Coded electromagnetic shielding superstructure optimization design system and method and superstructure unit array

Abstract

The invention discloses an electromagnetic shielding technical scheme of a coding superstructure and an optimization design system. The electromagnetic shielding technical scheme comprises a reflectivity setting module which sets a reflectivity threshold according to target shielding performance; the superstructure construction module generates an initial candidate array based on the symmetric unit design; and the parameter optimization module dynamically adjusts the sub-block thickness and the unit ratio k value through a particle swarm algorithm, and realizes 1-18GHz broadband reflectivity optimization in combination with a piecewise evaluation function. According to the invention, through deep fusion of coding superstructure design and an intelligent optimization system, collaborative optimization of electromagnetic loss and phase regulation is successfully realized, and significant technical advantages are formed in key indexes such as broadband absorption, angle adaptability, system efficiency and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic metamaterials, and specifically refers to an optimized design system, method and superstructure unit array of a coded electromagnetic shielding superstructure. Background Art

[0002] The current mainstream electromagnetic shielding technologies mainly include two solutions: metal shielding enclosures and traditional absorbing structures. Metal shielding enclosures reflect electromagnetic waves through metal materials (such as aluminum, copper, etc.) to achieve shielding, and are widely used in high-frequency electromagnetic radiation scenarios such as vehicle-mounted radars and GPS. Its technical principle relies on the high conductivity of the metal to reflect the incident electromagnetic waves to other directions, thereby reducing the electromagnetic interference between devices. Traditional absorbing structures use dielectric loss materials (such as carbon-based composite materials) to absorb the energy of electromagnetic waves and convert it into heat energy dissipation. Most existing absorbing materials achieve electromagnetic loss through uniform structure design (such as flat composite materials) or simple periodic arrangement. For example, the absorbing structure proposed in Patent CN112996374A improves the absorption efficiency through multi-layer impedance matching design. In addition, some technologies attempt to optimize the electromagnetic performance through the design of metamaterial units. For example, the absorbing material based on impedance metamaterials proposed in Patent CN110385903A designs a multi-layer impedance metamaterial structure, and uses the impedance gradient characteristics of each layer of material to reduce the reflection of electromagnetic waves on the material surface, while enhancing the multiple reflections and losses of electromagnetic waves inside the material, thereby achieving a wider frequency band of absorbing effect.

[0003] However, the metal shielding enclosure reflects the incident electromagnetic waves to random directions, resulting in the signal oscillating repeatedly inside the vehicle and exacerbating the complexity of the vehicle's electromagnetic environment. The electromagnetic loss characteristics of existing absorbing materials (such as flat composite materials) are limited by the resonance frequency, and can only achieve efficient absorption in a specific frequency band (such as 2 - 6 GHz), and cannot cover the entire 1 - 18 GHz frequency band. Under the condition of oblique incidence (θ > 45°), the impedance matching characteristics of the material deteriorate, resulting in a significant decrease in the absorption performance. The traditional metamaterial design relies on the trial-and-error method to adjust the unit parameters (such as thickness, shape), lacks automated optimization means, and is difficult to coordinate and control the absorption and phase characteristics. The absorbing material based on impedance metamaterials proposed in Patent CN110385903A improves the absorption performance through impedance metamaterials, but its design method relies on empirical parameter adjustment (such as manual optimization of layer thickness, material ratio, etc.) and lacks automated algorithm support.

[0004] Therefore, inventing an optimized design system of a coded electromagnetic shielding superstructure that can optimize the sub-block thickness and unit ratio, ensure meeting the target shielding index in the full frequency band, improve the robustness of broadband performance, and include automated algorithm-driven design to achieve the co-optimization of broadband electromagnetic shielding and signal directional regulation has become an urgent technical problem to be solved. Summary of the Invention

[0005] The object of the present invention is to provide a coded electromagnetic shielding superstructure optimization design system, method and superstructure unit array. The present invention can solve problems such as insufficient frequency band coverage, irregular scattering, angular sensitivity and polarization dependence, narrowband limitation, and difficulty in synergistically regulating absorption and phase characteristics due to low design efficiency, and realizes automatic search for the optimal solution through an automated algorithm-driven design and synergistic optimization of phase regulation and loss.

[0006] To achieve this object, a coded electromagnetic shielding superstructure optimization design system designed by the present invention includes:

[0007] A reflectivity setting module is used to set a target reflectivity according to the target electromagnetic shielding performance;

[0008] A superstructure construction module is used to construct a plurality of electromagnetic shielding sub-block units through electromagnetic simulation according to the principle of random generation of sub-block thicknesses, define the electromagnetic shielding sub-block units in the same frequency range as the same type of electromagnetic shielding sub-block units, and select a set number of electromagnetic shielding sub-block units in each type of electromagnetic shielding sub-block units to form an initial candidate array;

[0009] A parameter optimization module is used to update the thicknesses of the electromagnetic shielding sub-block units in the initial candidate array and the proportion of each type of electromagnetic shielding sub-block units in the initial candidate array by using a particle swarm optimization algorithm to obtain a first optimized unit array and complete the first optimization process; evaluate the deviation evaluation value between the reflectivity of the first optimized unit array and the target reflectivity through an evaluation function. When the deviation evaluation value does not reach the set value, update the thicknesses of the electromagnetic shielding sub-block units in the first optimized unit array and the proportion of each type of electromagnetic shielding sub-block units in the first optimized unit array by using a particle swarm optimization algorithm to obtain a second optimized unit array and complete the second optimization process; perform the Nth optimization process until the deviation evaluation value between the reflectivity of the Nth optimized unit array and the target reflectivity reaches the set value to obtain a superstructure unit array.

[0010] Preferably, before the parameter optimization module, it is necessary to evaluate the electromagnetic shielding sub-block units constructed by electromagnetic simulation technology to obtain the initial range of the structural parameters of the electromagnetic shielding sub-block units to ensure that the resonant frequency of the electromagnetic shielding sub-block units is within the working frequency band.

