Metasurface structure for reducing normal incident scattering of antenna

Abstract

The utility model 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 application belongs to the field of navigation communication equipment, and particularly relates to a metasurface structure for reducing normal incidence scattering of an antenna. BACKGROUND

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

[0003] Using a metasurface to reduce the scattering of an antenna is a relatively advanced technical means at present, and a frequency selective surface (FSS) is a typical metasurface. By placing a periodically arranged FSS unit at the front end of an antenna, the scattering of the antenna can be reduced. For a microstrip antenna, the FSS is parallel to the antenna plane and is placed at the front end of the antenna. The radiated wave of the antenna can normally pass through the plane, while the out-of-band high-frequency radar wave incident at a certain angle will be reflected. The FSS can reduce the RCS in the direction of the incoming wave to a certain extent, but when the high-frequency radar wave is close to normal incidence, that is, the direction of the incoming wave is consistent with the antenna method, the high-frequency radar wave is reflected along the original path by the FSS. At this time, the FSS has little effect on 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 normally incident, a metasurface is added as an absorbing layer at a certain distance above the FSS. The absorbing layer is also composed of periodically arranged microstrip patch units, which are used to absorb radar waves outside the antenna operating frequency band and outside the passband of the FSS. Through the action of the absorbing layer and the FSS, the RCS of the antenna when the high-frequency radar wave is normally incident is reduced. SUMMARY

[0005] The application is a metasurface structure for reducing the normal incidence scattering of an antenna, which is used to solve the problem that the FSS has poor effect on reducing the scattering of an antenna when the radar wave is normally incident.

[0006] The application provides a metasurface structure for reducing the normal incidence scattering of an antenna, which comprises:

[0007] S101, a double-layer planar metasurface structure with the first layer being an absorbing layer and the second layer being an FSS layer is placed at the front end of the antenna;

[0008] S102, the absorbing layer is designed to be rectangular with a side length of L1, and is periodically two-dimensionally expanded by microstrip patch units I.

[0009] S103, the frequency selective surface layer is designed as a rectangle with the same side length as the absorbing layer, and is periodically and two-dimensionally developed by the microstrip patch unit II;

[0010] S104, the metasurface structure for the antenna normal incidence scattering is simulated by using the Ansys electromagnetic field simulation software to verify whether the antenna normal incidence scattering is effectively reduced.

[0011] Preferably, the S102, the microstrip patch unit I, comprises:

[0012] The microstrip patch unit I is a double-layer structure, the first layer is a wave-absorbing metal layer, and the second layer is a wave-absorbing dielectric layer.

[0013] Preferably, the S102, the microstrip patch unit I, further comprises:

[0014] The wave-absorbing metal layer is composed of three metal rings, the outer metal ring is a center-symmetric polygon with a side length of W1; the resonant frequency of the outer metal ring is f1, 3GHz < f1 < 10GHz; four resistors are loaded on the outer metal ring, and the four resistor loading positions are center-symmetric;

[0015] The middle metal ring is a center-symmetric polygon, the shape of the middle metal ring is consistent with the shape of the outer metal ring and the centers overlap; the resonant frequency of the middle metal ring is f2, 3GHz < f2 < 10GHz; four resistors are loaded on the middle metal ring, and the four resistor loading positions are center-symmetric;

[0016] The inner metal ring is a center-symmetric polygon, the shape of the inner metal ring is consistent with the shape of the outer metal ring and the centers overlap; the inner metal ring is recessed inward on the basis of 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 four resistor loading positions are center-symmetric.

[0017] Preferably, the wave-absorbing metal layer is composed of three metal rings, comprising:

[0018] The resonant frequencies of the three metal rings satisfy the relationship f3 < f1 < f2;

[0019] f2 is greater than the working frequency of the microstrip antenna, and the working frequency of the microstrip antenna is 2GHz;

[0020] The three metal rings resonate at three different frequencies f1, f2 and f3, respectively.

[0021] Preferably, the S103, the microstrip patch unit II, comprises:

[0022] The microstrip patch unit II is a double-layer structure, the first layer is a frequency selective surface metal layer, and the second layer is a frequency selective surface dielectric layer.

