Metasurface structure for reducing normal incident scattering of antenna

Abstract

The invention discloses a metasurface structure for reducing normal incident scattering of an antenna, and the metasurface structure employs a double-layer design, combines an absorption layer and a frequency selection surface layer, and achieves broadband absorption through a periodically two-dimensional unfolded microstrip patch unit and a three-layer resistor loading metal ring. Ansys electromagnetic field simulation software verifies that the structure effectively reduces the radar cross section of the microstrip antenna within the frequency band of 3-10 GHz, and ensures the normal work of the antenna at the same time. Through deep analysis and simulation optimization, key factors influencing the performance are determined, and the balance between the wave permeability and the wave absorbing property is realized. Besides, an adjustable resistance circuit, a reconfigurable mechanism, an intelligent algorithm and a sensor technology are integrated, the stability and the automation level of the antenna performance are further improved, and an effective solution is provided for improving the scattering reduction effect during forward incidence of radar waves.

Description

Technical Field

[0001] The patent of this invention belongs to the field of navigation and communication equipment, and specifically relates to a metasurface structure for reducing the forward incident scattering of an antenna, which is used to reduce the radar scattering cross section of the antenna. Background Art

[0002] Reducing the radar cross section (RCS) of an aircraft can reduce the possibility of the aircraft being detected by radar. The various airborne antennas on the aircraft are typical strong scattering sources, which contribute greatly to the RCS. Reducing the RCS of the airborne antennas is very important.

[0003] Using metasurfaces to reduce antenna scattering is a cutting-edge technology, and frequency selective surface (FSS) is a typical metasurface. By placing periodically arranged FSS units at the front of the antenna, the antenna scattering can be reduced. For microstrip antennas, the FSS is parallel to the antenna plane and placed at the front of the antenna. The antenna's radiation waves can pass through the plane normally, while out-of-band high-frequency radar waves incident at a certain angle will be reflected. The FSS can reduce the RCS in the direction of the wave to a certain extent, but for high-frequency radar waves close to normal incidence, that is, when the direction of the wave is consistent with the antenna method, the high-frequency radar wave is reflected by the FSS along the original path. At this time, the FSS has basically no effect in reducing the RCS.

[0004] In view of the above problems, in order to reduce the RCS of the antenna when the high-frequency radar wave is incident normally, a metasurface is added at a certain distance above the frequency selective surface as an absorbing layer. The absorbing layer is also composed of periodically arranged microstrip patch units, which are used to absorb radar waves outside the antenna working band and outside the passband of the frequency selective surface. Through the action of the two metasurfaces, the absorbing layer and the frequency selective surface, the purpose of reducing the RCS of the antenna when the high-frequency radar wave is incident normally is achieved. Summary of the invention

[0005] The present invention is a metasurface structure for reducing forward incident scattering of an antenna, and is used to solve the problem that the frequency selective surface has a poor effect of reducing antenna scattering when radar waves are incident forward.

[0006] The present application provides a metasurface structure for reducing forward incident scattering of an antenna, comprising: S101, constructing a double-layer planar metasurface structure in which the first layer is an absorption layer and the second layer is a frequency selective surface layer and placing it at the front end of the antenna; S102, designing the absorption layer to be a rectangle with a side length of L1, which is periodically expanded in two dimensions by microstrip patch unit 1; S103, designing the frequency selective surface layer to be a rectangle with the same side length as the absorption layer, and periodically expanding it in two dimensions by the microstrip patch unit 2; S104, simulating the metasurface structure of the antenna's normal incidence scattering using Ansys electromagnetic field simulation software to verify whether the antenna's normal incidence scattering is effectively reduced.

[0007] Preferably, the microstrip patch unit 1 in S102 includes: The microstrip patch unit 1 is a double-layer structure, the first layer is a wave absorbing metal layer, and the second layer is a wave absorbing medium layer.

[0008] Preferably, the microstrip patch unit 1 in S102 further includes: The wave absorbing layer metal layer is composed of three metal rings, the outer metal ring is a polygon with a side length of W1 and a center-to-center alignment; the resonant frequency of the outer metal ring is f1, 3GHz<f1<10GHz; four resistors are loaded on the outer metal ring, and the loading positions of the four resistors are centrally symmetrical; The middle metal ring is a centrally symmetrical polygon, which is consistent with the shape of the outer metal ring and overlaps in the center; the resonant frequency of the middle metal ring is f2, 3GHz<f2<10GHz; four resistors are loaded on the middle metal ring, and the loading positions of the four resistors are centrally symmetrical; The inner metal is a centrally symmetrical polygon, which is consistent with the shape of the outer metal ring and overlaps in the center; it is concave inward based on the shape of the outer metal ring, so that the resonant frequency of the inner metal ring is f3, 3GHz<f3<10GHz; four resistors are loaded on the inner metal ring, and the loading positions of the four resistors are centrally symmetrical.