[0011] Preferably, the principle of random generation of sub-block thicknesses is that the thicknesses of each sub-block in each electromagnetic shielding sub-block unit are randomly selected within the set thickness range. The specific construction method of constructing the electromagnetic shielding sub-block unit through the sub-block matrix is: divide the electromagnetic shielding sub-block unit into several equal-sized parts, and copy the parameter variables of one part to the remaining parts until the entire electromagnetic shielding sub-block unit is filled.

[0012] Preferably, the electromagnetic shielding sub-block unit is set as a matrix containing 10×10 square sub-blocks. The four sub-blocks closest to the center point of the matrix are set to the standard height. Taking the center point of the sub-block matrix as the coordinate origin, a rectangular coordinate system is constructed parallel to the matrix boundary. Combining the diagonal of the sub-block matrix, the sub-block matrix is divided into eight parts. The part of the sub-block matrix divided by the diagonal in the first quadrant and the positive half-axis of the X-axis is the first part. The thickness of the sub-blocks in the first part is mirrored along the x-axis to the second part. The two parts are simultaneously rotated counterclockwise by 90° three times around the origin to fill the entire electromagnetic shielding sub-block unit.

[0013] Preferably, the particle swarm optimization algorithm is used to update the thickness of the electromagnetic shielding sub-block unit (1) and the specific method for updating the proportion of the electromagnetic shielding sub-block units (1) of different preset categories in the candidate array is as follows: An initial population containing a set number of individual particles is created according to the particle swarm algorithm. Each particle represents a set of parameter combinations of a set electromagnetic shielding sub-block unit (1). The thickness parameter combination of the electromagnetic shielding sub-block unit (1) consists of n thickness parameters and a proportion:

[0014] Particle = [h1, h2, h3, ……, h n-1 , h n , k]

[0015] Among them, h1 - h n represent the thickness variables of each of the 1 - n sub-blocks, k represents the proportion of the electromagnetic shielding sub-block unit (1) in the initial candidate array (2). Each parameter in the parameter combination is uniformly distributed within its allowable range. By updating the particle velocity and particle position, the thickness variables h1 - h n and the value of the proportion k are dynamically adjusted.

[0016] Preferably, the reflectivity is calculated based on the reflection amplitude, reflection phase of the electromagnetic shielding sub-block unit of the initial candidate array, and the proportion of different electromagnetic shielding sub-block units in the initial candidate array. The specific formula is:

[0017]

[0018] Among them, the subscripts "1" and "2" represent the electromagnetic shielding sub-block cells with different electromagnetic characteristics, that is, different categories of electromagnetic shielding sub-block units. a1 and a2 are the reflection amplitudes of the two types of electromagnetic shielding sub-block units respectively, and represent the reflection phase, k and (1 - k) are the proportions of the two types of units in the superstructure, RL is the reflectivity, e is a constant, and i is the imaginary part;

[0019] The specific calculation formula for obtaining the deviation evaluation value through the evaluation function is:

[0020]

[0021] Among them, cost is the value of the evaluation function, g and g0 respectively represent the judgment value and threshold of the reflectivity RL, m1, m2, and m3 respectively represent the reflectivity values required for three different set frequency bands, i1, i2, i3, and i4 respectively represent the first set electromagnetic wave frequency, the second set electromagnetic wave frequency, the third set electromagnetic wave frequency, and the fourth set electromagnetic wave frequency, f represents the electromagnetic wave frequency, dB represents decibel, GHz is the frequency unit representing gigahertz, dB·GHz represents the integral of the reflectivity in a specific frequency range with decibel dB as the unit, RE represents the reflection efficiency, quantified in decibel dB. The optimization goal is to find the minimum value of cost, update the particle velocity and particle position, and calculate the fitness value based on cost to evaluate each particle, guiding the search direction of the particle swarm optimization algorithm to ensure that the reflectivity can achieve the set technical indicators in a wide frequency range.

[0022] Advantages of the present invention:

[0023] The present invention proposes a coded electromagnetic shielding superstructure optimization design system, method and superstructure unit array. By optimizing the arrangement ratio and size parameters of the coded superstructure units through the particle swarm algorithm, a reflectivity index below -10 dB is achieved in the 1 - 18 GHz ultra-wide frequency band. The unique phase regulation mechanism (such as the nearly 180° phase difference design in the 7.4 - 18 GHz frequency band) enables the electromagnetic signal to be strongly absorbed and deflected to the specified area simultaneously, solving the problem of electromagnetic environment disorder caused by multi-directional scattering of traditional metal enclosures; adopting a symmetric electromagnetic shielding sub-block unit design (INS-1 mirror symmetry and INS-2 rotational symmetry instructions), the superstructure exhibits stable impedance matching characteristics in the TE / TM polarization waves and within the large incident angle range of 0° - 60°; the innovative design of the three-level linkage system of reflectivity setting, superstructure construction and parameter optimization dynamically adjusts the sub-block thickness variables h1 - h 14 and the unit occupancy ratio k value through the particle swarm algorithm, shortening the optimization period. By using a segmented evaluation function and setting different reflectivity thresholds m1 - m3 in the 1 - 4 GHz, 4 - 8 GHz, and 8 - 18 GHz frequency bands respectively, the accurate achievement of the technical indicators in the full frequency band is realized. Through the deep integration of the coded superstructure design and the intelligent optimization system, the collaborative optimization of electromagnetic loss and phase regulation is successfully achieved, forming significant technical advantages in key indicators such as broadband absorption, angle adaptability, and system efficiency. Description of the Drawings

[0024] Figure 1 is the structural schematic diagram of the present invention;

[0025] Figure 2 is the schematic diagram of the initial candidate array;

[0026] Figure 3It is a schematic diagram of the superstructure and a schematic diagram of the reflection phases of the electromagnetic shielding sub-block units CS1 and CS2 in the array;

[0027] Among them, Figure 3 (a) is a schematic diagram of the superstructure, Figure 3 (b) is the reflection phases of the electromagnetic shielding sub-block units CS1 and CS2 in the array;

[0028] Figure 4 It is a schematic diagram of the unit structure design;