[0023] Preferably, the S104 comprises:

[0024] S201, theoretically analyzing the wave permeability and wave absorption of the frequency selective surface layer by using electromagnetic field theory, and determining the key factors affecting the two performances;

[0025] S202, simulating and constructing a simulation model by using Ansys electromagnetic field simulation software, observing the changes of the wave permeability and wave absorption by adjusting the structural parameters of the frequency selective surface layer, and finding a preliminary balance point;

[0026] S203, manufacturing a frequency selective surface layer sample according to the simulation results, and performing actual radar cross section test and wave permeability test;

[0027] S204, comparing the test results with the simulation results, and adjusting the design of the frequency selective surface layer according to the test data.

[0028] Preferably, the S201 comprises:

[0029] Different shapes of metal rings, sizes of metal rings, resistance values, unit arrangement modes of the frequency selective surface layer, dielectric layer loading, incident angles and polarization modes of incident waves.

[0030] Preferably, the S202 comprises:

[0031] S301, designing an adjustable resistance circuit integrated on the metal ring of the frequency selective surface, controlling the resistance value change through an external signal, and dynamically optimizing the wave permeability and wave absorption performance of the frequency selective surface by combining a control algorithm;

[0032] S302, designing a reconfigurable mechanism on the basis structure of the frequency selective surface, receiving and converting signals through an external control signal interface;

[0033] S303, combining intelligent algorithms and sensor technologies to monitor the environment and antenna performance in real time;

[0034] S304, integrating the reconfigurable frequency selective surface structure, the external control signal interface, the intelligent algorithm and the sensor technology into the same hardware platform.

[0035] Preferably, the S301 comprises:

[0036] Determining the basic structure of the frequency selective surface, including the material and arrangement mode of the metal ring, simulating the basic structure by using electromagnetic simulation software, and verifying the basic wave permeability and wave absorption performance;

[0037] Determine the adjustment range, precision and stability requirements of the resistance, integrate the resistance with the metal ring;

[0038] Design a resistance adjustment circuit containing signal reception, signal processing and power management;

[0039] According to the application scene and demand of the frequency selective surface, design the control algorithm;

[0040] Integrate the adjustable resistance circuit and control program into the metal ring of the frequency selective surface, and conduct preliminary resistance adjustment test.

[0041] Preferably, the S302 comprises:

[0042] Design a mechanical deformation mechanism or an electronic switch reconfigurable mechanism on the basis structure of the frequency selective surface, and determine the specific way of reconfiguration;

[0043] Design an external control signal interface for receiving external control signals and converting them into actions of the reconfigurable mechanism, and select the interface type and communication protocol of the wireless interface or wired interface according to the demand of the reconfigurable mechanism;

[0044] Integrate the reconfigurable mechanism and the external control signal interface into the basis structure of the frequency selective surface, and conduct function test to verify whether the reconfigurable mechanism can accurately reconfigure according to the control signals.

[0045] The one or more technical solutions provided in the application have at least the following technical effects or advantages:

[0046] 1. The metasurface structure in the embodiment of the application innovatively adopts a double-layer design, i.e., the 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 working frequency band of the microstrip antenna, but also ensures that electromagnetic waves can normally penetrate and radiate in the working state of the antenna through the consistency of the frequency selective surface and the working frequency of the microstrip antenna. In addition, the structure also ingeniously utilizes the resonance characteristics of the resistance-loaded metal ring to achieve effective absorption in a wide frequency range, thereby significantly reducing the radar cross section (RCS) of the antenna.

[0047] 2. According to the verification of the Ansys electromagnetic field simulation software, the metasurface structure in the embodiment successfully reduces the RCS of the microstrip antenna by 10 dB in the frequency range of 3 GHz to 10 GHz. 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, which has important application value in the fields of radar stealth, wireless communication, etc.

[0048] 3、Through in-depth analysis of electromagnetic field theory and precise simulation of Ansys electromagnetic field simulation software, comprehensive evaluation and optimization of the wave permeability and wave absorption of the frequency selective surface layer are realized. This scheme not only determines the key factors affecting the wave permeability and wave absorption, such as the shape, size, resistance value and arrangement of the metal ring, but also finds the preliminary balance point between wave permeability and wave absorption through parameterized design and simulation, providing a solid theoretical basis for subsequent design and production.

[0049] 4、Firstly, the accuracy of the simulation results is verified through actual radar cross section test and wave permeability test, ensuring the reliability of the design. Secondly, by comparing the test results with the simulation results, errors in design or processing can be found and corrected in time, improving the performance and design accuracy of the frequency selective surface layer. Finally, this scheme takes into account various factors such as processing errors, differences in test environment, and simplification of simulation models, making the design more practical and having higher practical value and guiding significance.