[0009] Preferably, the wave absorbing layer metal layer is composed of three metal rings, including: The magnitude relationship of the resonant frequencies of the three metal rings is f3<f1<f2; f2 is greater than the operating frequency of the microstrip antenna, which is 2 GHz. The three metal rings resonate at three different frequencies: f1, f2, and f3.

[0010] Preferably, the microstrip patch unit 2 in S103 includes: The microstrip patch unit 2 is a double-layer structure, the first layer is a frequency selective surface layer metal, and the second layer is a frequency selective surface dielectric layer.

[0011] Preferably, the S104 includes: S201, using electromagnetic field theory to theoretically analyze the wave transmission and wave absorption of the frequency selective surface layer, and determine the key factors affecting the two properties; S202, using Ansys electromagnetic field simulation software to simulate and build a simulation model, by adjusting the structural parameters of the frequency selective surface layer, observing the changes in the wave transmission and wave absorption, and finding a preliminary balance point; S203, manufacturing a frequency selective surface layer sample according to the simulation result, and performing an actual radar cross section test and a wave transmission test; S204, comparing the test results with the simulation results, and adjusting the design of the frequency selective surface layer according to the test data.

[0012] Preferably, the step S201 of determining key factors affecting the two properties includes: Metal rings of different shapes, sizes of metal rings, resistance values, unit arrangements of the frequency selective surface layer, dielectric layer loading, incident angles and polarization modes of the incident wave.

[0013] Preferably, the S202 includes: S301, design an adjustable resistance circuit integrated on the metal ring of the frequency selective surface, control the change of the resistance value through an external signal, and dynamically optimize the wave transmission and absorption performance of the frequency selective surface in combination with a control algorithm; S302, designing a reconfigurable mechanism on the basic structure of the frequency selective surface to receive and convert signals through an external control signal interface; S303, combines intelligent algorithms and sensor technology to monitor the environment and antenna performance in real time; S304, integrating the reconfigurable frequency selective surface structure, external control signal interface, intelligent algorithm and sensor technology onto the same hardware platform.

[0014] Preferably, the step S301, combining the degree of association, includes: Determine the basic structure of the frequency selective surface, including the material and arrangement of the metal rings, and use electromagnetic simulation software to simulate the basic structure to verify its basic wave transmission and absorption performance; Determine the adjustment range, accuracy and stability requirements of the resistor and integrate the resistor with the metal ring; Design resistance adjustment circuits including signal reception, signal processing and power management; Design control algorithms based on the application scenarios and requirements of frequency selective surfaces; The adjustable resistance circuit and control program were integrated into the frequency selective surface metal ring, and preliminary resistance adjustment test was carried out.

[0015] Preferably, the S302 includes: Design a mechanical deformation mechanism or an electronic switch reconfigurable mechanism on the basic structure of the frequency selective surface and determine the specific way of reconfiguration; Design an external control signal interface to receive external control signals and convert them into actions of the reconfigurable mechanism. Select the interface type and communication protocol of the wireless interface and wired interface according to the requirements of the reconfigurable mechanism. The reconfigurable mechanism and external control signal interface are integrated into the frequency selective surface infrastructure, and functional tests are performed to verify whether the reconfigurable mechanism can be accurately reconfigured according to the control signal.

[0016] One or more technical solutions provided in this application have at least the following technical effects or advantages: 1. The metasurface structure in the embodiment of the present application innovatively adopts a double-layer design, that is, a combination of an absorption layer and a frequency selective surface layer. This design not only enhances the absorption capacity of high-frequency radar waves outside the operating frequency band of the microstrip antenna, but also ensures that the electromagnetic waves of the antenna can penetrate and radiate normally when the antenna is in operation through the consistency of the frequency selective surface and the operating frequency of the microstrip antenna. In addition, the structure also cleverly utilizes the resonant characteristics of the metal ring loaded with resistance to achieve effective absorption in a wider frequency range, thereby significantly reducing the radar cross section (RCS) of the antenna.

[0017] 2. Verified by Ansys electromagnetic field simulation software, the metasurface structure in this embodiment successfully reduces the RCS of the microstrip antenna by 10dB in the frequency range of 3GHz to 10GHz. This significant reduction effect directly proves the effectiveness of the structure in reducing the normal incidence scattering of the antenna. At the same time, the structure also maintains the normal working performance of the microstrip antenna, ensuring the penetration and radiation of electromagnetic waves. Therefore, this metasurface structure not only improves the stealth performance of the antenna, but also enhances its stability and reliability in complex electromagnetic environments, and has important application value in the fields of radar stealth, wireless communication, etc.