[0029] Among them, Figure 4 (a) and Figure 4 (b) are the 1 / 4 matrices of CS1 and CS2 respectively, Figure 4 (c) is a comparison diagram of the real part of the impedance of CS1 and CS2 with the flat composite material, Figure 4 (d) is a comparison diagram of the imaginary part of the impedance of CS1 and CS2 with the flat composite material, Figure 4 (e) is a comparison diagram of the equivalent dielectric constant of CS1 and CS2 with the flat composite material, Figure 4 (f) is a comparison diagram of the reflectivity of CS1 and CS2 with the flat composite material;

[0030] Figure 5 It is a schematic diagram of the reflectivity of the electromagnetic shielding sub-block units CS1 and CS2 at incident angles from 0° to 60°;

[0031] Among them, Figure 5 (a) and Figure 5 (b) are the schematic diagrams of the TE polarization of CS1 and the TM polarization of CS1 respectively, Figure 5 (c) and Figure 5 (d) are the schematic diagrams of the TE polarization of CS2 and the TM polarization of CS2 respectively;

[0032] Figure 6 It is the far-field pattern of the superstructure;

[0033] Among them, Figure 6 (a), Figure 6 (b) and Figure 6 (c) are the three-dimensional far-field patterns at 2 GHz, 8 GHz, and 18 GHz respectively, Figure 6 (d), Figure 6 (e) and Figure 6 (f) are the one-dimensional far-field patterns at 2 GHz, 8 GHz, and 18 GHz respectively;

[0034] Figure 7 It is a schematic diagram of the reflectivity of the superstructure under different incident angle conditions;

[0035] Among them, Figure 7 (a) is the TE polarization reflectivity of the superstructure under different incident angle conditions,Figure 7 (b) TM polarization reflectivity of the superstructure under different incident angles;

[0036] Figure 8 It is a decomposition diagram of the unit structure;

[0037] In the figure, 1 - electromagnetic shielding sub-block unit, 2 - initial candidate array, 3 - superstructure unit array, 4 - matrix periodic unit. Specific implementation manners

[0038] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0039] The following further elaborates the present invention in detail in conjunction with the accompanying drawings and specific embodiments:

[0040] Embodiment 1

[0041] An optimized design system for a coded electromagnetic shielding superstructure, as Figure 1 shown, it includes:

[0042] The reflectivity setting module is used to set the target reflectivity according to the target electromagnetic shielding performance;

[0043] The superstructure construction module is used to construct multiple electromagnetic shielding sub-block units 1 through electromagnetic simulation according to the principle of random generation of sub-block thicknesses, as Figure 8 , define the electromagnetic shielding sub-block units 1 in the same frequency range as the same type of electromagnetic shielding sub-block units 1, and select a set number of electromagnetic shielding sub-block units 1 from each type of electromagnetic shielding sub-block units 1 to form an initial candidate array 2, as Figure 2 ;

[0044] The parameter optimization module is used to evaluate the deviation evaluation value between the reflectivity of the initial candidate array 2 and the target reflectivity through an evaluation function, and use the particle swarm optimization algorithm to update the thickness of the electromagnetic shielding sub-block unit 1 in the initial candidate array 2 and the proportion of each type of electromagnetic shielding sub-block unit 1 in the initial candidate array 2 to obtain the first optimized unit array and complete the first optimization process; evaluate the deviation evaluation value between the reflectivity of the first optimized unit array and the target reflectivity through the evaluation function. When this deviation evaluation value does not reach the set value, use the particle swarm optimization algorithm to update the thickness of the electromagnetic shielding sub-block unit 1 in the first optimized unit array and the proportion of each type of electromagnetic shielding sub-block unit 1 in the first optimized unit array to obtain the second optimized unit array and complete the second optimization process; perform the Nth optimization process until the deviation evaluation value between the reflectivity of the Nth optimized unit array and the target reflectivity reaches the set value. The Nth optimized unit array is the superstructure unit array 3, such as Figure 3 。

[0045] In the above technical solution, a set number of electromagnetic shielding sub-block units 1 are selected from one type of electromagnetic shielding sub-block unit CS1 and another type of electromagnetic shielding sub-block unit CS2 to form the initial candidate array 2, and CS1 and CS2 need to be selected to form the initial candidate array 2 according to the principle of complementary frequency band performance.

[0046] In the above technical solution, the electromagnetic shielding sub-block unit 1 is the basic component unit that constitutes the electromagnetic shielding superstructure. It is like small blocks for building blocks. Multiple electromagnetic shielding sub-block units 1 are combined and arranged to form a superstructure, which usually has specific shapes, sizes and electromagnetic characteristics. For example, in this embodiment, it is in the form of a matrix containing 10×10 square sub-blocks. Through the optimization design of its parameters (such as sub-block thickness, etc.), the electromagnetic unit can absorb and reflect electromagnetic waves, etc., so as to achieve the electromagnetic shielding function.

[0047] In the above technical solution, "simulation" refers to the process of numerically calculating and analyzing the structure and performance of electromagnetic units through computer simulation technology. It is a method for predicting and optimizing the electromagnetic characteristics (such as reflectivity, impedance matching, etc.) of electromagnetic units in a virtual environment. Specifically, the role of simulation in the design of electromagnetic units includes: simulating electromagnetic behavior, optimizing design parameters and verifying design schemes. For example, the document mentions "simulating S parameters and calculating the real and imaginary parts of the impedance of CS1 and CS2". Here, "simulation" is to use simulation technology to obtain the relevant electromagnetic characteristic parameters of the electromagnetic unit, and then evaluate its performance.

[0048] In the above technical solution, before the parameter optimization module, it is necessary to evaluate the electromagnetic shielding sub-block unit 1 constructed by electromagnetic simulation technology to obtain the initial range of the structural parameters of the electromagnetic shielding sub-block unit 1 to ensure that the resonance frequency of the electromagnetic shielding sub-block unit 1 is within the working frequency band.

[0049] In the above technical solution, through the key design constraint of evaluating the initial range of structural parameters, the effectiveness of the optimization algorithm is ensured, the feasibility of the technical solution is strengthened, and the divergence of the algorithm caused by searching for invalid parameters is avoided; it reflects the core control of the matching between the resonant frequency and the operating frequency band, highlighting the technical rigor.