[0050] 5、By integrating adjustable resistance circuit and intelligent control algorithm, the resistance value of the frequency selective surface metal ring can be dynamically adjusted, thus precisely controlling the wave permeability and wave absorption performance. At the same time, the introduction of 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.

[0051] 6、The combination of intelligent algorithm 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 human intervention frequency, and improves the automation level of the system. In addition, all technologies are integrated into the same hardware platform, simplifying the system structure and reducing application costs, providing strong support for the widespread application of frequency selective surface technology. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 Flowchart of a super surface structure for reducing the normal incidence scattering of an antenna according to an embodiment of the present application;

[0053] Figure 2 Schematic diagram of the position relationship between the double-layer plane and the antenna according to an embodiment of the present application;

[0054] Figure 3 Side view of the double-layer plane structure according to an embodiment of the present application;

[0055] Figure 4 Top view of the wave absorption layer according to an embodiment of the present application;

[0056] Figure 5 Top view of the wave absorption layer metal of the microstrip patch unit I according to an embodiment of the present application;

[0057] Figure 6 A microstrip patch unit I wave-absorbing layer medium top view of an embodiment of the present application;

[0058] Figure 7 A frequency selective surface layer top view of an embodiment of the present application;

[0059] Figure 8 A microstrip patch unit II frequency selective surface layer metal top view of an embodiment of the present application;

[0060] Figure 9 A microstrip patch unit II frequency selective surface layer medium top view of an embodiment of the present application;

[0061] Figure 10 An RCS simulation curve comparison diagram of an embodiment of the present application. DETAILED DESCRIPTION

[0062] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings, in which preferred embodiments of the present application are shown; however, the present application can be realized in many different forms and is not limited to the embodiments described herein; on the contrary, these embodiments are provided so that the disclosure of the present application can be more thoroughly and completely understood.

[0063] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application; the term "and / or" used herein includes any and all combinations of one or more related listed items. EMBODIMENT

[0064] As shown in Figure 1 , a metasurface structure for reducing the normal incidence scattering of an antenna includes the following steps:

[0065] S101, a double-layer planar metasurface structure with the first layer as an absorbing layer and the second layer as a frequency selective surface layer is placed in front of the antenna;

[0066] As shown in Figure 2 , a double-layer planar and antenna position relationship diagram and Figure 3 , a double-layer planar structure side view, the distance between the two layers is H1=3mm (but not limited to this value);

[0067] The frequency-selective surface layer acts as the floor of the absorption layer. Together, they can absorb normally incident high-frequency radar waves outside the operating frequency band of the microstrip antenna, thus enhancing the absorption effect of high-frequency radar waves. Since normally incident high-frequency radar waves have the greatest deterioration effect on the RCS 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 has the same operating frequency as the microstrip antenna, and the electromagnetic waves radiated by the microstrip antenna can pass through the double-layer plane and radiate normally.

[0068] S102, the absorption layer is designed to be rectangular with a side length of L1, and is periodically unfolded in two dimensions by microstrip patch unit I.

[0069] Among them, such as Figure 4 The top view of the absorbing layer shown is a rectangle with a side length of L1=100mm, which is periodically unfolded in two dimensions by microstrip patch unit I. The number of horizontal unfolding units is 9, and the number of vertical unfolding units is 9, but not limited to these values.

[0070] The microstrip patch unit I has a two-layer structure, with the first layer being an absorbing metal layer and the second layer being an absorbing dielectric layer;

[0071] The absorbing metal layer consists of three metal rings. The outermost metal ring is a polygon with a side length W1, centered on each other, including but not limited to circles, squares, rhombuses, etc., with a resonant frequency of f1 (3GHz < f1 < 10GHz). Figure 5 The diagram shows a top view of the absorbing layer metal of microstrip patch unit I. The outer metal ring is a centered octagon, but not limited to this shape, with a side length W1 = 8 mm, but not limited to this value. Four resistors are loaded on the outer metal ring, with the four resistors being centrally symmetrically positioned and having a resistance value of 200 ohms, but not limited to this value.

