-phase harmonics of order 1 are sequentially controlled, and the deflection angle of the harmonics is... Then it is necessary to construct The phase is used to satisfy the phase delay caused by the direction deflection. ,for First harmonic, requires modulation to generate coefficients Represented as:

[0072] (8)

[0073] Phase term Spatial modulation is required to achieve this;

[0074] By controlling the phase difference of the harmonics modulated by each array channel in space, the phase difference is made to conform to the phase accumulation relationship determined by the target deflection angle, thereby realizing the beam deflection of the target order harmonics in a specified direction based on the harmonic amplitude and phase control.

[0075] Furthermore, in step 3, the specific process for generating and loading the digital control signal is as follows:

[0076] The FPGA development board is used to generate and transmit the control signals and control timing required for the amplitude-phase multi-functional RF chip.

[0077] The control timing is generated based on periodically time-varying amplitude modulation and phase modulation sequences, and converted into a binary timing control flow according to the control logic of the amplitude-phase multi-functional RF chip.

[0078] The binary timing control flow is imported into the FPGA through a hardware description language programming environment, and data storage and scheduling are performed using IP to generate and output clock signals, transmission signals containing amplitude and phase control data, chip select signals and latch signals that control the amplitude and phase multi-functional RF chip.

[0079] The FPGA has programmable logic units, memory and communication ports. The system clock frequency of the FPGA is greater than 100MHz, which can generate control signals that meet the timing requirements of the amplitude and phase multi-functional radio frequency chip, and realize independent real-time modulation of the amplitude and phase of each channel in the amplitude and phase modulation module.

[0080] A harmonic generation and beam control system based on amplitude-phase modulated metasurface arrays is disclosed. This system implements the aforementioned harmonic generation and beam control method based on amplitude-phase modulated metasurface arrays. The system includes an amplitude-phase modulated metasurface array construction module, a harmonic and beam control model construction module, a digital control signal generation and loading module, and a target harmonic generation and radiation module. The functions of each module are as follows:

[0081] Amplitude-phase modulated metasurface array construction module: An amplitude-phase modulated module is constructed using an externally digitally controlled multi-channel amplitude-phase multifunctional radio frequency chip as the core modulating device. The amplitude-phase modulated module is connected to the metasurface receiving array and the metasurface transmitting array respectively to form an amplitude-phase modulated metasurface array.

[0082] Harmonic and beam control model construction module: Based on the Fourier series expansion principle, for the frequency, amplitude and phase requirements of arbitrary order harmonics of the target, combined with the received point frequency signal carrier frequency, the periodic time-varying amplitude modulation sequence and phase modulation sequence are derived, and matched to the amplitude and phase control range that the amplitude and phase modulation module can achieve; based on the array far-field superposition formula, the scattering field of the column control array is derived, and the phase gradient of each order harmonic is introduced into the column control channel to control the pointing deflection of the corresponding harmonic beam;

[0083] Digital control signal generation and loading module: It converts the periodically time-varying amplitude modulation sequence and phase modulation sequence into the control code of the amplitude and phase multi-functional RF chip. The FPGA generates control signals that meet the chip timing constraints, so as to realize independent real-time modulation of the amplitude and phase of each channel in the amplitude and phase modulation module.

[0084] Target harmonic generation and radiation module: A transmitting antenna radiates a point-frequency electromagnetic wave, which is captured by the metasurface receiving array. The resulting radio frequency signal is fed into the amplitude and phase modulation module. Each channel in the amplitude and phase modulation module periodically modulates the amplitude and phase of the input radio frequency signal according to the corresponding control signal. The modulated signal drives the metasurface transmitting array to radiate the generated target harmonics with preset frequency, amplitude, and phase in the form of a beam by introducing a preset phase gradient between each channel, and guides them to a specified spatial direction.

[0085] Compared with the prior art, the significant advantages of this invention are:

[0086] (1) The present invention uses a one-to-four-channel amplitude and phase multifunctional radio frequency chip as the core control device, which integrates amplification, phase shifting, digital control attenuation and other functions. Each channel achieves 6-bit high-precision amplitude and phase control, which greatly improves the control accuracy of amplitude and phase. At the same time, the integration of the chip and the metasurface array is improved.

[0087] (2) Based on the Fourier series expansion principle, a harmonic control model is constructed. The periodic time-varying amplitude and phase control sequence can be flexibly derived according to the target requirements, realizing the accurate generation of harmonics of any order, breaking through the limitation of fixed harmonic order of traditional nonlinear devices; combined with the array far-field superposition formula, the phase gradient is introduced to realize the pointing deflection of each order of harmonic beam, improving the flexibility of beam control.

[0088] (3) FPGA is used to generate clock and digital control signals to realize real-time independent control of the amplitude, phase and switch of each channel, which ensures the real-time and synchronization of the regulation and solves the problems of large delay and poor consistency between channels in the traditional control method.

[0089] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0090] Figure 1 This is a schematic diagram of the amplitude and phase multifunctional radio frequency chip in this invention.

[0091] Figure 2 This is a schematic diagram of the amplitude and phase control module in this invention.

[0092] Figure 3a This is a top view of the metasurface receiving array designed in this invention.

[0093] Figure 3b This is a bottom view of the metasurface receiving array designed in this invention.

[0094] Figure 3c This is a side view of the metasurface receiving array unit and transmitting array unit designed in this invention.

[0095] Figure 4a This is a single-column top view of the metasurface emission array designed in this invention.

[0096] Figure 4b This is a single-column bottom view of the metasurface emission array designed in this invention.

[0097] Figure 5 denoted as the reflection coefficient of the metasurface receiving array port in this invention.

[0098] Figure 6 is the reflection coefficient of the metasurface emission array port in this invention.