[0018] 3. Through in-depth analysis of electromagnetic field theory and precise simulation of Ansys electromagnetic field simulation software, a comprehensive evaluation and optimization of the wave transmission and absorption of the frequency selective surface layer is achieved. This scheme not only determines the key factors affecting the wave transmission and absorption, such as the shape, size, resistance value and arrangement of the metal ring, but also finds the initial balance point between wave transmission and absorption through parametric design and simulation, providing a solid theoretical foundation for subsequent design and production.

[0019] 4. First, the accuracy of the simulation results is verified through actual radar cross-section tests and wave transmission tests, ensuring the reliability of the design. Secondly, by comparing the test results with the simulation results, errors in the design or processing can be discovered and corrected in a timely manner, improving the performance and design accuracy of the frequency selective surface layer. Finally, this scheme comprehensively considers a variety of factors, such as processing errors, test environment differences, and simplified simulation models, making the design closer to actual applications and having higher practical value and guiding significance.

[0020] 5. By integrating adjustable resistance circuits and intelligent control algorithms, the resistance value of the metal ring of the frequency selective surface can be dynamically adjusted, thereby accurately controlling the wave transmission and absorption performance. At the same time, the introduction of the reconfigurable mechanism enhances the structural flexibility of the frequency selective surface, enabling it to switch between different states according to demand, achieving more precise control of electromagnetic waves.

[0021] 6. The combination of intelligent algorithms and sensor technology enables the system to monitor and optimize the environment and antenna performance in real time. This intelligent adjustment mechanism improves the performance stability of the antenna, reduces the frequency of human intervention, and improves the level of system automation. In addition, all technologies are integrated on the same hardware platform, which simplifies the system structure, reduces application costs, and provides strong support for the widespread application of frequency selective surface technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of a process flow of a metasurface structure for reducing forward incident scattering of an antenna according to an embodiment of the present invention; Figure 2 A schematic diagram of the positional relationship between a double-layer plane and an antenna according to an embodiment of the present invention; Figure 3 It is a side view of a double-layer planar structure of an embodiment of the present invention; Figure 4 A top view of an absorbing layer according to an embodiment of the present invention; Figure 5 It is a top view of the metal absorbing layer of the microstrip patch unit 1 according to an embodiment of the present invention; Figure 6 A top view of the absorbing layer medium of the microstrip patch unit 1 according to an embodiment of the present invention; Figure 7 A top view of a frequency selective surface layer according to an embodiment of the present invention; Figure 8 A top view of a frequency selective surface layer metal of a microstrip patch unit 2 according to an embodiment of the present invention; Fig. 9 A top view of a frequency selective surface layer medium of a microstrip patch unit 2 according to an embodiment of the present invention; Fig.10 4 is a comparison diagram of RCS simulation curves of an embodiment of the present invention. DETAILED DESCRIPTION

[0023] To facilitate the understanding of the present invention, the present application will be described more comprehensively below with reference to the relevant drawings; the drawings show preferred embodiments of the present invention, but the present invention can be implemented in many different forms and is not limited to the embodiments described herein; on the contrary, the purpose of providing these embodiments is to enable a more thorough and comprehensive understanding of the disclosed content of the present invention.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs; the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the term "and / or" used herein includes any and all combinations of one or more related listed items.

[0025] Embodiment 1: like Figure 1 As shown, a metasurface structure for reducing the forward incident scattering of an antenna comprises the following steps: S101, constructing a double-layer planar metasurface structure in which the first layer is an absorption layer and the second layer is a frequency selective surface layer and placing it at the front end of the antenna; Among them, Figure 2 Schematic diagram of the position relationship between the double-layer plane and the antenna Figure 3 The side view of the double-layer plane structure shown, the distance between the two planes is H1=3mm (but not limited to this value); The frequency selective surface layer is equivalent to the floor of the absorption layer. The two work together to absorb the normally incident high-frequency radar waves outside the operating frequency band of the microstrip antenna, thereby enhancing the absorption effect of the high-frequency radar waves. Since the normally incident high-frequency radar waves have the greatest effect on the RCS deterioration of the microstrip antenna, the metasurface structure constructed in this embodiment can greatly reduce the high-frequency RCS. At the same time, the frequency selective surface is consistent with the operating frequency of the microstrip antenna, and the electromagnetic waves radiated by the microstrip antenna can pass through the double-layer plane and radiate normally.

[0026] S102, design the absorption layer to be a rectangle with a side length of L1, which is periodically expanded in two dimensions by microstrip patch unit 1.