[0072] The middle metal ring is a centrally symmetrical polygon, which has the same shape as the outer metal ring and overlaps in the center. Here, the side length is W2 = 6.8 mm, but it is not limited to this value. The resonant frequency of the middle metal ring is f2, f2 > f1 and 3 GHz < f2 < 10 GHz. Four resistors are loaded on the middle metal ring. The four resistors are loaded in a centrally symmetrical position. The resistance value is 200 ohms, but it is not limited to this value.

[0073] The inner metal is a centrally symmetrical polygon, which is identical in shape to the outer metal ring and overlaps in the center. Here, the side length is W3 = 5.8 mm, but it is not limited to this value. 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, and f3 < f1, 3 GHz < f3 < 10 GHz. Four resistors are loaded on the inner metal ring. The four resistors are loaded in a centrally symmetrical position, and the resistance value is 200 ohms, but it is not limited to this value.

[0074] The resonant frequencies of the three metal rings are in the order f3 < f1 < f2, with f2 being 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), which are close to each other, achieving an absorption bandwidth of 3 GHz to 10 GHz. At resonance, the energy of the incident high-frequency radar wave is converted into a current on the metal rings, which is then absorbed by the resistors, thus blocking the scattering of the high-frequency radar wave.

[0075] like Figure 6 The diagram shows a top view of the absorbing medium of microstrip patch unit I. The absorbing medium is a square dielectric plate with a side length W4=11mm and a height H2=3mm, but is not limited to these values.

[0076] S103, the design frequency selects the surface layer as a rectangle with the same side length as the absorption layer, which is periodically unfolded in two dimensions by microstrip patch unit II.

[0077] Among them, the microstrip patch unit II has a double-layer structure, such as Figure 7 The frequency selection shown is a top view of the surface layer, which is periodically unfolded in two dimensions by microstrip patch unit II. The number of unfolded units is 4 in the horizontal direction and 4 in the vertical direction, but is not limited to these values; for example... Figure 8 The top view of the frequency selection surface layer metal of the microstrip patch unit II shown is shown. The first layer is the frequency selection surface layer metal, and the second layer is the frequency selection surface dielectric layer.

[0078] The frequency is selected for the surface layer metal, which is a copper sheet with a side length of W5=22, but not limited to this value. A centrally symmetrical quadrilateral ring is etched (the copper sheet is removed) on the copper sheet, 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.

[0079] The frequency-selective surface layer dielectric is a square dielectric plate, such as... Figure 9 The microstrip patch unit II shown is a top view of the surface layer dielectric for frequency selection. The side length is W5=22mm and the height is H3=3mm, but it is not limited to these values.

[0080] S104 uses Ansys electromagnetic field simulation software to simulate the metasurface structure that causes normal incident scattering of the antenna, and verifies whether it effectively reduces normal incident scattering of the antenna.

[0081] Specifically, two sets of simulations were performed using Ansys electromagnetic field simulation software. The first set simulated the RCS of the microstrip antenna, and the second set simulated the RCS of the microstrip antenna by loading a metasurface structure to reduce normal incident scattering. The results are as follows: Figure 10The RCS simulation curve contrast diagram shown, from the simulation results can be seen that, in 3GHz~10GHz, the RCS of the microstrip antenna is-7dBsm, and the RCS of the microstrip antenna loaded with the super surface structure reducing the normal incidence scattering of the antenna is-17dBsm, which shows that the RCS of the microstrip antenna loaded with the super surface structure reducing the normal incidence scattering of the antenna is reduced by 10dB, that is, the super surface structure reducing the normal incidence scattering of the antenna can effectively reduce the normal incidence scattering.

[0082] The technical solutions in the embodiments of the application have at least the following technical effects or advantages:

[0083] 1. The super surface structure in the embodiments of the application innovatively adopts a double-layer design, that is, the 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 working frequency band of the microstrip antenna, but also ensures that electromagnetic waves can normally penetrate and radiate in the working state of the antenna through the consistency of the frequency selective surface and the working frequency of the microstrip antenna. In addition, the structure also ingeniously utilizes the resonance characteristics of the resistance-loaded metal ring to achieve effective absorption in a wide frequency range, thereby significantly reducing the radar cross section (RCS) of the antenna.