[0099] Figure 7 This is a framework diagram of the harmonic and beam control model based on the amplitude-phase modulated metasurface array constructed in this invention.

[0100] Figure 8a This is the amplitude timing diagram for generating equal-amplitude and in-phase 1st to 2nd harmonics in this invention.

[0101] Figure 8b This is the phase timing diagram for generating equal-amplitude and in-phase first to second-order harmonics in this invention.

[0102] Figure 8c This is a harmonic amplitude diagram for generating equal-amplitude and in-phase first to second-order harmonics in this invention.

[0103] Figure 8d This is a harmonic phase diagram for generating equal-amplitude and in-phase first to second-order harmonics in this invention.

[0104] Figure 9a This is the amplitude timing diagram for generating 1st to 4th order harmonics with equal amplitude and phase difference in this invention.

[0105] Figure 9b This is the phase timing diagram for generating 1st to 4th order harmonics with equal amplitude and equal phase difference in this invention.

[0106] Figure 9c This is a harmonic amplitude diagram for generating 1st to 4th order harmonics with equal amplitude and phase difference in this invention.

[0107] Figure 9d This is a harmonic phase diagram for generating 1st to 4th order harmonics with equal amplitude and equal phase difference in this invention.

[0108] Figure 10a The phase diagrams of arrays 1 to 16, which generate equal-amplitude and in-phase 1st to 2nd harmonics and whose beams are deflected by 10 degrees and -20 degrees respectively, are used in this invention.

[0109] Figure 10b The beam pattern of the -2 to +2nd order harmonics of the array that generates equal amplitude and in phase 1st to 2nd order harmonics with beam deflection of 10 degrees and -20 degrees respectively is shown in the present invention.

[0110] Figure 11a The phase diagrams of arrays 1 to 16, which generate equal-amplitude and in-phase 1st to 4th harmonics and whose beams are deflected by 10 degrees, 20 degrees, 30 degrees, and 40 degrees respectively, are used in this invention.

[0111] Figure 11b The beam pattern of the array of -4 to +4 harmonics, which generates equal amplitude and in phase 1st to 4th harmonics in this invention, with beams deflected by 10 degrees, 20 degrees, 30 degrees, and 40 degrees respectively. Detailed Implementation

[0112] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. It is readily understood that, based on the technical solutions of the present invention, those skilled in the art can conceive of various embodiments of the present invention without altering its essential spirit. Therefore, the following specific embodiments and accompanying drawings are merely illustrative examples of the technical solutions of the present invention and should not be considered as the entirety of the present invention or as limitations or restrictions on the technical solutions of the present invention.

[0113] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0114] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0115] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0116] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0117] This invention provides a method and system for harmonic generation and beam control based on amplitude-phase modulated metasurface arrays. By integrating amplitude and phase chips, it achieves coordinated real-time control of amplitude and phase. Combined with the precise design of the harmonic control model, it can realize the accurate generation of harmonics of any order and the flexible and controllable deflection of the beam. It also has the advantages of high system integration, high control accuracy, and strong stability, thereby improving the integration and real-time performance of the control system.

[0118] This invention provides a method for harmonic generation and beam control based on amplitude-phase modulated metasurface arrays, the steps of which are as follows:

[0119] Step 1: Construct an amplitude-phase modulated metasurface array based on an amplitude-phase multifunctional RF chip: An amplitude-phase modulated module is constructed using an externally digitally controlled one-to-many amplitude-phase multifunctional RF chip as the core modulating device. The amplitude-phase modulated module is connected to the metasurface receiving array and the metasurface transmitting array respectively to form an amplitude-phase modulated metasurface array.

[0120] Step 2: Constructing a harmonic and beam control model: Based on the Fourier series expansion principle, for the frequency, amplitude, and phase requirements of arbitrary order harmonics of the target, combined with the received point frequency signal carrier frequency, the periodically time-varying amplitude modulation sequence and phase modulation sequence are derived, and matched to the amplitude and phase control range that the amplitude and phase modulation module can achieve; based on the array far-field superposition formula, the scattering field of the column control array is derived, and the phase gradient of each order harmonic is introduced into the column control channel to control the pointing deflection of the corresponding harmonic beam;

[0121] Step 3: Generate and load digital control signals: Convert the periodically time-varying amplitude modulation sequence and phase modulation sequence into control codes for the amplitude-phase multi-functional RF chip. The FPGA generates control signals that meet the chip timing constraints to achieve independent real-time modulation of the amplitude and phase of each channel in the amplitude-phase modulation module.

[0122] Step 4: Generating and radiating target harmonics: A transmitting antenna radiates a point-frequency electromagnetic wave, which is captured by the metasurface receiving array. The resulting radio frequency signal is fed into the amplitude and phase modulation module. Each channel in the amplitude and phase modulation module periodically modulates the input radio frequency signal according to the corresponding control signal. The modulated signal drives the metasurface transmitting array to radiate the generated target harmonics with preset frequency, amplitude, and phase in the form of a beam by introducing a preset phase gradient between each channel, and guides them to a specified spatial direction.

[0123] As a specific example, step 4 is followed by a verification step, which is as follows: the radiated signal is acquired by the receiving antenna placed in the specified direction, and after Fourier transform and spectrum analysis, the harmonic signal that is consistent with the preset value is extracted, thereby verifying the harmonic generation and beam steering functions.

[0124] As a specific example, the amplitude-phase multi-functional RF chip described in step 1 has a common COM RF input port and at least four independent transmit channels; each transmit channel integrates an amplitude attenuator and a phase shifter that can be independently digitally controlled.

