Electromagnetic wave absorbing structure and parameter determination method

Abstract

The present disclosure proposes an electromagnetic wave absorbing structure and parameter determination method, which calculates the first thickness of the matching metamaterial according to the input admittance relationship and the preset conductivity of the matching metamaterial of the parameter to be determined; determines the target surface resistance and target period of the matching metamaterial according to the preset conductivity, the material characteristics of the matching metamaterial, and the equivalent conductivity tensor of the metamaterial to be matched; determines the admittance of the high dielectric film according to the input admittance relationship and the first thickness; determines the thickness dielectric constant relationship of the high dielectric film based on the admittance of the high dielectric film and the parameter admittance relationship of the high dielectric film; determines the target dielectric constant and the second thickness of the high dielectric film at the target frequency, the admittance of the high dielectric film and the thickness dielectric constant relationship. The method avoids the shortcomings of the traditional metamaterial method in the low-frequency band below 1 GHz, such as thickness sensitivity, narrow bandwidth, and reduced absorption efficiency, and reduces the absorption frequency without changing the thickness of the electromagnetic wave absorbing.

Description

Technical Field

[0001] The present disclosure relates to the technical field of electronic materials, and in particular to an electromagnetic wave absorbing structure and a method for determining parameters. Background Art

[0002] Electromagnetic wave absorbing materials are functional materials that reduce electronic interference of communication electronic equipment, reduce electromagnetic scattering signals of equipment, and improve electromagnetic stealth. Aircraft, drones, ships, vehicles, radars and other equipment are covered with electromagnetic wave absorbing materials to enhance stealth effects and reduce the risk of detection.

[0003] In practical applications, the application of traditional electromagnetic absorbing materials in low-frequency (longer wavelength) areas is limited due to their narrow absorption band and weak absorption capacity. To solve this problem, the relevant technology adopts increasing the thickness of electromagnetic absorbing materials to improve the absorbing effect. However, increasing the thickness leads to an increase in the volume and weight of the electromagnetic absorbing materials, which is not conducive to integration and loading during use. Summary of the invention

[0004] The present disclosure provides an electromagnetic wave absorbing structure and a parameter determination method.

[0005] The first aspect of the present disclosure provides a method for determining parameters of an electromagnetic wave absorbing structure, wherein the electromagnetic wave absorbing structure includes a metal plate, a matching metamaterial, and a high dielectric film, wherein the matching metamaterial is located between the metal plate and the high dielectric film, and the method includes:

[0006] Calculating a first thickness of the matching metamaterial according to an input admittance relationship of the matching metamaterial of the to-be-determined parameter and a preset conductivity;

[0007] Determining a target surface resistance and a target period of the matching metamaterial according to the preset conductivity, the material characteristics of the matching metamaterial, and the equivalent conductivity tensor of the metamaterial to be matched;

[0008] Determining the admittance of the high dielectric film according to the input admittance relationship and the first thickness;

[0009] Determining a thickness-dielectric constant relationship of the high dielectric film based on the admittance of the high dielectric film and a parameter-admittance relationship of the high dielectric film;

[0010] Based on the target frequency, the admittance of the high dielectric film and the thickness dielectric constant relationship, a target dielectric constant and a second thickness of the high dielectric film are determined; and the first thickness, the target surface resistance, the target period, the target dielectric constant and the second thickness are output.

[0011] In the embodiment of the present disclosure, the first thickness of the matching metamaterial is calculated according to the input admittance relationship of the matching metamaterial with the parameters to be determined and the preset conductivity, including:

[0012] Determine the conductivity thickness product corresponding to the matching metamaterial at the target frequency according to the input admittance relationship of the matching metamaterial of the parameter to be determined;

[0013] The first thickness of the matching metamaterial is calculated according to the preset conductivity and the conductivity-thickness product.