[0050] In the above technical solution, the principle of randomly generating the thickness of sub-blocks is that the thickness of each sub-block in each electromagnetic shielding sub-block unit 1 is randomly selected within the set thickness range;

[0051] The specific construction method of constructing the electromagnetic shielding sub-block unit 1 through the sub-block matrix is as follows: multiple sub-block matrices are constructed into a matrix period unit 4, and the matrix period unit 4 is periodically copied along the center point of the set electromagnetic shielding sub-block unit 1 to obtain an r×s sub-block matrix, which is the electromagnetic shielding sub-block unit 1.

[0052] In the above technical solution, the electromagnetic shielding sub-block unit 1 is constructed through the feature of the fast modeling method of mirror copying and rotational filling of partial parameters, ensuring structural diversity while reducing the computational complexity.

[0053] In the above technical solution, the electromagnetic shielding sub-block unit 1 is set as a square sub-block matrix, and the four square sub-blocks at the center point of the square sub-block matrix are set as the standard side length. Taking the center point of the square sub-block matrix as the coordinate origin, a rectangular coordinate system is constructed. The x-axis of this rectangular coordinate system is parallel to one side of the square sub-block matrix, and the y-axis is parallel to the adjacent other side of the square sub-block matrix. The rectangular coordinate system and the two diagonals of the square sub-block matrix divide the square sub-block matrix into eight parts. The part of the square sub-block matrix divided by the diagonal in the first quadrant of the rectangular coordinate system and the positive half-axis of the x-axis is the first part. The thickness parameter of the sub-blocks in the first part is mirrored along the x-axis to the second part. The thickness parameters of the sub-blocks in the two parts are simultaneously rotated 90° clockwise or counterclockwise three times around the origin, and the corresponding thickness parameters are filled each time until the thickness parameters are filled into the entire electromagnetic shielding sub-block unit 1.

[0054] In the above technical solution, the electromagnetic shielding sub-block unit 1 is as Figure 8 shown. The electromagnetic shielding sub-block unit 1 is set as a matrix containing 10×10 square sub-blocks. The four sub-blocks in the middle position are set as the standard height, and the thickness h0 = 30mm, h1 - h 14(Unit: mm) represents the thickness variable of the sub-block. To achieve polarization-insensitive radiation absorption characteristics, a symmetric design method is adopted: mirror the parameter variables of the first part (Part-1) in the figure along the x-axis to the second part (Part-2), and this process is called Instruction 1 (INS-1); then, rotate these two parts counterclockwise by 90° three times around the origin to fill the entire electromagnetic shielding sub-block unit 1, and this process is called Instruction 2 (INS-2). The length of the sub-block is set to p = 1.5 mm, and the length of the unit is set to p0 = 15 mm. The unit structure is designed through simulation and algorithm optimization.

[0055] In the above technical solution, the center point of the square sub-block matrix is used as the coordinate origin, which is the center point of the set electromagnetic shielding sub-block unit (1).

[0056] In the above technical solution, through the cooperation of the INS-1 mirror symmetry and INS-2 rotation symmetry instructions, strict geometric constraints are constructed to ensure the consistency of TE / TM polarization wave processing from the physical level and support the verification results of subsequent experiments.

[0057] In the above technical solution, the specific method of using the particle swarm optimization algorithm to update the thickness of the electromagnetic shielding sub-block unit 1 and the proportion of different preset types of electromagnetic shielding sub-block units 1 in the candidate array is as follows:

[0058] Create an initial population containing 20 individual particles according to the particle swarm algorithm. Each particle represents a set of parameter combinations of the electromagnetic shielding sub-block unit 1. The parameter combination of the electromagnetic shielding sub-block unit 1 consists of 15 parameters:

[0059] Particle = [h1, h2, h3, h4, h5, h6, h7, h8, h9, h 10 , h 11 , h 12 , h 13 , h 14 , k]

[0060] Among them, h1 - h 14 represent the thickness variables of 1 - n sub-blocks respectively, k represents the proportion of the electromagnetic shielding sub-block unit 1 in the initial candidate array 2. Each parameter in the parameter combination is uniformly distributed within its allowable range. By updating the particle velocity and particle position, the thickness variables h1 - h 14 and the value of the proportion k are dynamically adjusted. The same process is cyclically executed during the optimization process to find the required result.

[0061] In the above technical solution, through the parameter dimension definition (h1 - h 14Thickness variable and ratio k) Lock the key design variables. The segmented integral evaluation function (1 - 4 GHz / 4 - 8 GHz / 8 - 18 GHz) embodies the idea of band - differentiated optimization and supports broadband performance.

[0062] In the above - mentioned technical solution, the reflectivity is calculated according to the reflection amplitude, reflection phase of the electromagnetic shielding sub - block unit 1 of the initial candidate array 2, and the ratio of different electromagnetic shielding sub - block units 1 in the initial candidate array 2. The specific formula is:

[0063]

[0064] Among them, the subscripts "1" and "2" represent the cells of the electromagnetic shielding sub - block unit 1 with different electromagnetic characteristics, that is, different types of electromagnetic shielding sub - block units 1. a1 and a2 are the reflection amplitudes of the two types of electromagnetic shielding sub - block units 1 respectively. and represent the reflection phase, k and (1 - k) are the ratios of the two types of units in the superstructure, RL is the reflectivity, e is a constant, and i is the imaginary part;

[0065] The specific formula for obtaining the deviation evaluation value through the evaluation function is:

[0066]

[0067] Among them, cost is the value of the evaluation function, g and g0 respectively represent the judgment value and threshold of the reflectivity RL, m1, m2, m3 respectively represent the reflectivity values required for three different frequency bands set in the formula. The three different frequency bands set refer to the value range of f, dB represents decibel, GHz is the frequency unit representing gigahertz, dB·GHz represents the integral of the reflectivity in a specific frequency range with decibel dB as the unit, RE represents the reflection efficiency, quantified in decibel dB, f represents the electromagnetic wave frequency. The optimization goal is to find the minimum value of cost, update the particle velocity and particle position, and calculate the fitness value based on cost to evaluate each particle, guiding the search direction of the particle swarm optimization algorithm to ensure that the reflectivity can achieve the set technical indicators in the broadband range.