[0027] Among them, Figure 4 The top view of the absorbing layer shown is a rectangle with a side length of L1=100 mm, which is periodically two-dimensionally expanded by microstrip patch unit 1, with 9 horizontal expansion numbers and 9 vertical expansion numbers, but not limited to these values; The microstrip patch unit 1 is a double-layer structure, the first layer is a wave absorbing metal layer, and the second layer is a wave absorbing medium layer; The wave absorbing layer metal layer is composed of three metal rings. The outer metal ring is a polygon with a side length of W1 and a center-to-center alignment, including but not limited to a circle, a square, a diamond, etc. The resonant frequency is f1 (3GHz<f1<10GHz), such as Figure 5 The top view of the metal absorbing layer of the microstrip patch unit 1 is shown, the outer metal ring is a center-to-center octagon, but not limited to this shape, the side length W1=8mm, but not limited to this value; four resistors are loaded on the outer metal ring, the four resistor loading positions are centrally symmetrical, and the resistance value is 200 ohms, but not limited to this value; The middle metal ring is a centrally symmetrical polygon, which is consistent with the shape of the outer metal ring and overlaps in the center. The side length is W2=6.8mm, but is not limited to this value. The resonant frequency of the middle metal ring is f2, f2>f1 and 3GHz<f2<10GHz; four resistors are loaded on the middle metal ring, and the four resistor loading positions are centrally symmetrical. The resistance value is 200 ohms, but is not limited to this value; The inner metal is a centrally symmetrical polygon, which is consistent with the shape of the outer metal ring and overlaps at the center. The side length is W3=5.8mm, but not limited to this value. The inner metal ring is concave inward on the basis of the shape of the outer metal ring, so that the resonant frequency of the inner metal ring is f3, and f3<f1, 3GHz<f3<10GHz; four resistors are loaded on the inner metal ring, and the four resistor loading positions are centrally symmetrical. The resistance value is 200 ohms, but not limited to this value; The resonant frequencies of the three metal rings are in the relationship of f3<f1<f2, and f2 is greater than the operating frequency of the microstrip antenna, which is 2GHz. The three metal rings resonate at three different frequencies, f1, f2, and f3, respectively. The three frequencies are close to each other, achieving an absorption bandwidth of 3GHz~10GHz. When resonating, the energy of the incident high-frequency radar wave is converted into current on the metal ring, which is absorbed by the resistor, blocking the scattering of the high-frequency radar wave.

[0028] like Figure 6 The shown microstrip patch unit 1 is a top view of the absorbing layer medium. The absorbing medium layer is a square dielectric plate with a side length W4=11mm and a height H2=3mm, but is not limited to this value.

[0029] S103, designing the frequency selective surface layer to be a rectangle with the same side length as the absorption layer, and periodically expanding it in two dimensions by the microstrip patch unit 2.

[0030] Among them, the microstrip patch unit 2 is a double-layer structure, such as Figure 7 The frequency selective surface layer shown in the top view is periodically expanded two-dimensionally by the microstrip patch unit 2, the number of lateral expansion is 4, and the number of longitudinal expansion is 4, but not limited to this value; Figure 8The top view of the frequency selective surface layer metal of the microstrip patch unit 2 shown, the first layer is the frequency selective surface layer metal, and the second layer is the frequency selective surface dielectric layer; The frequency selective surface layer metal is a copper sheet with a side length of W5=22, but not limited to this value. A centrally symmetrical four-sided ring is etched (the copper sheet is removed), but not limited to this shape; the ring is a quadrilateral with a side length of L2=14.5mm, but not limited to this value; The frequency selective surface layer medium is a square dielectric plate, such as Fig. 9 The top view of the frequency selective surface layer medium of the microstrip patch unit 2 shown has a side length of W5=22mm and a height of H3=3mm, but is not limited to these values.

[0031] S104, simulating the metasurface structure of the antenna's normal incidence scattering using Ansys electromagnetic field simulation software to verify whether the antenna's normal incidence scattering is effectively reduced.

[0032] Specifically, two groups of simulations were performed using Ansys electromagnetic field simulation software. The first group simulated the RCS of microstrip antennas, and the second group simulated the RCS of microstrip antennas loaded with metasurface structures that reduce the normal incidence scattering of the antenna. The results are shown in Figure 2. Fig.10 As shown in the RCS simulation curve comparison diagram, it can be seen from the simulation results that in the range of 3GHz~10GHz, the RCS of the microstrip antenna is -7dBsm, while the RCS of the microstrip antenna loaded with the metasurface structure that reduces the forward incident scattering of the antenna is -17dBsm, indicating that the RCS of the microstrip antenna loaded with the metasurface structure that reduces the forward incident scattering of the antenna is reduced by 10dB, that is, the metasurface structure that reduces the forward incident scattering of the antenna can effectively reduce the forward incident scattering.