[0014] In the embodiment of the present disclosure, determining the target surface resistance and target period of the matching metamaterial according to the preset conductivity, the material characteristics of the matching metamaterial, and the equivalent conductivity tensor of the metamaterial to be matched includes:

[0015] Determining a periodic relationship of the surface resistance of the metamaterial to be matched according to the preset conductivity and the equivalent conductivity tensor of the metamaterial to be matched;

[0016] Selecting at least one set of first combination parameters of sheet resistance and period corresponding to the preset conductivity respectively;

[0017] Determining a target surface resistance of the matching metamaterial according to the material characteristics;

[0018] A target period corresponding to the target sheet resistance is selected from the first combination parameters.

[0019] In an embodiment of the present disclosure, determining the thickness dielectric constant relationship of the high dielectric film according to the input admittance relationship, the first thickness, and the parameter admittance relationship of the high dielectric film includes:

[0020] Determining the admittance of the high dielectric film according to the input admittance relationship and the first thickness;

[0021] Based on the admittance of the high dielectric film and the parameter-admittance relationship of the high dielectric film, the thickness-dielectric constant relationship of the high dielectric film is determined.

[0022] In the embodiment of the present disclosure, the input admittance relationship is: , the conductivity-thickness product ,

[0023] Wherein, ω is the angular frequency, Y1 is the input admittance of the metamaterial to be matched, σ is the conductivity of the metamaterial to be matched, d is the thickness of the metamaterial to be matched, ε0 is the vacuum dielectric constant, c is the speed of light, G0 is the space admittance, and σd is the conductivity-thickness product.

[0024] In the disclosed embodiment, the conductivity thickness product of the matching metamaterial is 8 millisiemens.

[0025] In the disclosed embodiment, the target period is 20 mm, the target surface resistance of the metamaterial to be matched is 125 ohm, the first thickness is 20 mm; the second thickness is 2 mm, and the target dielectric constant is 900 or 400 or 100.

[0026] The second aspect of the present disclosure provides an electromagnetic wave absorbing structure, which includes a metal plate, a matching metamaterial and a high dielectric film, wherein the matching metamaterial is located between the metal plate and the high dielectric film; the matching metamaterial includes a plurality of metamaterial units, and any metamaterial unit is composed of a conductive film unit;

[0027] The matching metamaterial is used to generate a target matching conductivity in a preset communication frequency band;

[0028] The high dielectric film is used to generate a target matching admittance in a preset communication frequency band, and the input admittance of the matching metamaterial and the high dielectric film is a spatial admittance.

[0029] In the disclosed embodiment, the metamaterial unit is in any of rectangular and cylindrical shapes.

[0030] In the disclosed embodiment, the metal plate is any one of the following: gold, silver, copper, iron, tin, and aluminum alloy.

[0031] The technical solution provided in the embodiments of the present disclosure has at least the following technical effects or advantages:

[0032] The electromagnetic wave absorbing structure in the parameter determination method of the electromagnetic wave absorbing structure in the embodiment of the present disclosure includes a metal plate, a matching metamaterial and a high dielectric film, wherein the matching metamaterial is located between the metal plate and the high dielectric film, and the method includes: calculating the first thickness of the matching metamaterial according to the input admittance relationship of the matching metamaterial whose parameters are to be determined and the preset conductivity; determining the target surface resistance and target period of the matching metamaterial according to the preset conductivity, the material characteristics of the matching metamaterial, and the equivalent conductivity tensor of the metamaterial to be matched; by determining the target surface resistance and target period of the matching metamaterial, its electromagnetic characteristics can be further regulated to improve the absorption capacity. This enables the electromagnetic wave absorbing structure to achieve a stronger electromagnetic absorption effect while maintaining lightness and thinness, solving the problem of weak absorption capacity of traditional materials. On this basis, the admittance of the high dielectric film is determined according to the input admittance relationship and the first thickness; the thickness dielectric constant relationship of the high dielectric film is determined based on the admittance of the high dielectric film and the parameter admittance relationship of the high dielectric film; the target dielectric constant and the second thickness of the high dielectric film are determined at the target frequency, the admittance of the high dielectric film and the thickness dielectric constant relationship; the first thickness, the target surface resistance, the target period, the target dielectric constant and the second thickness are output. By determining the thickness dielectric constant relationship of the high dielectric film, its electromagnetic properties can be adjusted to meet the needs of different application scenarios. This design flexibility enables the electromagnetic absorbing structure to achieve a wider range of applications while maintaining high performance. By calculating the target dielectric constant and the second thickness of the high dielectric film, the shortcomings of the traditional metamaterial method in the low-frequency band below 1 GHz, such as thickness sensitivity, narrow bandwidth and reduced absorption efficiency, are avoided, and efficient absorption is achieved, so that the electromagnetic absorbing structure can significantly reduce the absorption frequency without changing the thickness and almost not affecting the absorption efficiency performance.