[0084] 2. Through the verification of the Ansys electromagnetic field simulation software, the super surface structure in the embodiments 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 super surface structure not only improves the stealth performance of the antenna, but also enhances its stability and reliability in complex electromagnetic environments, which has important application value in the fields of radar stealth, wireless communication, etc. Embodiment

[0085] The super surface structure of the above embodiment one reduces the radar cross section (RCS) of the microstrip antenna by 10dB in the frequency range of 3GHz to 10GHz through the double-layer design (absorption layer and frequency selective surface layer) and the resonance characteristics of the resistance-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 super surface structure absorbs high-frequency radar waves to reduce the RCS, but at the same time needs to ensure that electromagnetic waves in the working frequency band of the microstrip antenna can normally radiate. In actual application, the design of the frequency selective surface layer needs to be carefully adjusted to find the best balance between absorption and reflection. Now the step S104 of embodiment one is further improved, specifically:

[0086] S201, theoretically analyze the wave-transmitting property and wave-absorbing property of the frequency selective surface layer using electromagnetic field theory, and determine the key factors affecting the two properties.

[0087] The key factors affecting the two properties include: different shapes of metal rings (such as circular, square, star-shaped, etc.), the size of the metal ring (such as diameter, circumference, etc.), resistance value, unit arrangement of the frequency selective surface layer, dielectric layer loading, incident angle and polarization of the incident wave.

[0088] S202, simulate and construct a simulation model using Ansys electromagnetic field simulation software, adjust the structural parameters of the frequency selective surface layer, observe the changes in wave-transmitting property and wave-absorbing property, and find the preliminary balance point.

[0089] The structural parameters of the frequency selective surface layer can include the shape, size, and resistance value of the metal ring.

[0090] Specifically, in Ansys, the geometric model of the metal ring needs to be constructed according to the actual structure of the frequency selective surface layer, including shape, size, and arrangement. Accurate material properties are set for the metal ring and the dielectric layer, such as electrical conductivity and dielectric constant. According to actual requirements, set the boundary conditions (such as perfect electrical conductor boundary, perfect magnetic conductor boundary) and excitation sources (such as plane wave, point source) of the simulation model;

[0091] Use Ansys's APDL parameterized design language to adjust the structural parameters of the frequency selective surface layer, including the shape, size, and resistance value of the metal ring. After running the simulation, observe the wave-transmitting property and wave-absorbing property of the frequency selective surface layer under the changes of each parameter. Use Ansys's post-processing function to draw S parameter, transmission coefficient, reflection coefficient, etc. curves to analyze the electromagnetic characteristics of the frequency selective surface layer. According to the simulation results, consider and balance multiple parameters to find the preliminary balance point between wave-transmitting property and wave-absorbing property.

[0092] S203, according to the simulation results, make frequency selective surface layer samples, and perform actual radar cross section test and wave-transmitting property test.

[0093] The radar cross section test includes: in the test preparation stage, ensure that the test environment is free of 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 is constant. Then, according to the specific requirements of the test, set the parameters of the radar cross section tester, including frequency, polarization mode, and other key elements;

[0094] Start the radar cross section tester, emit radar waves of specific frequency and polarization. These radar waves must ensure that they illuminate the frequency selective surface layer sample, inducing the generation of scattered signals. The tester receives the scattered signals and calculates the radar cross section of the sample through internal processing algorithms; record the radar cross section data obtained by testing, including the results under different frequencies and different polarization modes. Process and analyze the data to evaluate whether the scattering characteristics of the frequency selective surface layer sample meet the design requirements.

[0095] The wave transparency test includes: the test preparation stage, ensuring that the test environment is free of other electromagnetic interference sources to ensure the accuracy of the test results. The frequency selective surface layer sample is properly placed in the test fixture, ensuring that the sample is in close contact with the fixture. Then, connect the vector network analyzer with the test fixture and carefully set the test parameters, including the frequency range, scan point number and other key information;

[0096] Enter the test process, first start the vector network analyzer, emit electromagnetic waves covering a specific frequency range. After these electromagnetic waves pass through the frequency selective surface layer sample, part of them are 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;

[0097] In the data recording and analysis section, record the transmission coefficient (S21) and reflection coefficient (S11) and other key data obtained by testing in detail. Based on these data, further calculate the wave transmission performance indicators of the frequency selective surface layer sample, such as transmittance, reflectance, etc. Finally, comprehensively process and deeply analyze these data to objectively evaluate whether the wave transmission performance of the frequency selective surface layer sample meets the design requirements.

[0098] S204, compare the test results with the simulation results, and adjust the design of the frequency selective surface layer according to the test data.