[0068] In the above - mentioned technical solution, by means of the segmented integral evaluation function and setting the reflectivity threshold, aiming at the problem that the high - frequency electromagnetic radiation effect is more obvious, a more stringent threshold is set to support the optimization requirements of the high - frequency band.

[0069] In the above - mentioned technical solution, it also includes an electromagnetic shielding sub - block unit 1 verification module, which selects CS1 and CS2 in the superstructure according to the set required reflectivity and compares them with the flat composite material;

[0070] Calculate the input impedance of the electromagnetic shielding sub - block unit 1, such as Figure 4 (a) andFigure 4 (b) shows the 1 / 4 matrix of CS1 and CS2. The squares represent the sub-blocks of the unit, and the numbers in them represent the thickness. The input impedance Z of the electromagnetic shielding sub-block unit 1 in The specific calculation formula is:

[0071]

[0072] where S 11 is the reflection coefficient of the electromagnetic shielding sub-block unit 1, and S 21 is the transmission coefficient of the electromagnetic shielding sub-block unit 1;

[0073] Simulate the S parameters, calculate the real and imaginary parts of the impedance of CS1 and CS2. As shown in Figure 4 (c) and Figure 4 (d), that is, the real and imaginary parts of the normalized input impedance. Compare the calculation results with the existing flat dielectric materials. The real part of the impedance of CS1 and CS2 is closer to 1, and the imaginary part is closer to 0. Therefore, the impedance matching characteristics are better in the entire 2 - 18 GHz frequency band; in the 1 - 2 GHz frequency band, the equivalent impedance of the unit deviates from the normalized position, but compared with the flat composite material, it still has better impedance matching characteristics;

[0074] Further discuss the difference in dielectric properties between CS1 and CS2 and the flat composite material. According to the transmission line theory and impedance matching principle, calculate the relationship between the input impedance and the equivalent electromagnetic parameters, and judge the loss ability of the electromagnetic shielding sub-block unit 1. The specific calculation formula is:

[0075]

[0076] where Z0 is the characteristic impedance of free space, f is the frequency of electromagnetic radiation, h eff is the thickness of the composite structure material, c is the speed of light in free space, ε eff and μ eff are the equivalent dielectric constant and permeability respectively, tanh is the hyperbolic tangent function, and i is the imaginary part;

[0077] It is known that CS1 and CS2 are dielectric loss materials. The real and imaginary parts of the equivalent permeability are μ eff ' = 1 and μ eff ” = 0. Simulate and calculate the real part ε eff ' and imaginary part ε eff ” of the equivalent dielectric constant and the loss tangent tanδ of CS1 and CS2, as shown in Figure 4 (e); compared with the flat composite material, the equivalent dielectric constant of the composite structure unit is reduced as a whole, and the dielectric loss is enhanced, indicating that it has better loss ability. Subsequently, simulate the reflectivity of CS1 and CS2 as shown in Figure 4As shown in Fig. (f), compared with the flat composite material of the same thickness, CS1 and CS2 have broadband and efficient radiation absorption performance;

[0078] Finally, by setting different oblique incidence angles, the absorption performance of CS1 and CS2 at different incident angles is tested. Let θ be the oblique incidence angle. The simulation results of CS1 are as Figure 5 (a) and Figure 5 (b) show that when the incident angle is as high as 60°, the reflectivity can still be maintained below -5 dB in the frequency band of 2 - 18 GHz; the simulation results of CS2 are as Figure 5 (c) and Figure 5 (d) show that when the incident angle reaches 45°, the reflectivity can still be maintained below -5 dB in the frequency band of 2 - 18 GHz. Generally speaking, although the impedance mismatch of the unit during oblique incidence leads to a decrease in the loss ability, the overall polarization insensitivity and wide-angle radiation absorption characteristics can still be maintained.

[0079] In the above technical solution, it further includes a superstructure evaluation module for evaluating the electromagnetic performance of the superstructure composed of different electromagnetic shielding sub-block units 1 to ensure that it meets the requirements of electromagnetic shielding. The specific method is as follows:

[0080] A superstructure is composed of CS1 and CS2. As Figure 3 (a) shows, the units are combined in a random arrangement. "1" and "2" represent CS1 and CS2 respectively. The electromagnetic shielding sub-block units 1 are combined in a random arrangement. q×q electromagnetic shielding sub-block units 1 are set as a super unit to reduce the in-plane coupling and meet the periodic boundary conditions of the simulation. The area of the superstructure is 300×300 mm 2 ; Calculate the reflection phases of CS1 and CS2, and construct a curve of frequency and reflection phase. As Figure 3 (b) shows, in the frequency band of 1 - 1.5 GHz, the phase difference satisfies 94° ≤ |Δφ| ≤ 108.9°. The performance is optimized through the synergistic effect of low loss and electromagnetic deflection; in the frequency band of 1.5 - 7.4 GHz, the unit itself has good absorption characteristics, and the phase difference satisfies The performance is optimized through the synergistic effect of high loss and electromagnetic deflection; in the frequency band of 7.4 - 18.0 GHz, the phase differences of the two units satisfy The phase difference is close to 180°, which can achieve more effective electromagnetic deflection. The performance of this frequency band is further optimized through the synergistic effect of high loss and efficient deflection;

[0081] Simulate the three-dimensional far-field radiation patterns at different frequencies to analyze the role of phase regulation in the design of the superstructure. Compare the phase differences between CS1 and CS2 at different frequencies. Based on the phase cancellation between electromagnetic shielding sub-block units 1, the reflected electromagnetic signals are deflected to a concentrated area. Then, simulate the one-dimensional far-field radiation pattern of the superstructure, and compare the radar cross-sections at different planar scattering angles to obtain the low-reflection characteristics of the superstructure at different frequencies, which are used to evaluate the electromagnetic shielding effect.