[0033] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages: 1. The metasurface structure in the embodiment of the present application innovatively adopts a double-layer design, that is, a combination of an absorption layer and a frequency selective surface layer. This design not only enhances the absorption capacity of high-frequency radar waves outside the operating frequency band of the microstrip antenna, but also ensures that the electromagnetic waves of the antenna can penetrate and radiate normally when the antenna is in operation through the consistency of the frequency selective surface and the operating frequency of the microstrip antenna. In addition, the structure also cleverly utilizes the resonant characteristics of the metal ring loaded with resistance to achieve effective absorption in a wider frequency range, thereby significantly reducing the radar cross section (RCS) of the antenna.

[0034] 2. Verified by Ansys electromagnetic field simulation software, the metasurface structure in this embodiment successfully reduces the RCS of the microstrip antenna by 10dB in the frequency range of 3GHz to 10GHz. This significant reduction effect directly proves the effectiveness of the structure in reducing the normal incidence scattering of the antenna. At the same time, the structure also maintains the normal working performance of the microstrip antenna, ensuring the penetration and radiation of electromagnetic waves. Therefore, this metasurface structure not only improves the stealth performance of the antenna, but also enhances its stability and reliability in complex electromagnetic environments, and has important application value in the fields of radar stealth, wireless communication, etc.

[0035] Embodiment 2: The metasurface structure of the first embodiment above significantly reduces the radar cross section (RCS) of the microstrip antenna by 10 dB in the frequency range of 3 GHz to 10 GHz through a double-layer design (absorption layer and frequency selective surface layer) and the resonance characteristics of the resistor-loaded metal ring, while maintaining the normal working performance of the antenna, improving the stealth performance of the antenna and the stability in complex electromagnetic environments. The double-layer design of the metasurface structure absorbs high-frequency radar waves to reduce RCS, but at the same time it is necessary to ensure that the electromagnetic waves within the working frequency band of the microstrip antenna can be radiated normally. In practical applications, the design of the frequency selective surface layer needs to be carefully adjusted to find the best balance between absorption and reflection. Now further improvements are made to step S104 of the first embodiment, specifically: S201, using electromagnetic field theory to theoretically analyze the wave transmittance and wave absorption of the frequency selective surface layer, and determine the key factors affecting these two properties.

[0036] Among them, the key factors affecting these two properties include: metal rings of different shapes (such as round, square, star, etc.), the size of the metal rings (such as diameter, circumference, etc.), resistance value, unit arrangement of the frequency selective surface layer, dielectric layer loading, incident angle of the incident wave and polarization mode.

[0037] S202, using Ansys electromagnetic field simulation software to simulate and construct a simulation model, by adjusting the structural parameters of the frequency selective surface layer, observing the changes in wave transmittance and wave absorption, and finding a preliminary balance point.

[0038] The structural parameters of the frequency selective surface layer may include the shape, size, resistance value, etc. of the metal ring.

[0039] Specifically, in Ansys, the geometric model of the metal ring, including shape, size and arrangement, needs to be constructed based on the actual structure of the frequency-selective surface layer. Accurate material properties, such as conductivity and dielectric constant, need to be set for the metal ring and dielectric layer. According to actual needs, boundary conditions (such as perfect electric conductor boundary, perfect magnetic conductor boundary) and excitation sources (such as plane wave, point source) of the simulation model need to be set. Using Ansys' APDL parametric design language, adjust the structural parameters of the frequency selective surface layer, including the shape, size, and resistance of the metal ring. After running the simulation, observe the wave transmission and absorption of the frequency selective surface layer under the changes of various parameters. Using Ansys' post-processing function, draw curves such as S parameters, transmission coefficient, and reflection coefficient to analyze the electromagnetic characteristics of the frequency selective surface layer. Based on the simulation results, comprehensively consider and weigh multiple parameters to find the initial balance point between wave transmission and absorption.

[0040] S203, making a frequency selective surface layer sample according to the simulation result, and performing an actual radar cross section test and a wave transmission test.

[0041] Among them, the radar cross section test includes: in the test preparation stage, it is necessary to ensure that the test environment has no other strong electromagnetic interference, fix the frequency selective surface layer sample on the test turntable, and ensure that the relative position between the sample and the test equipment remains constant. Then, according to the specific needs of the test, set the various parameters of the radar cross section tester, covering key factors such as frequency and polarization mode; Start the radar cross-section tester to emit radar waves of specific frequency and polarization. These radar waves must be guaranteed to irradiate the frequency selective surface layer samples to induce scattering signals. The tester receives the scattered signals and calculates the radar cross-section of the samples through internal processing algorithms; records the radar cross-section data obtained from the test, including the results at different frequencies and different polarization modes. Process and analyze the data to evaluate whether the scattering characteristics of the frequency selective surface layer samples meet the design requirements.