[0099] Among them, the data comparison includes result comparison (wave transparency, wave absorption, radar cross section) and difference analysis (such as processing error, test environment difference, simulation model simplification, etc.).

[0100] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages:

[0101] 1. Through in-depth analysis of electromagnetic field theory and accurate simulation of Ansys electromagnetic field simulation software, the wave transparency and wave absorption of the frequency selective surface layer are comprehensively evaluated and optimized. This scheme not only determines the key factors affecting wave transparency and wave absorption, such as the shape, size, resistance value and arrangement of the metal ring, but also finds the preliminary balance point between wave transparency and wave absorption through parameterized design and simulation, providing a solid theoretical basis for subsequent design and production.

[0102] 2、Firstly, the accuracy of the simulation results is verified through actual radar cross-section tests and wave permeability 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 found and corrected in a timely manner, improving the performance and design accuracy of the frequency selective surface layer. Finally, this scheme takes into account various factors such as processing errors, differences in test environments, and simplification of simulation models, making the design more practical and having higher practical value and guiding significance.

[0103] Example Three: By combining electromagnetic field theory and Ansys simulation software, the wave permeability and wave absorption of the frequency selective surface layer are comprehensively evaluated and optimized, the key factors are determined, the performance balance point is found, and the reliability of the design is verified through actual tests, improving the design accuracy and practical value. In practical applications, the working environment of the antenna may change, so not only real-time monitoring and adjustment of the antenna are needed, but also long-term stability and reliability of the frequency selective surface layer antenna. For example, the resistance on the frequency selective surface layer may change over time, leading to a decrease in absorption performance. Therefore, a technology for adjusting resistance and a reconfigurable structure are constructed to ensure the long-term stability and reliability of the antenna, thereby further effectively absorbing incident high-frequency radar waves outside the working frequency band of the microstrip antenna, significantly reducing the RCS of the antenna, and improving the stealth performance of the antenna.

[0104] Now further improve the step S202 of example two, specifically:

[0105] S301, design a adjustable resistance circuit integrated on the frequency selective surface metal ring, control the resistance value change through external signal, combine with control algorithm to dynamically optimize the wave permeability and wave absorption performance of the frequency selective surface.

[0106] Specifically, determine the basic structure of the frequency selective surface, including the material of the metal ring (such as copper, aluminum and other conductive materials), the size (calculated according to the working frequency and wavelength), and the arrangement (such as square, hexagonal periodic arrangement), use electromagnetic simulation software to simulate the basic structure, verify its basic wave permeability and wave absorption performance;

[0107] Select adjustable resistance element AD5290 digital potentiometer or variable resistor, according to the design requirements of the frequency selective surface, determine the adjustment range, accuracy and stability requirements of the resistance; integrate the resistance with the metal ring to ensure that the resistance can be evenly distributed on the metal ring and does not affect the electromagnetic properties of the frequency selective surface;

[0108] 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 and verify its functionality and stability. According to the simulation results, optimize the circuit design to ensure low noise, low power consumption and high stability;

[0109] According to the application scenario and demand of the frequency selective surface, design the control algorithm. The algorithm should be able to receive external instructions or sensor data, calculate the required resistance value, and adjust the resistance dynamically through the resistance adjustment circuit. Considering the real-time, accuracy and stability requirements of the algorithm, select the PID control algorithm structure, use programming language to write the control program, and realize the logic and function of the algorithm;

[0110] Integrate the adjustable resistance circuit and control program into the metal ring of the frequency selective surface, and perform preliminary resistance adjustment test to verify whether the resistance value can be accurately adjusted according to the control signal. Use electromagnetic simulation software to verify the influence of the integrated adjustable resistance circuit on the wave transmission and absorption performance of the frequency selective surface.

[0111] S302, design a reconfigurable mechanism on the basis of the frequency selective surface structure, and receive and convert signals through an external control signal interface.

[0112] Specifically, design a mechanical deformation mechanism (using hinge, slide rail, etc. mechanical elements) or electronic switch (such as PIN diode, MEMS switch, etc. electronic elements) reconfigurable mechanism on the basis of the frequency selective surface structure, 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 switch;

[0113] Design an external control signal interface for receiving external control signals (such as electromagnetic signals, mechanical forces, etc.) and converting them into actions of the reconfigurable mechanism. According to the requirements of the reconfigurable mechanism, select appropriate interface types (such as wireless interface, wired interface, etc.) and communication protocols (such as SPI, I2C, etc.), design signal transmission lines and processing circuits to ensure that the control signal can be accurately and stably transmitted to the reconfigurable mechanism;

[0114] Integrate the reconfigurable mechanism and external control signal interface into the frequency selective surface structure, and perform function test to verify whether the reconfigurable mechanism can accurately reconfigure according to the control signal. Use electromagnetic simulation software to verify the influence of the integrated reconfigurable mechanism on the electromagnetic characteristics of the frequency selective surface.