[0082] In the above technical solution, corresponding optimizations are carried out according to the phase differences at different frequency bands, so as to achieve more effective electromagnetic deflection. This design method avoids the problem of the complexity of the vehicle's electromagnetic environment caused by the transmission and oscillation of multi-directional signals in space through the concentrated deflection of electromagnetic radiation, and further improves the electromagnetic shielding performance.

[0083] In the above technical solution, the specific method for simulating the three-dimensional far-field radiation patterns at different frequencies to evaluate the electromagnetic shielding effect is as follows: Simulate the three-dimensional far-field radiation patterns at the frequencies of 2 GHz, 10 GHz, and 18 GHz. As Figure 6 (a) - (c) shown, since the phase difference between CS1 and CS2 at 2 GHz is small, there is only a small amount of electromagnetic deflection, and compared with the unit structure, the performance of the superstructure is slightly improved. At the same time, since there are stable phase differences between CS1 and CS2 at the frequencies of 10 GHz and 18 GHz, which are 193.3° and 178.5° respectively, based on the phase cancellation between units, the reflected electromagnetic signals are deflected to a concentrated area. Subsequently, the one-dimensional far-field radiation pattern of the superstructure is simulated, as Figure 6 (d) - (f) shown, the radar cross-sections (RCS) in all reflection directions in the xoz plane and the yoz plane are significantly reduced, and part of the electromagnetic radiation is absorbed by the superstructure itself. Compared with the 2 GHz radiation pattern, the superstructure shows better low-reflection characteristics at 10 GHz and 18 GHz, which is caused by the additional electromagnetic deflection effect.

[0084] In the above technical solution, further analyze the relationship between the radiation absorption characteristics of the superstructure and the signal incident angle, as Figure 7 shown. The simulation results under TE polarization wave and TM polarization wave incidence are basically the same. Under the condition of normal incidence, the calculated results are in good agreement with the simulation results. The reflectivity in the frequency band of 1 - 2 GHz gradually decreases with the increase of the incident angle. In the frequency band of 2 - 18 GHz, the working bandwidth of the reflectivity below -10 dB is basically unchanged, but the performance gradually decreases with the increase of the incident angle from 0° to 45° at high frequencies. When the incident angle reaches 45°, the array can still maintain a reflectivity below -5 dB in the frequency band of 1 - 18 GHz. Obviously, the designed superstructure is not sensitive to the polarization angle and can achieve low-reflection characteristics in a large incident angle range. This conclusion shows that it has excellent polarization-insensitive and wide-angle radiation absorption characteristics.

[0085] In the above technical solution, this technology verifies the synergistic gain of phase regulation and intrinsic loss in the design of superstructures, and is expected to be applied to the field of broadband and high-frequency electromagnetic shielding technology that will become increasingly prominent in the future.

[0086] In the above technical solution, the present invention optimizes the arrangement ratio and size parameters of the coded superstructure unit through the particle swarm optimization algorithm, and realizes a reflectivity index of less than -10 dB in the ultra-wide frequency band of 1 - 18 GHz. The unique phase regulation mechanism (such as the design of a nearly 180° phase difference in the frequency band of 7.4 - 18 GHz) enables electromagnetic signals to be directionally deflected to a specified area while being strongly absorbed, solving the problem of electromagnetic environment disorder caused by multi-directional scattering of traditional metal covers; experiments show that the optimized superstructure can still maintain a reflectivity of less than -5 dB under the condition of oblique incidence of 45°, and compared with traditional flat composite materials, the effective electromagnetic absorption angle is extended from 0° to 45°, and the absorption efficiency is increased from 70% to more than 99.9%.

[0087] In the above technical solution, a symmetric electromagnetic shielding sub-block unit 1 design (INS-1 mirror symmetry and INS-2 rotational symmetry instructions) is adopted, so that the superstructure exhibits stable impedance matching characteristics in the TE / TM polarization wave and the large incident angle range of 0° - 60°, as Figure 4 (c) and Figure 4 (d) shown, the real part value of the normalized input impedance of the CS1 and CS2 units is close to 1, and the imaginary part value approaches 0. Compared with the conventional material, the real part impedance value is optimized from 5 to 1, and the imaginary part impedance value is optimized from 2 to 0, fundamentally breaking through the limitation that traditional wave absorbers are sensitive to the incident angle.

[0088] Example 2

[0089] An optimized method for a coded electromagnetic shielding superstructure, which includes the following steps:

[0090] Set the target reflectivity according to the target electromagnetic shielding performance;

[0091] Construct multiple electromagnetic shielding sub-block units 1 through electromagnetic simulation according to the random generation principle of the sub-block thickness, define the electromagnetic shielding sub-block units 1 in the same frequency range as the same type of electromagnetic shielding sub-block units 1, and select a set number of electromagnetic shielding sub-block units 1 in each type of electromagnetic shielding sub-block units 1 to form an initial candidate array 2;

[0092] Evaluate the deviation evaluation value between the reflectivity of the initial candidate array 2 and the target reflectivity through an evaluation function; use the particle swarm optimization algorithm to update the thickness of the electromagnetic shielding sub-block units 1 in the initial candidate array 2 and the proportion of each type of electromagnetic shielding sub-block unit 1 in the initial candidate array 2 to obtain the first optimized unit array and complete the first optimization process; evaluate the deviation evaluation value between the reflectivity of the first optimized unit array and the target reflectivity through the evaluation function, use the particle swarm optimization algorithm to update the thickness of the electromagnetic shielding sub-block units 1 in the first optimized unit array and the proportion of each type of electromagnetic shielding sub-block unit 1 in the first optimized unit array to obtain the second optimized unit array and complete the second optimization process; continue the Nth optimization process until the deviation evaluation value between the reflectivity of the Nth optimized unit array and the target reflectivity reaches the minimum value to obtain the superstructure unit array 3.

[0093] Embodiment 3

[0094] An encoded electromagnetic shielding superstructure unit array, and the encoded electromagnetic shielding superstructure unit array 3 is constructed by the method described in Embodiment 2.