[0125] The amplitude and phase multi-functional radio frequency chip integrates a power divider, channel radio frequency switches, and digital wave control circuit, which can independently control the amplitude, phase, and on / off state of each channel through external digital signals.

[0126] As a specific example, the amplitude-phase multi-function RF chip integrates a one-to-four power divider, which decomposes the RF signal received by the COM RF input port into four identical RF signals, forming four transmission channels TX1~TX4. Each transmission channel is equipped with a channel RF switch to control the channel's activation.

[0127] The amplitude attenuator of each transmission channel is 6-bit digitally controlled with a step size of 0.5dB and a maximum attenuation amplitude of 31.5dB.

[0128] The phase shifter of each transmission channel is 6-bit digitally controlled with a step size of 5.625° and a phase shift range covering 0° to 360°.

[0129] When the chip is in the transmit state, the additional phase shift introduced by the amplitude attenuator operation does not exceed ±8°, and the additional amplitude change introduced by the phase shifter operation does not exceed ±2dB.

[0130] The digital wave control circuit has clock, data, chip select, and latch digital interfaces, and is configured by the FPGA to implement control functions.

[0131] As a specific example, the amplitude and phase multifunction RF chip used is the GNFD140180-2 multifunction chip from Nanjing Guobo Electronics Co., Ltd., and its block diagram is shown below. Figure 1This is a four-channel multi-functional chip (MMIC) integrating amplification, phase shifting, and digitally controlled attenuation. It integrates wave control circuitry and ID codes, and features address and data readback capabilities. It is manufactured using germanium-silicon BiCMOS technology. The chip is grounded via a through-hole on the back metal. All chips undergo 100% RF testing. The chip operates on a +5V / +5V power supply and can be used in various phased array transceiver systems. Key technical specifications are as follows: Frequency range: 14~16GHz; Input / output VSWR: 1.6; Transmit gain: 8dB; Transmit P-1 output: 10dBm; 6-bit phase shifter step: 5.625°; Phase shift accuracy RMS: 3°; 6-bit attenuator step: 0.5dB; Attenuation accuracy RMS: 0.6dB.

[0132] As a specific example, such as Figure 2 As shown, the amplitude-phase multifunctional RF chip is soldered onto a PCB board, which has four layers:

[0133] The first layer is a signal layer, which is provided with a microstrip line structure (with a 50Ω port) connecting the amplitude and phase multifunctional RF chip, the metasurface receiver array feed port and the metasurface transmitter array feed port, as well as digital signal traces and power lines for chip control. The microstrip line structure forms the first microstrip line feed network.

[0134] The second layer is the first dielectric layer, serving as the dielectric substrate for the microstrip line structure in the first layer;

[0135] The third layer is a metal grounding layer, which serves as the ground plane for the microstrip line structure in the first layer.

[0136] The fourth layer is a structural reinforcement layer. The mechanical strength of the substrate material is higher than that of the first dielectric layer, which is used to improve the physical strength of the overall printed circuit board.

[0137] Among them, the microstrip lines connecting different transmission channels of the same phase multi-functional RF chip are of equal length, and the microstrip lines transmitting RF signals are chamfered at the bends to reduce signal reflection.

[0138] The output of the metasurface receiving array is connected to the RF input port of the amplitude-phase multifunctional RF chip through the first microstrip line feed network on the PCB board; each RF output port of the amplitude-phase multifunctional RF chip is connected to the input of the metasurface transmitting array through the first microstrip line feed network.

[0139] As a specific example, four amplitude and phase multifunction RF chips are soldered to the first layer of the PCB board via chip pads;

[0140] The microstrip line width for transmitting radio frequency signals in the first microstrip line feed network is 0.4 mm;

[0141] The first dielectric layer in the PCB board is made of Rogers RO4350B with a thickness of 0.168mm.

[0142] The thickness of the metal ground layer in the PCB board is 0.035 mm;

[0143] The substrate material of the structural reinforcement layer in the PCB board is F4B, with a dielectric constant of 2.65, a dielectric loss tangent of 0.0027, and a thickness of 0.83mm. It is used to supplement the PCB thickness and increase the structural strength of the PCB.

[0144] As a specific example, the amplitude and phase modulation module integrates four of the aforementioned amplitude and phase multifunctional RF chips, with a total of 4 RF inputs and 16 RF outputs. It can decompose the four input RF signals into 16 equal-amplitude and in-phase outputs. At the same time, under the control of the FPGA, it can select the switching of channels and simultaneously modulate the amplitude and phase of the 16 outputs.

[0145] As a specific example, both the metasurface receiving array and the metasurface transmitting array in step 1 are multi-layer structures. The basic array element includes, from top to bottom: a patch antenna radiating layer, at least one antenna dielectric substrate, a metal ground layer, a feed network dielectric substrate, and a microstrip line feed network layer.

[0146] The patch antenna is connected to the microstrip line feed network layer through an isolation hole on the metal ground layer via a vertical interconnect structure; the microstrip line feed network layer integrates a power divider network with multiple outputs.

[0147] A second microstrip line feed network is deployed in the microstrip line feed network layer of the metasurface receiving array. The second microstrip line feed network is used to combine the signals received by multiple array elements into one output to the amplitude-phase multifunctional radio frequency chip.

[0148] The microstrip line feed network layer in the metasurface emission array is equipped with a third microstrip line feed network, which is used to distribute one input signal from the amplitude-phase multifunctional radio frequency chip to multiple array elements for radiation.

[0149] As a specific example, the structures of the metasurface receiving array and the metasurface transmitting array in step 1 are as follows:

[0150] (1) The metasurface receiving array operates in the Ku band, combined with Figure 3a , Figure 3b , Figure 3c The array model is designed as a multi-layered structure, consisting of 16×16 basic array elements arranged in a grid. Each basic array element has a side length of 8mm, and the array comprises six layers from top to bottom.