[0115] S303, combine intelligent algorithm and sensor technology to monitor the environment and antenna performance in real time.

[0116] Specifically, according to the application scenarios and requirements of the frequency selective surface, the sensor type (such as temperature sensor, humidity sensor, electromagnetic field sensor, etc.) is selected, and the sensor layout is reasonably designed to ensure that the required environmental parameters and antenna performance indicators can be accurately monitored.

[0117] In combination with the sensor technology, a machine learning algorithm is designed. The algorithm should be able to monitor the sensor data in real time, analyze the trend of environmental parameters and antenna performance indicators; according to the monitoring results, the algorithm should be able to automatically adjust the parameters of the frequency selective surface (such as resistance value, structure state, etc.) to optimize the performance of the antenna;

[0118] Integrate the sensor and intelligent algorithm into the frequency selective surface system, perform preliminary sensor data collection and algorithm testing, and verify the accuracy of the 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.

[0119] S304, integrate the reconfigurable frequency selective surface structure, external control signal interface, intelligent algorithm and sensor technology into the same hardware platform.

[0120] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages:

[0121] 1. By integrating adjustable resistance circuit and intelligent control algorithm, the resistance value of the frequency selective surface metal ring can be dynamically adjusted, thereby precisely controlling the wave transmission and wave absorption performance. At the same time, the introduction of reconfigurable mechanism enhances the structural flexibility of the frequency selective surface, enabling it to switch between different states according to requirements, achieving more precise control of electromagnetic waves.

[0122] 2. The combination of intelligent algorithm 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 human intervention frequency, and improves the automation level of the system. In addition, all technologies are integrated into the same hardware platform, simplifying the system structure and reducing application costs, providing strong support for the widespread application of frequency selective surface technology.

[0123] The above description is only the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A metasurface structure for reducing normal-incidence scattering of an antenna, the metasurface structure comprising: The application relates to a double-layer planar metasurface structure comprising: a first layer is an absorbing layer, and a second layer is a frequency selective surface layer, which is placed in front of an antenna; the absorbing layer is rectangular with a side length of L1 and is periodically two-dimensionally expanded by microstrip patch units I; the microstrip patch units I are double-layer structures, the first layer is an absorbing layer metal, and the second layer is an absorbing layer dielectric; the frequency selective surface layer is rectangular with the same side length as the absorbing layer and is periodically two-dimensionally expanded by microstrip patch units II; the microstrip patch units II are double-layer structures, the first layer is a frequency selective surface layer metal, and the second layer is a frequency selective surface layer dielectric.

2. The metasurface structure of claim 1, wherein, The microstrip patch units I further comprise: the absorbing layer metal layer is composed of three metal rings, the outer metal ring is a center-symmetric polygon with a side length of W1; the resonant frequency of the outer metal ring is f1, 3GHz < f1 < 10GHz; four resistors are loaded on the outer metal ring, and the four resistors are loaded at a center-symmetric position; the middle metal ring is a center-symmetric polygon, the shape of the middle metal ring is consistent with that of the outer metal ring and the centers are overlapped; the resonant frequency of the middle metal ring is f2, 3GHz < f2 < 10GHz; four resistors are loaded on the middle metal ring, and the four resistors are loaded at a center-symmetric position; the inner metal ring is a center-symmetric polygon, the shape of the inner metal ring is consistent with that of the outer metal ring and the centers are overlapped; the inner metal ring is recessed inward on the basis of 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 four resistors are loaded at a center-symmetric position.

3. The metasurface structure of claim 2, wherein, The absorbing layer metal layer is composed of three metal rings, and the three metal rings have the following relationships: the resonant frequencies of the three metal rings have the relationship f3 < f1 < f2; f2 is greater than the working frequency of the microstrip antenna, and the working frequency of the microstrip antenna is 2GHz; the three metal rings resonate at three different frequencies f1, f2 and f3 respectively.

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