[0042] The wave transmission test includes: the test preparation stage, ensuring that there are no other electromagnetic interference sources in the test environment to ensure the accuracy of the test results. The frequency selective surface layer sample is properly placed in the test fixture to ensure that the contact between the sample and the fixture is tight and good. Subsequently, the vector network analyzer is connected to the test fixture, and the test parameters are carefully set, including key information such as frequency range and number of scanning points; During the test, the vector network analyzer is first started to emit electromagnetic waves covering a specific frequency range. After these electromagnetic waves pass through the frequency-selective surface layer sample, part of them is transmitted and the other part is reflected back. The analyzer accurately measures the amplitude and phase information of the transmitted and reflected waves, providing detailed data for subsequent analysis; In the data recording and analysis phase, key data such as the transmission coefficient (S21) and reflection coefficient (S11) obtained from the test are recorded in detail. Based on these data, the wave transmission performance indicators of the frequency selective surface layer samples, such as transmittance and reflectivity, are further calculated. Finally, these data are comprehensively processed and deeply analyzed to objectively evaluate whether the wave transmission performance of the frequency selective surface layer samples meets the design requirements.

[0043] S204, comparing the test results with the simulation results, and adjusting the design of the frequency selective surface layer according to the test data.

[0044] Among them, data comparison includes result comparison (wave transmittance, wave absorption, radar cross-section area) and difference analysis (such as processing errors, test environment differences, simulation model simplification, etc.).

[0045] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages: 1. Through in-depth analysis of electromagnetic field theory and precise simulation of Ansys electromagnetic field simulation software, a comprehensive evaluation and optimization of the wave transmission and absorption of the frequency selective surface layer is achieved. This scheme not only determines the key factors affecting the wave transmission and absorption, such as the shape, size, resistance value and arrangement of the metal ring, but also finds the initial balance point between wave transmission and absorption through parametric design and simulation, providing a solid theoretical foundation for subsequent design and production.

[0046] 2. First, the accuracy of the simulation results is verified through actual radar cross-section tests and wave transmission tests, ensuring the reliability of the design. Secondly, by comparing the test results with the simulation results, errors in the design or processing can be discovered and corrected in a timely manner, improving the performance and design accuracy of the frequency selective surface layer. Finally, this scheme comprehensively considers a variety of factors, such as processing errors, test environment differences, and simplified simulation models, making the design closer to actual applications and having higher practical value and guiding significance.

[0047] Example 3: By combining electromagnetic field theory with Ansys simulation software, the wave transmittance and wave absorption of the frequency selective surface layer are comprehensively evaluated and optimized, key factors are determined, the performance balance point is found, and the reliability of the design is verified through actual tests, thereby improving the design accuracy and practical value. In practical applications, since the working environment of the antenna may change, it is necessary not only to monitor and adjust the antenna in real time, but also to ensure the long-term stability and reliability of the antenna in the frequency selective surface layer. For example, the resistance on the frequency selective surface layer may change due to long-term operation, resulting in a decrease in absorption performance. Therefore, an adjustable resistance technology and a reconfigurable structure technology are constructed to ensure the long-term stability and reliability of the antenna, thereby further effectively absorbing the normally incident high-frequency radar waves outside the working frequency band of the microstrip antenna, thereby significantly reducing the RCS of the antenna and improving the stealth performance of the antenna.

[0048] Now, step S202 of the second embodiment is further improved, specifically: S301, design an adjustable resistance circuit integrated on the metal ring of the frequency selective surface, control the change of the resistance value through an external signal, and dynamically optimize the wave transmission and absorption performance of the frequency selective surface in combination with a control algorithm.

[0049] Specifically, the basic structure of the frequency selective surface is determined, including the material (conductive materials such as copper and aluminum), size (calculated based on the operating frequency and wavelength) and arrangement (periodic arrangement such as square and hexagon) of the metal ring. The basic structure is simulated using electromagnetic simulation software to verify its basic wave transmission and absorption performance. Select the adjustable resistor element AD5290 digital potentiometer or sliding rheostat variable resistor, and determine the adjustment range, accuracy and stability requirements of the resistor according to the design requirements of the frequency selective surface; integrate the resistor with the metal ring to ensure that the resistor can be evenly distributed on the metal ring and does not affect the electromagnetic characteristics of the frequency selective surface; Design a resistance adjustment circuit that includes signal reception, signal processing, and power management. The signal reception part is used to receive external control signals (such as voltage, current, etc.); the signal processing part converts the control signal into a change in resistance value; the power management part ensures stable power supply for the circuit; use circuit simulation software to simulate the circuit to verify its functionality and stability. Based on the simulation results, optimize the circuit design to ensure low noise, low power consumption, and high stability; Design a control algorithm based on the application scenarios and requirements of the frequency selective surface. The algorithm should be able to receive external instructions or sensor data, calculate the required resistance value, and dynamically adjust the resistance through the resistance adjustment circuit. Consider the real-time, accuracy and stability requirements of the algorithm, select the PID control algorithm structure, use the programming language to write the control program, and implement the logic and function of the algorithm; The adjustable resistance circuit and control program are integrated into the metal ring of the frequency selective surface, and a preliminary resistance adjustment test is carried out to verify whether the resistance value can be accurately adjusted according to the control signal. Electromagnetic simulation software is used to verify the influence of the integrated adjustable resistance circuit on the wave transmission and absorption performance of the frequency selective surface.