[0151] The first layer is a patch antenna radiating layer, which has rectangular receiving metal patches arranged symmetrically in the center. The receiving metal patches are square structures with a diameter of 4.9mm × 5.8mm.

[0152] The second layer is the first antenna dielectric substrate, which uses F4B material with a dielectric constant of 2.65, a dielectric loss tangent of 0.0027, and a thickness of 1.1 mm.

[0153] The third layer is the second antenna dielectric substrate, made of FR4 material with a dielectric constant of 4.3, a dielectric loss tangent of 0.025, and a thickness of 0.1 mm.

[0154] The fourth layer is a metal grounding layer with a thickness of 0.035mm, which forms the grounding plate of the microstrip line structure;

[0155] The fifth layer is the dielectric substrate of the power supply network, which uses Rogers RO4350B material with a dielectric constant of 3.66, a dielectric loss tangent of 0.0037, and a thickness of 0.168 mm, serving as the dielectric substrate for the microstrip line structure.

[0156] The sixth layer is the microstrip line feed network layer, which is a second microstrip line feed network formed by a microstrip line structure. The microstrip line is 0.4mm wide and 0.035mm thick, and it is equipped with 4 Wilkinson power dividers that split 1 to 64 channels and have isolation resistors.

[0157] The receiving metal patch of the first layer is connected to the second microstrip line feed network of the sixth layer through the first coaxial feed line. The radius of the first coaxial feed line is 0.3 mm, and an air hole with a radius of 0.52 mm is provided in the metal ground layer area through which the first coaxial feed line passes, so as to realize the isolation between the signal and the ground layer.

[0158] (2) The metasurface emission array also consists of six layers from top to bottom, combined with Figure 4a , Figure 4b ,in:

[0159] The first layer is the patch antenna radiating layer, with the rectangular transmitting metal patch having a square structure of 4.8mm × 6.6mm;

[0160] The structures of the second to fifth layers are the same as those of the second to fifth layers of the metasurface receiving array.

[0161] The sixth layer is the microstrip line feed network layer, which is equipped with a third microstrip line feed network formed by microstrip line structure, and has 16 sets of Wilkinson power dividers with isolation resistors that split from one to sixteen channels.

[0162] The first layer of transmitting metal patch is connected to the third microstrip line feed network of the sixth layer through the second coaxial feed line, and an air isolation hole with a radius of 0.56 mm is provided in the metal ground layer area through which the second coaxial feed line passes.

[0163] As a specific example, the port performance metrics of the metasurface receiving array and the metasurface transmitting array in step 1 are combined. Figure 5 , Figure 6 To clarify, the frequency band with a reflection coefficient below -10dB at the metasurface receiving array port is 14.40~17.10GHz, and the frequency band with a reflection coefficient below -10dB at the metasurface transmitting array port is 15.35~17.04GHz. These two arrays have a certain common frequency band and can be matched with each other.

[0164] As a specific example, step 2, which involves constructing a harmonic and beam control model, is explained in two parts, as illustrated in the schematic diagram below. Figure 7 As shown, the details are as follows:

[0165] (1) Time amplitude and phase modulation of harmonic modulation

[0166] Assume that the amplitude-phase modulated metasurface array receives a point frequency signal. , Represents the imaginary unit. The amplitude of the point frequency signal. The frequency of the point frequency signal. express time;

[0167] Amplitude-phase modulated metasurface arrays perform periodic amplitude and phase modulation on point frequency signals to obtain... Echo signal at time :

[0168] (1)

[0169] in, for The transport coefficient of the metasurface at time t is expressed as:

[0170] (2)

[0171] in, The magnitude of change over time. The phase that changes over time;

[0172] Due to the periodic modulation of the amplitude-phase modulated metasurface array, It is a periodically changing quantity, which can be expanded into a Fourier series as follows:

[0173] (3)

[0174] in, For the first The target amplitude value of the first harmonic. For the first The target phase value of the first harmonic; This is the fundamental frequency of the harmonic, which is also the frequency corresponding to the modulation period;

[0175] By setting the modulation period, the order of the target harmonic, and the relative amplitude and phase of each harmonic, the time-varying transmission coefficient is obtained, and this transmission coefficient is decomposed into amplitudes that vary with time. and phase that changes over time and will , Discretization yields the amplitude and phase control values ​​at each time point, thus forming the amplitude and phase control sequences for each channel.

[0176] As a specific example, control the generation of the following two sets of examples:

[0177] The first group of equal-amplitude and in-phase 1st and 2nd harmonics, at this time equation (3) is written as ;

[0178] The second group consists of harmonics of the 1st to 4th orders with equal amplitude and a 90-degree phase difference. The phase difference is relative to the previous harmonic. In this case, formula (3) is written as... ;

[0179] Will and The time-varying amplitude and time-varying phase are separated, and one cycle is discretized into 100 points. The time-varying amplitude is normalized to the maximum value. Then, the amplitude and phase at each moment are mapped to the amplitude attenuation value and phase modulation value that the chip can achieve, and the amplitude attenuation value and phase modulation value with the smallest numerical difference are used instead. Figure 8a , Figure 8b , Figure 8c , Figure 8d The diagrams are, in order, the amplitude timing diagram, the phase timing diagram, the harmonic amplitude diagram, and the harmonic phase diagram for generating equal-amplitude and in-phase first and second-order harmonics. Figure 9a , Figure 9b , Figure 9c , Figure 9d The diagrams are, in order, the amplitude timing diagram, the phase timing diagram, the harmonic amplitude diagram, and the harmonic phase diagram for generating 1st to 4th order harmonics with equal amplitude and phase difference.