[0095] Embodiment 4

[0096] A computer program product includes a computer program, and when the computer program is executed by a processor, the steps of the method described in Embodiment 3 are implemented.

[0097] The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

[0098] Those skilled in the art should understand that the embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0099] The present invention is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, and the combination of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processors of general-purpose computers, special-purpose computers, embedded processors, or other programmable data processing devices to generate a machine, so that the instructions executed by the processors of the computer or other programmable data processing devices generate for implementing in the process Figure 1 one process or multiple processes and / or blocksFigure 1 a system of functions specified in one or more boxes

[0100] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufactured article including an instruction system that implements the functions specified in one or more processes and / or boxes Figure 1 one or more processes and / or boxes Figure 1 a system of functions specified in one or more boxes

[0101] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operational steps are performed on the computer or other programmable device to produce a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes and / or boxes Figure 1 one or more processes and / or boxes Figure 1 a system of functions specified in one or more boxes

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the scope of its protection. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent replacements to the specific implementation manners of the invention, but these changes, modifications or equivalent replacements are all within the scope of the claims of the invention pending approval

Claims

1. An optimized design system for a coded electromagnetic shielding superstructure, characterized in that, Including: A reflectivity setting module is used to set a target reflectivity according to the target electromagnetic shielding performance; A superstructure construction module is used to construct a plurality of electromagnetic shielding sub-block units (1) through electromagnetic simulation according to the principle of random generation of sub-block thicknesses, define the electromagnetic shielding sub-block units (1) in the same frequency range as the same type of electromagnetic shielding sub-block units (1), and select a set number of electromagnetic shielding sub-block units (1) in each type of electromagnetic shielding sub-block units (1) to form an initial candidate array (2); A parameter optimization module is used to update the thickness of the electromagnetic shielding sub-block units (1) in the initial candidate array (2) and the proportion of each type of electromagnetic shielding sub-block units (1) in the initial candidate array (2) by using a particle swarm optimization algorithm to obtain a first optimized unit array and complete the first optimization process; evaluate the deviation evaluation value between the reflectivity of the first optimized unit array and the target reflectivity through an evaluation function. When the deviation evaluation value does not reach the set value, use the particle swarm optimization algorithm to update the thickness of the electromagnetic shielding sub-block units (1) in the first optimized unit array and the proportion of each type of electromagnetic shielding sub-block units (1) in the first optimized unit array to obtain a second optimized unit array and complete the second optimization process; perform the Nth optimization process until the deviation evaluation value between the reflectivity of the Nth optimized unit array and the target reflectivity reaches the set value to obtain a superstructure unit array (3).

2. The optimized design system of a coded electromagnetic shielding superstructure according to claim 1, characterized in that: Before the parameter optimization module, it is necessary to evaluate the electromagnetic shielding sub-block units (1) constructed by electromagnetic simulation technology to obtain the initial range of the structural parameters of the electromagnetic shielding sub-block units (1) and ensure that the resonant frequency of the electromagnetic shielding sub-block units (1) is within the working frequency band.

3. The optimized design system of a coded electromagnetic shielding superstructure according to claim 1, wherein: The principle of random generation of sub-block thicknesses is that the thicknesses of each sub-block in each electromagnetic shielding sub-block unit (1) are randomly selected within the set thickness range; The specific construction method of constructing the electromagnetic shielding sub-block units (1) through the sub-block matrix is: constructing a plurality of sub-block matrices into a matrix periodic unit (4), and periodically replicating the matrix periodic unit (4) along the center point of the set electromagnetic shielding sub-block unit (1) to obtain an r×s sub-block matrix, which is the electromagnetic shielding sub-block unit (1), where r is the number of rows of the sub-block matrix and s is the number of columns of the sub-block matrix.

4. An optimized design system for a coded electromagnetic shielding superstructure according to claim 1 or 3, characterized in that: The electromagnetic shielding sub-block unit (1) is set as a square sub-block matrix. The four square sub-blocks at the center point of the square sub-block matrix are set as the standard side length. Taking the center point of the square sub-block matrix as the coordinate origin, a rectangular coordinate system is constructed. The x-axis of this rectangular coordinate system is parallel to one side of the square sub-block matrix, and the y-axis is parallel to the adjacent other side of the square sub-block matrix. The rectangular coordinate system combined with the two diagonals of the square sub-block matrix divides the square sub-block matrix into eight parts. Among them, the part of the square sub-block matrix divided by the diagonal in the first quadrant of the rectangular coordinate system and the positive half-axis of the x-axis is the first part. The thickness parameter of the sub-blocks in the first part is mirrored along the x-axis to the second part. The thickness parameters of the sub-blocks in the two parts are simultaneously rotated 90° clockwise or counterclockwise three times around the origin, and the corresponding thickness parameters are filled each time until the thickness parameters are filled in the entire electromagnetic shielding sub-block unit (1).

5. The optimized design system of a coded electromagnetic shielding superstructure according to claim 1, characterized in that: The specific method for updating the thickness of the electromagnetic shielding sub-block unit (1) and the proportion of different preset types of electromagnetic shielding sub-block units (1) in the candidate array by using the particle swarm optimization algorithm is as follows: According to the particle swarm algorithm, an initial population containing a set number of individual particles is created. Each particle represents a set of parameter combinations of an electromagnetic shielding sub-block unit (1). The thickness parameter combination of the electromagnetic shielding sub-block unit (1) consists of n thickness parameters and a proportion: Particle = [h1, h2, h3, ……, h n-1 , h n , k] Among them, h1 - h n represents the thickness variables of each of the 1 - n sub - blocks, k represents the proportion of the electromagnetic shielding sub - block unit (1) in the initial candidate array (2), each parameter in the parameter combination is uniformly distributed within its allowable range, and by updating the particle velocity and particle position, the thickness variables h1 - h n and the value of the proportion k are dynamically adjusted.