[0050] S302, designing a reconfigurable mechanism on the basic structure of the frequency selective surface to receive and convert signals through an external control signal interface.

[0051] Specifically, a mechanical deformation mechanism (using mechanical elements such as hinges and slide rails) or an electronic switch (such as PIN diodes, MEMS switches and other electronic elements) is designed on the basic structure of the frequency selective surface to reconfigure the mechanism, and determine the specific way of reconfiguration, such as changing the shape or size of the metal ring through mechanical deformation, or changing the arrangement or connection state of the metal ring through electronic switches; Design an external control signal interface to receive external control signals (such as electromagnetic signals, mechanical forces, etc.) and convert them into actions of the reconfigurable mechanism. According to the requirements of the reconfigurable mechanism, select the appropriate interface type (such as wireless interface, wired interface, etc.) and communication protocol (such as SPI, I2C, etc.), design signal transmission lines and processing circuits, and ensure that the control signal can be accurately and stably transmitted to the reconfigurable mechanism; The reconfigurable mechanism and external control signal interface are integrated into the frequency selective surface infrastructure, and functional tests are performed to verify whether the reconfigurable mechanism can be accurately reconfigured according to the control signal. Electromagnetic simulation software is used to verify the impact of the integrated reconfigurable mechanism on the electromagnetic characteristics of the frequency selective surface.

[0052] S303 combines intelligent algorithms and sensor technology to monitor the environment and antenna performance in real time.

[0053] Specifically, according to the application scenarios and requirements of the frequency selective surface, select the sensor type (such as temperature sensor, humidity sensor, electromagnetic field sensor, etc.) and reasonably design the sensor layout to ensure that the required environmental parameters and antenna performance indicators can be accurately monitored; Combined with sensor technology, design machine learning algorithm intelligent algorithm. The algorithm should be able to monitor sensor data in real time and analyze the changing trends of environmental parameters and antenna performance indicators; based on the monitoring results, the algorithm should be able to automatically adjust the parameters of the frequency selective surface (such as resistance value, structural state, etc.) to optimize the performance of the antenna; Integrate sensors and intelligent algorithms into the frequency selective surface system, conduct preliminary sensor data collection and algorithm testing, verify the accuracy of sensor data and the feasibility of the algorithm. Use experimental testing methods to verify the optimization effect of the integrated intelligent algorithm on the performance of the frequency selective surface.

[0054] S304, integrating the reconfigurable frequency selective surface structure, external control signal interface, intelligent algorithm and sensor technology onto the same hardware platform.

[0055] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages: 1. By integrating adjustable resistance circuits and intelligent control algorithms, the resistance value of the metal ring of the frequency selective surface can be dynamically adjusted, thereby accurately controlling the wave transmission and absorption performance. At the same time, the introduction of the reconfigurable mechanism enhances the structural flexibility of the frequency selective surface, enabling it to switch between different states according to demand, achieving more precise control of electromagnetic waves.

[0056] 2. The combination of intelligent algorithms and sensor technology enables the system to monitor and optimize the environment and antenna performance in real time. This intelligent adjustment mechanism improves the performance stability of the antenna, reduces the frequency of human intervention, and improves the level of system automation. In addition, all technologies are integrated on the same hardware platform, which simplifies the system structure, reduces application costs, and provides strong support for the widespread application of frequency selective surface technology.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A metasurface structure for reducing antenna forward incident scattering, characterized in that: include: S101, constructing a double-layer planar metasurface structure in which the first layer is an absorption layer and the second layer is a frequency selective surface layer and placing it at the front end of the antenna; S102, designing the absorption layer to be a rectangle with a side length of L1, which is periodically expanded in two dimensions by microstrip patch unit 1; S103, designing the frequency selective surface layer to be a rectangle with the same side length as the absorption layer, and periodically expanding it in two dimensions by the microstrip patch unit 2; S104, simulating the metasurface structure of the antenna's normal incidence scattering using Ansys electromagnetic field simulation software to verify whether the antenna's normal incidence scattering is effectively reduced.

2. The metasurface structure for reducing antenna forward incident scattering according to claim 1, characterized in that: The microstrip patch unit 1 in S102 includes: The microstrip patch unit 1 is a double-layer structure, the first layer is a wave absorbing metal layer, and the second layer is a wave absorbing medium layer.