[0180] (2) Beam control of target harmonics

[0181] Assume the metasurface emission array is located at the origin of the three-dimensional spherical coordinate system. There are a total of In this case, the radiated wave propagates in a spherical form and is considered a plane wave under far-field conditions;

[0182] Assume the signal incident on the receiving array element is in simple harmonic form, the receiving array receives the signal perpendicular to the incident wave direction, and the signals of each channel after being combined and decomposed by the power divider remain in phase. Let the amplitude of the signal transmitted by each channel be... The initial phase is zero, and the carrier frequency is... Then the first Each element in time Radiated signals Represented as:

[0183] (4)

[0184] After adding the modulation obtained in step (1) to the signal of each channel, Represented as:

[0185] (5)

[0186] Assuming far-field point Located at the azimuth angle of the array Polar angle ,distance At this location, and satisfying the far-field condition, the amplitude attenuation factor is... Then the far field point Received the Each element in time radiation field Represented as:

[0187] (6)

[0188] in The cell period length of the array. The electromagnetic wave wavelength corresponding to the carrier frequency. The speed of light;

[0189] Far field point The total radiation field received by the array is Individual elements at the far field point The superposition of radiation fields, as expressed by equation (6) using the superposition theorem, is as follows:

[0190] (7)

[0191] Assuming control generation The same amplitude and in-phase harmonics of order 1 are sequentially controlled, and the deflection angle of the harmonics is... Then it is necessary to construct The phase is used to satisfy the phase delay caused by the direction deflection. ,for First harmonic, requires modulation to generate coefficients Represented as:

[0192] (8)

[0193] Phase term Spatial modulation is required to achieve this;

[0194] By controlling the phase difference of the harmonics modulated by each array channel in space, the phase difference is made to conform to the phase accumulation relationship determined by the target deflection angle, thereby realizing the beam deflection of the target order harmonics in a specified direction based on the harmonic amplitude and phase control.

[0195] As a specific example, control the generation of the following two sets of examples:

[0196] The first group consists of 1st and 2nd harmonics of equal amplitude and phase, with the two harmonics deflected at angles of 10 degrees and -20 degrees respectively. In this case, equation (3) is written as , No. The time-varying coefficients of each channel are ;

[0197] The second group consists of 1st to 4th harmonics of equal amplitude and phase. The fourth harmonics are deflected at angles of 10 degrees, 20 degrees, 30 degrees, and 40 degrees, respectively. In this case, formula (3) is written as ;No. The time-varying coefficients for each channel are:

[0198]

[0199] Similarly and The time-varying amplitude and phase are separated, and one period is discretized into 100 points. The time-varying amplitude is normalized to its maximum value. The amplitude and phase at each moment are mapped to the phase modulation value that the chip can achieve amplitude attenuation. The phase modulation value with the smallest numerical difference is used instead. Spatial modulation is added here. Each column of the transmit array is modulated according to the transmission coefficient of each column. The phase result of the Fourier transform of the transmission coefficient of each channel is as follows. Figure 10a , Figure 11a As shown, it reflects the phase gradient added to each channel by spatial modulation, and the radiation patterns of each harmonic are as follows. Figure 10b , Figure 11b As shown, the expected result is achieved.

[0200] As a specific example, the specific process for generating and loading digital control signals in step 3 is as follows:

[0201] The FPGA development board is used to generate and transmit the control signals and control timing required for the amplitude-phase multi-functional RF chip.

[0202] The control timing is generated based on periodically time-varying amplitude modulation and phase modulation sequences, and converted into a binary timing control flow according to the control logic of the amplitude-phase multi-functional RF chip.

[0203] The binary timing control flow is imported into the FPGA through a hardware description language programming environment, and data storage and scheduling are performed using IP to generate and output clock signals, transmission signals containing amplitude and phase control data, chip select signals and latch signals that control the amplitude and phase multi-functional RF chip.

[0204] The FPGA has programmable logic units, memory and communication ports. The system clock frequency of the FPGA is greater than 100MHz, which can generate control signals that meet the timing requirements of the amplitude and phase multi-functional radio frequency chip, and realize independent real-time modulation of the amplitude and phase of each channel in the amplitude and phase modulation module.

[0205] As a specific example, this invention uses the high-end FPGA development platform of the Black Gold ARTIX-7 series, model AX7103, which has free programmability, certain memory, logic units and transmission ports. The core board is equipped with an active differential crystal oscillator with a clock frequency of 200MHz, which is used for the FPGA's system main clock and for generating the DDR3 control clock, and can generate timing requirements that meet the RF chip.

[0206] The development board is used to generate the control signals required by the chip and transmit the control timing. The control timing is generated based on the formula in step 2 and matched to the control values ​​that the specific chip can achieve. According to the control logic of the selected chip, a binary timing control flow is generated. The FPGA program is written using Vivado, which requires importing the binary timing control flow and storing the data in the IP core. The program can control the chip's clock signal, data transmission (transmission of amplitude and phase control timing), chip select and latch signals, etc.

[0207] In one embodiment, the present invention also provides a harmonic generation and beam control system based on an amplitude-phase modulated metasurface array. This system is used to implement the aforementioned harmonic generation and beam control method based on an amplitude-phase modulated metasurface array. The system includes an amplitude-phase modulated metasurface array construction module, a harmonic and beam control model construction module, a digital control signal generation and loading module, and a target harmonic generation and radiation module. The functions of each module are as follows:

[0208] Amplitude-phase modulated metasurface array construction module: An amplitude-phase modulated module is constructed using an externally digitally controlled multi-channel amplitude-phase multifunctional radio frequency chip as the core modulating device. The amplitude-phase modulated module is connected to the metasurface receiving array and the metasurface transmitting array respectively to form an amplitude-phase modulated metasurface array.