6. The encoding electromagnetic shielding superstructure optimization design system according to claim 1, characterized in that: The reflectivity is calculated according to the reflection amplitude, reflection phase of the electromagnetic shielding sub-block unit (1) in the initial candidate array (2) and the proportion of different electromagnetic shielding sub-block units (1) in the initial candidate array (2). The specific formula is: Among them, the subscripts "1" and "2" represent the grid of electromagnetic shielding sub-block units (1) with different electromagnetic characteristics, that is, different categories of electromagnetic shielding sub-block units. a1 and a2 are the reflection amplitudes of the two types of electromagnetic shielding sub-block units (1) respectively, and represent the reflection phase. k and (1 - k) are the proportions of the two types of units in the superstructure. RL is the reflectivity, e is a constant, and i is the imaginary part; The specific calculation formula for obtaining the deviation evaluation value through the evaluation function is: Among them, cost is the value of the evaluation function, g and g0 respectively represent the judgment value and threshold of the reflectivity RL, m1, m2, and m3 respectively represent the reflectivity values required for three different set frequency bands, i1, i2, i3, and i4 respectively represent the first set electromagnetic wave frequency, the second set electromagnetic wave frequency, the third set electromagnetic wave frequency, and the fourth set electromagnetic wave frequency, f represents the electromagnetic wave frequency, dB represents decibel, GHz is the frequency unit representing gigahertz, dB·GHz represents the integral of the reflectivity in a specific frequency range with decibel dB as the unit, RE represents the reflection efficiency, quantified in decibel dB. The optimization goal is to find the minimum value of cost, update the particle velocity and particle position, and calculate the fitness value based on cost to evaluate each particle, guiding the search direction of the particle swarm optimization algorithm to ensure that the reflectivity can achieve the set technical indicators in a wide frequency range.

7. An optimized design system for a coded electromagnetic shielding superstructure according to claim 1, characterized in that: It also includes an electromagnetic shielding sub-block unit (1) verification module, which selects m different types of electromagnetic shielding sub-block units (1) in the superstructure according to the set required reflectivity and compares them with the flat composite material; Calculate the input impedance of the electromagnetic shielding sub-block unit (1), where the input impedance Z of the electromagnetic shielding sub-block unit (1) in The specific calculation formula is as follows: Among them, S 11 is the reflection coefficient of the electromagnetic shielding sub-block unit (1), and S 21 is the transmission coefficient of the electromagnetic shielding sub-block unit (1); Simulate the S-parameters, calculate the real and imaginary parts of the impedance of m different types of electromagnetic shielding sub-block units (1), that is, the real and imaginary parts of the normalized input impedance, and compare the calculation results with existing flat dielectric materials; According to the transmission line theory and impedance matching principle, calculate the relationship between the input impedance and the equivalent electromagnetic parameters, and judge the loss ability of the electromagnetic shielding sub-block unit (1). The specific calculation formula is: where, Z0 is the characteristic impedance of free space, f is the frequency of electromagnetic radiation, h eff is the thickness of the composite structural material, c is the speed of light in free space, ε eff and μ eff are the equivalent permittivity and permeability respectively, tanh is the hyperbolic tangent function, and i is the imaginary part; Finally, by setting different oblique incidence angles, test the absorption performance of m different types of electromagnetic shielding sub-block units (1) at different incidence angles.

8. The optimized design system of a coded electromagnetic shielding superstructure according to claim 1, characterized in that: It also includes a superstructure evaluation module for evaluating the electromagnetic performance of the superstructure composed of different electromagnetic shielding sub-block units (1) to ensure that it meets the requirements of electromagnetic shielding. The specific method is as follows: A superstructure is composed of q different types of electromagnetic shielding sub-block units (1). The electromagnetic shielding sub-block units (1) are combined in a random arrangement. A q×q electromagnetic shielding sub-block unit (1) is set as a super unit. Calculate the reflection phase of q different types of electromagnetic shielding sub-block units (1), construct a curve of frequency and reflection phase, and perform corresponding optimizations according to the phase differences in different frequency bands to achieve more effective electromagnetic deflection; Simulate the three-dimensional far-field pattern at different frequency points to analyze the role of phase control in the superstructure design. Compare the phase differences of q different types of electromagnetic shielding sub-block units (1) at different frequency points. Based on the phase cancellation between the electromagnetic shielding sub-block units (1), the reflected electromagnetic signals are deflected to a concentrated area; then simulate the one-dimensional far-field pattern of the superstructure, compare the radar cross-sections at different plane scattering angles, and obtain the low-reflection characteristics of the superstructure at different frequency points to evaluate the electromagnetic shielding effect.

9. A method for optimizing a coded electromagnetic shielding superstructure, characterized in that, The steps are as follows: Set the target reflectivity according to the target electromagnetic shielding performance; Construct multiple electromagnetic shielding sub-block units (1) through electromagnetic simulation according to the random generation principle of the sub-block thickness. Define the electromagnetic shielding sub-block units (1) in the same frequency range as the same type of electromagnetic shielding sub-block unit (1). Select a set number of electromagnetic shielding sub-block units (1) from each type of electromagnetic shielding sub-block unit (1) to form an initial candidate array (2); Evaluate the deviation evaluation value between the reflectivity of the initial candidate array (2) and the target reflectivity through an evaluation function; use the particle swarm optimization algorithm to update the thickness of the electromagnetic shielding sub-block units (1) in the initial candidate array (2) and the proportion of each type of electromagnetic shielding sub-block unit (1) in the initial candidate array (2) to obtain the first optimized unit array and complete the first optimization process; evaluate the deviation evaluation value between the reflectivity of the first optimized unit array and the target reflectivity through the evaluation function, and use the particle swarm optimization algorithm to update the thickness of the electromagnetic shielding sub-block units (1) in the first optimized unit array and the proportion of each type of electromagnetic shielding sub-block unit (1) in the first optimized unit array to obtain the second optimized unit array and complete the second optimization process; Continue the Nth optimization process until the deviation evaluation value between the reflectivity of the Nth optimized unit array and the target reflectivity reaches the minimum value to obtain the superstructure unit array (3).

10. A coded electromagnetic shielding superstructure unit array, characterized in that: The array (3) of the coded electromagnetic shielding superstructure units is constructed by the method described in claim 9.

11. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, the steps of the method described in claim 9 are implemented.

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