3. The metasurface structure for reducing antenna forward incident scattering according to claim 1, characterized in that: The microstrip patch unit 1 in S102 further includes: The wave absorbing layer metal layer is composed of three metal rings, the outer metal ring is a polygon with a side length of W1 and a center-to-center alignment; the resonant frequency of the outer metal ring is f1, 3GHz<f1<10GHz; four resistors are loaded on the outer metal ring, and the loading positions of the four resistors are centrally symmetrical; The middle metal ring is a centrally symmetrical polygon, which is consistent with the shape of the outer metal ring and overlaps in the center; the resonant frequency of the middle metal ring is f2, 3GHz<f2<10GHz; four resistors are loaded on the middle metal ring, and the loading positions of the four resistors are centrally symmetrical; The inner metal is a centrally symmetrical polygon, which is consistent with the shape of the outer metal ring and overlaps in the center; it is concave inward based on the shape of the outer metal ring, so that the resonant frequency of the inner metal ring is f3, 3GHz<f3<10GHz; four resistors are loaded on the inner metal ring, and the loading positions of the four resistors are centrally symmetrical.

4. The metasurface structure for reducing antenna forward incident scattering according to claim 3, characterized in that: The wave absorbing layer metal layer is composed of three metal rings, including: The magnitude relationship of the resonant frequencies of the three metal rings is f3<f1<f2; f2 is greater than the operating frequency of the microstrip antenna, which is 2 GHz. The three metal rings resonate at three different frequencies: f1, f2, and f3.

5. The metasurface structure for reducing antenna forward incident scattering according to claim 1, characterized in that: The microstrip patch unit 2 in S103 includes: The microstrip patch unit 2 is a double-layer structure, the first layer is a frequency selective surface layer metal, and the second layer is a frequency selective surface dielectric layer.

6. The metasurface structure for reducing antenna forward incident scattering according to claim 1, characterized in that: The S104 includes: S201, using electromagnetic field theory to theoretically analyze the wave transmission and wave absorption of the frequency selective surface layer, and determine the key factors affecting the two properties; S202, using Ansys electromagnetic field simulation software to simulate and build a simulation model, by adjusting the structural parameters of the frequency selective surface layer, observing the changes in the wave transmission and wave absorption, and finding a preliminary balance point; S203, manufacturing a frequency selective surface layer sample according to the simulation result, and performing an actual radar cross section test and a wave transmission test; S204, comparing the test results with the simulation results, and adjusting the design of the frequency selective surface layer according to the test data.

7. The metasurface structure for reducing antenna forward incident scattering according to claim 6, characterized in that: The step S201 determines the key factors affecting the two properties, including: Metal rings of different shapes, sizes of metal rings, resistance values, unit arrangements of the frequency selective surface layer, dielectric layer loading, incident angles and polarization modes of the incident wave.

8. The metasurface structure for reducing antenna forward incident scattering according to claim 6, characterized in that: The S202 includes: S301, design an adjustable resistance circuit integrated on the metal ring of the frequency selective surface, control the change of the resistance value through an external signal, and dynamically optimize the wave transmission and absorption performance of the frequency selective surface in combination with a control algorithm; S302, designing a reconfigurable mechanism on the basic structure of the frequency selective surface to receive and convert signals through an external control signal interface; S303, combines intelligent algorithms and sensor technology to monitor the environment and antenna performance in real time; S304, integrating the reconfigurable frequency selective surface structure, external control signal interface, intelligent algorithm and sensor technology onto the same hardware platform.

9. The metasurface structure for reducing antenna forward incident scattering according to claim 8, characterized in that: The step S301, combining the degree of association, includes: Determine the basic structure of the frequency selective surface, including the material and arrangement of the metal rings, and use electromagnetic simulation software to simulate the basic structure to verify its basic wave transmission and absorption performance; Determine the adjustment range, accuracy and stability requirements of the resistor and integrate the resistor with the metal ring; Design resistance adjustment circuits including signal reception, signal processing and power management; Design control algorithms based on the application scenarios and requirements of frequency selective surfaces; The adjustable resistance circuit and control program were integrated into the frequency selective surface metal ring, and preliminary resistance adjustment test was carried out.

10. The metasurface structure for reducing antenna forward incident scattering according to claim 8, characterized in that: The S302 includes: Design a mechanical deformation mechanism or an electronic switch reconfigurable mechanism on the basic structure of the frequency selective surface and determine the specific way of reconfiguration; Design an external control signal interface to receive external control signals and convert them into actions of the reconfigurable mechanism. Select the interface type and communication protocol of the wireless interface and wired interface according to the requirements of the reconfigurable mechanism. The reconfigurable mechanism and external control signal interface are integrated into the frequency selective surface infrastructure, and functional tests are performed to verify whether the reconfigurable mechanism can be accurately reconfigured according to the control signal.

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