[0209] Harmonic and beam control model construction module: Based on the Fourier series expansion principle, for the frequency, amplitude and phase requirements of arbitrary order harmonics of the target, combined with the received point frequency signal carrier frequency, the periodic time-varying amplitude modulation sequence and phase modulation sequence are derived, and matched to the amplitude and phase control range that the amplitude and phase modulation module can achieve; based on the array far-field superposition formula, the scattering field of the column control array is derived, and the phase gradient of each order harmonic is introduced into the column control channel to control the pointing deflection of the corresponding harmonic beam;

[0210] Digital control signal generation and loading module: It converts the periodically time-varying amplitude modulation sequence and phase modulation sequence into the control code of the amplitude and phase multi-functional RF chip. The FPGA generates control signals that meet the chip timing constraints, so as to realize independent real-time modulation of the amplitude and phase of each channel in the amplitude and phase modulation module.

[0211] Target harmonic generation and radiation module: A transmitting antenna radiates a point-frequency electromagnetic wave, which is captured by the metasurface receiving array. The resulting radio frequency signal is fed into the amplitude and phase modulation module. Each channel in the amplitude and phase modulation module periodically modulates the amplitude and phase of the input radio frequency signal according to the corresponding control signal. The modulated signal drives the metasurface transmitting array to radiate the generated target harmonics with preset frequency, amplitude, and phase in the form of a beam by introducing a preset phase gradient between each channel, and guides them to a specified spatial direction.

[0212] In one embodiment, the present invention also provides a mobile terminal, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the harmonic generation and beam control method based on amplitude-phase modulated metasurface array.

[0213] In one embodiment, the present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the harmonic generation and beam control method based on amplitude-phase modulated metasurface array.

[0214] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

[0215] It should be understood that, in order to simplify the present invention and help those skilled in the art understand its various aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes described in a single embodiment or with reference to a single figure. However, the present invention should not be construed as including all features in the exemplary embodiments as essential technical features of the present invention.

Claims

1. A method for harmonic generation and beam control based on amplitude-phase modulated metasurface arrays, characterized in that, Includes the following steps: Step 1: Construct an amplitude-phase modulated metasurface array based on an amplitude-phase multifunctional RF chip: An amplitude-phase modulated module is constructed using an externally digitally controlled one-to-many amplitude-phase multifunctional RF chip as the core modulating device. The amplitude-phase modulated module is connected to the metasurface receiving array and the metasurface transmitting array respectively to form an amplitude-phase modulated metasurface array. Step 2: Constructing a harmonic and beam control model: Based on the Fourier series expansion principle, for the frequency, amplitude, and phase requirements of arbitrary order harmonics of the target, combined with the received point frequency signal carrier frequency, the periodically time-varying amplitude modulation sequence and phase modulation sequence are derived, and matched to the amplitude and phase control range that the amplitude and phase modulation module can achieve; based on the array far-field superposition formula, the scattering field of the column control array is derived, and the phase gradient of each order harmonic is introduced into the column control channel to control the pointing deflection of the corresponding harmonic beam; Step 3: Generate and load digital control signals: Convert the periodically time-varying amplitude modulation sequence and phase modulation sequence into control codes for the amplitude-phase multi-functional RF chip. The FPGA generates control signals that meet the chip timing constraints to achieve independent real-time modulation of the amplitude and phase of each channel in the amplitude-phase modulation module. Step 4: Generate and radiate target harmonics: A transmitting antenna radiates a point-frequency electromagnetic wave, which is captured by the metasurface receiving array, and the resulting radio frequency signal is fed into the amplitude and phase modulation module. Each channel in the amplitude and phase modulation module performs periodic amplitude and phase modulation on the input radio frequency signal according to the corresponding control signal. The modulated signal drives the metasurface emission array, which radiates the generated target harmonics with preset frequency, amplitude and phase in the form of beams by introducing a preset phase gradient between each channel, and guides them to a specified spatial direction.

2. The harmonic generation and beam control method based on amplitude-phase modulated metasurface array according to claim 1, characterized in that, The amplitude-phase multi-functional RF chip described in step 1 has a common COM RF input port and at least four independent transmit channels; each transmit channel integrates an amplitude attenuator and a phase shifter that can be independently digitally controlled. The amplitude and phase multi-functional radio frequency chip integrates a power divider, channel radio frequency switches, and digital wave control circuit, which can independently control the amplitude, phase, and on / off state of each channel through external digital signals.

3. The harmonic generation and beam control method based on amplitude-phase modulated metasurface array according to claim 2, characterized in that, The aforementioned amplitude-phase multi-functional RF chip integrates a one-to-four power divider, which decomposes the RF signal received by the COM RF input port into four identical RF signals, forming four transmission channels TX1~TX4. Each transmission channel is equipped with a channel RF switch to control the channel's activation. The amplitude attenuator of each transmission channel is 6-bit digitally controlled with a step size of 0.5dB and a maximum attenuation amplitude of 31.5dB. The phase shifter of each transmission channel is 6-bit digitally controlled with a step size of 5.625° and a phase shift range covering 0° to 360°. When the chip is in the transmit state, the additional phase shift introduced by the amplitude attenuator operation does not exceed ±8°, and the additional amplitude change introduced by the phase shifter operation does not exceed ±2dB. The digital wave control circuit has clock, data, chip select, and latch digital interfaces, and is configured by the FPGA to implement control functions.

4. The harmonic generation and beam control method based on amplitude-phase modulated metasurface array according to claim 1, characterized in that, In step 1, the amplitude-phase multifunctional RF chip is soldered onto a PCB board, which has four layers: The first layer is a signal layer, which is provided with a microstrip line structure connecting the amplitude and phase multifunctional radio frequency chip, the metasurface receiving array feed port and the metasurface transmitting array feed port, as well as digital signal traces and power lines for chip control. The microstrip line structure forms the first microstrip line feed network. The second layer is the first dielectric layer, serving as the dielectric substrate for the microstrip line structure in the first layer; The third layer is a metal grounding layer, which serves as the ground plane for the microstrip line structure in the first layer. The fourth layer is a structural reinforcement layer. The mechanical strength of the substrate material is higher than that of the first dielectric layer, which is used to improve the physical strength of the overall printed circuit board. Among them, the microstrip lines connecting different transmission channels of the same phase multi-functional RF chip are of equal length, and the microstrip lines transmitting RF signals are chamfered at the bends. The output of the metasurface receiving array is connected to the RF input port of the amplitude-phase multifunctional RF chip through the first microstrip line feed network on the PCB board; each RF output port of the amplitude-phase multifunctional RF chip is connected to the input of the metasurface transmitting array through the first microstrip line feed network.

5. The harmonic generation and beam control method based on amplitude-phase modulated metasurface array according to claim 4, characterized in that, Four amplitude and phase multi-functional RF chips are soldered to the first layer of the PCB board via chip pads; The microstrip line width for transmitting radio frequency signals in the first microstrip line feed network is 0.4 mm; The first dielectric layer in the PCB board is made of Rogers RO4350B with a thickness of 0.168mm. The thickness of the metal ground layer in the PCB board is 0.035 mm; The substrate material of the structural reinforcement layer in the PCB board is F4B, with a dielectric constant of 2.65, a dielectric loss tangent of 0.0027, and a thickness of 0.83 mm.

6. The harmonic generation and beam control method based on amplitude-phase modulated metasurface array according to claim 1, characterized in that, Both the metasurface receiving array and the metasurface transmitting array in step 1 are multi-layer structures. The basic array element includes, from top to bottom: a patch antenna radiating layer, at least one antenna dielectric substrate, a metal ground layer, a feed network dielectric substrate, and a microstrip line feed network layer. The patch antenna is connected to the microstrip line feed network layer through an isolation hole on the metal ground layer via a vertical interconnect structure; the microstrip line feed network layer integrates a power divider network with multiple outputs. A second microstrip line feed network is deployed in the microstrip line feed network layer of the metasurface receiving array. The second microstrip line feed network is used to combine the signals received by multiple array elements into one output to the amplitude-phase multifunctional radio frequency chip. The microstrip line feed network layer in the metasurface emission array is equipped with a third microstrip line feed network, which is used to distribute one input signal from the amplitude-phase multifunctional radio frequency chip to multiple array elements for radiation.

7. The harmonic generation and beam control method based on amplitude-phase modulated metasurface arrays according to claim 6, characterized in that, The specific structures of the metasurface receiving array and the metasurface transmitting array are as follows: (1) The metasurface receiving array operates in the Ku band and is composed of 16×16 basic array elements. The side length of each basic array element is 8mm, and it consists of six layers from top to bottom, wherein: The first layer is a patch antenna radiating layer, which has rectangular receiving metal patches arranged symmetrically in the center. The receiving metal patches are square structures with a diameter of 4.9mm × 5.8mm. The second layer is the first antenna dielectric substrate, which uses F4B material with a dielectric constant of 2.65, a dielectric loss tangent of 0.0027, and a thickness of 1.1 mm. The third layer is the second antenna dielectric substrate, made of FR4 material with a dielectric constant of 4.3, a dielectric loss tangent of 0.025, and a thickness of 0.1 mm. The fourth layer is a metal grounding layer with a thickness of 0.035mm, which forms the grounding plate of the microstrip line structure; The fifth layer is the dielectric substrate of the power supply network, which uses Rogers RO4350B material with a dielectric constant of 3.66, a dielectric loss tangent of 0.0037, and a thickness of 0.168 mm, serving as the dielectric substrate for the microstrip line structure. The sixth layer is the microstrip line feed network layer, which is a second microstrip line feed network formed by a microstrip line structure. The microstrip line is 0.4mm wide and 0.035mm thick, and it is equipped with 4 Wilkinson power dividers that split 1 to 64 channels and have isolation resistors. The receiving metal patch of the first layer is connected to the second microstrip line feed network of the sixth layer through the first coaxial feed line. The radius of the first coaxial feed line is 0.3 mm, and an air hole with a radius of 0.52 mm is provided in the metal ground layer area through which the first coaxial feed line passes, so as to realize the isolation between the signal and the ground layer. (2) The metasurface emission array also consists of six layers from top to bottom, wherein: The first layer is the patch antenna radiating layer, with the rectangular transmitting metal patch having a square structure of 4.8mm × 6.6mm; The structures of the second to fifth layers are the same as those of the second to fifth layers of the metasurface receiving array. The sixth layer is the microstrip line feed network layer, which is equipped with a third microstrip line feed network formed by microstrip line structure, and has 16 sets of Wilkinson power dividers with isolation resistors that split from one to sixteen channels. The first layer of transmitting metal patch is connected to the third microstrip line feed network of the sixth layer through the second coaxial feed line, and an air isolation hole with a radius of 0.56 mm is provided in the metal ground layer area through which the second coaxial feed line passes.

8. The harmonic generation and beam control method based on amplitude-phase modulated metasurface array according to claim 1, characterized in that, Step 2, which involves constructing the harmonic and beam control model, is detailed below: (1) Time amplitude and phase modulation of harmonic modulation Assume that the amplitude-phase modulated metasurface array receives a point frequency signal. , Represents the imaginary unit. The amplitude of the point frequency signal. The frequency of the point frequency signal. express time; Amplitude-phase modulated metasurface arrays perform periodic amplitude and phase modulation on point frequency signals to obtain... Echo signal at time : (1) in, for The transport coefficient of the metasurface at time t is expressed as: (2) in, The magnitude of change over time. The phase that changes over time; Due to the periodic modulation of the amplitude-phase modulated metasurface array, It is a periodically changing quantity, which can be expanded into a Fourier series as follows: (3) in, For the first The target amplitude value of the first harmonic. For the first The target phase value of the first harmonic; This is the fundamental frequency of the harmonic, which is also the frequency corresponding to the modulation period; By setting the modulation period, the order of the target harmonic, and the relative amplitude and phase of each harmonic, the time-varying transmission coefficient is obtained, and this transmission coefficient is decomposed into amplitudes that vary with time. and phase that changes over time and will , Discretization yields the amplitude and phase control values ​​at each time point, thus forming the amplitude and phase control sequences for each channel; (2) Beam control of target harmonics Assume the metasurface emission array is located at the origin of the three-dimensional spherical coordinate system. There are a total of In this case, the radiated wave propagates in a spherical form and is considered a plane wave under far-field conditions; Let the amplitude of the signal transmitted by each channel be... The initial phase is zero, and the carrier frequency is... Then the first Each element in time Radiated signals Represented as: (4) After adding the modulation obtained in step (1) to the signal of each channel, Represented as: (5) Assuming far-field point Located at the azimuth angle of the array Polar angle ,distance At this location, and satisfying the far-field condition, the amplitude attenuation factor is... Then the far field point Received the Each element in time radiation field Represented as: (6) in The cell period length of the array. The electromagnetic wave wavelength corresponding to the carrier frequency. The speed of light; Far field point The total radiation field received by the array is Individual elements at the far field point The superposition of radiation fields, as expressed by equation (6) using the superposition theorem, is as follows: (7) Assuming control generation The same amplitude and in-phase harmonics of order 1 are sequentially controlled, and the deflection angle of the harmonics is... Then it is necessary to construct The phase is used to satisfy the phase delay caused by the direction deflection. ,for First harmonic, requires modulation to generate coefficients Represented as: (8) Phase term Spatial modulation is required to achieve this; By controlling the phase difference of the harmonics modulated by each array channel in space, the phase difference is made to conform to the phase accumulation relationship determined by the target deflection angle, thereby realizing the beam deflection of the target order harmonics in a specified direction based on the harmonic amplitude and phase control.

9. The harmonic generation and beam control method based on amplitude-phase modulated metasurface array according to claim 1, characterized in that, In step 3, the specific process for generating and loading digital control signals is as follows: The FPGA development board is used to generate and transmit the control signals and control timing required for the amplitude-phase multi-functional RF chip. The control timing is generated based on periodically time-varying amplitude modulation and phase modulation sequences, and converted into a binary timing control flow according to the control logic of the amplitude-phase multi-functional RF chip. The binary timing control flow is imported into the FPGA through a hardware description language programming environment, and data storage and scheduling are performed using IP to generate and output clock signals, transmission signals containing amplitude and phase control data, chip select signals and latch signals that control the amplitude and phase multi-functional RF chip. The FPGA has programmable logic units, memory and communication ports. The system clock frequency of the FPGA is greater than 100MHz, which can generate control signals that meet the timing requirements of the amplitude and phase multi-functional radio frequency chip, and realize independent real-time modulation of the amplitude and phase of each channel in the amplitude and phase modulation module.

10. A harmonic generation and beam control system based on amplitude-phase modulated metasurface array, characterized in that, This system is used to implement the harmonic generation and beam control method based on amplitude-phase modulated metasurface arrays as described in any one of claims 1 to 9. The system includes an amplitude-phase modulated metasurface array construction module, a harmonic and beam control model construction module, a digital control signal generation and loading module, and a target harmonic generation and radiation module. The functions of each module are as follows: Amplitude-phase modulated metasurface array construction module: An amplitude-phase modulated module is constructed using an externally digitally controlled multi-channel amplitude-phase multifunctional radio frequency chip as the core modulating device. The amplitude-phase modulated module is connected to the metasurface receiving array and the metasurface transmitting array respectively to form an amplitude-phase modulated metasurface array. Harmonic and beam control model construction module: Based on the Fourier series expansion principle, for the frequency, amplitude and phase requirements of arbitrary order harmonics of the target, combined with the received point frequency signal carrier frequency, the periodic time-varying amplitude modulation sequence and phase modulation sequence are derived, and matched to the amplitude and phase control range that the amplitude and phase modulation module can achieve; based on the array far-field superposition formula, the scattering field of the column control array is derived, and the phase gradient of each order harmonic is introduced into the column control channel to control the pointing deflection of the corresponding harmonic beam; Digital control signal generation and loading module: Converts the periodically time-varying amplitude, modulation sequence and phase modulation sequence into control codes for the amplitude and phase multi-functional RF chip. The FPGA generates control signals that meet the chip timing constraints, realizing independent real-time modulation of the amplitude and phase of each channel in the amplitude and phase modulation module. Target harmonic generation and radiation module: A transmitting antenna radiates a point-frequency electromagnetic wave, which is captured by the metasurface receiving array, and the resulting radio frequency signal is fed into the amplitude and phase modulation module. Each channel in the amplitude and phase modulation module performs periodic amplitude and phase modulation on the input radio frequency signal according to the corresponding control signal. The modulated signal drives the metasurface emission array, which radiates the generated target harmonics with preset frequency, amplitude and phase in the form of beams by introducing a preset phase gradient between each channel, and guides them to a specified spatial direction.

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