[0033] Additional aspects and advantages of the present disclosure will be given in part in the following description and in part will be obvious from the following description or learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present disclosure. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0035] Figure 1 A schematic diagram of an electromagnetic wave absorbing structure provided by an embodiment of the present disclosure is shown;

[0036] Figure 2A schematic diagram of a conductivity matching metamaterial in an electromagnetic wave absorbing structure provided by an embodiment of the present disclosure is shown;

[0037] Figure 3 A flow chart showing a method for determining parameters of an electromagnetic wave absorbing structure provided by an embodiment of the present disclosure is shown;

[0038] Figure 4 A schematic diagram showing a method for determining parameters of an electromagnetic wave absorbing structure provided by another embodiment of the present disclosure is shown;

[0039] Figure 5 A schematic diagram showing a method for determining parameters of an electromagnetic wave absorbing structure provided by yet another embodiment of the present disclosure is shown;

[0040] Figure 6 A schematic diagram showing a method for determining parameters of an electromagnetic wave absorbing structure provided by another embodiment of the present disclosure is shown;

[0041] Figure 7 A schematic diagram of a method for determining parameters of an electromagnetic wave absorbing structure provided by another embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0042] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0043] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the present disclosure should have the common meanings understood by those skilled in the art to which the present disclosure belongs.

[0044] When electromagnetic waves encounter different media during propagation, they will reflect. If the impedance of the two media matches, the electromagnetic waves can be transmitted smoothly and the reflection will be reduced. Electromagnetic absorbing materials are functional materials that reduce electronic interference of communication electronic equipment, reduce electromagnetic scattering signals of equipment, and improve electromagnetic stealth. Aircraft, drones, ships, vehicles, radars and other equipment are covered with electromagnetic absorbing materials to enhance stealth effects and reduce the risk of detection. Antenna systems also often use absorbing materials to reduce electromagnetic interference between each other, reduce noise, and improve signal quality.

[0045] In practical applications, the application of traditional electromagnetic absorbing materials in low-frequency (longer wavelength) areas is limited due to their narrow absorption band and weak absorption capacity. To solve this problem, the relevant technology adopts increasing the thickness of electromagnetic absorbing materials to improve the absorbing effect. However, increasing the thickness leads to an increase in the volume and weight of the electromagnetic absorbing materials, which is not conducive to integration and loading during use.

[0046] In view of this, the embodiment of the present application proposes an electromagnetic wave absorbing structure to solve the problems existing in the prior art and improve the absorption of low-frequency signals without increasing the thickness. Figure 1 , an electromagnetic wave absorbing structure is disclosed in an embodiment of the present application, wherein the structure includes a metal plate 101, a matching metamaterial 102 and a high dielectric film 103, wherein the matching metamaterial is located between the metal plate and the high dielectric film; the matching metamaterial includes a plurality of metamaterial units, and any metamaterial unit is composed of a conductive film unit;

[0047] Matching metamaterials for generating target matching conductivity in a preset communication frequency band;

[0048] The high dielectric film is used to generate a target matching admittance in a preset communication frequency band, and the input admittance of the matching metamaterial and the high dielectric film is a spatial admittance.

[0049] Among them, the matched metamaterial is a conductivity-matched metamaterial, which is an artificial material that achieves a specific response to electromagnetic waves, especially in terms of conductivity, through its microstructure design. These metamaterials have electromagnetic properties that are not common in nature, and the propagation of electromagnetic waves through the material can be controlled by changing the structure of the material. The conductivity of the conductivity-matched metamaterial is designed so that its conductivity within a specific frequency range can match the conductivity of the surrounding medium or free space. This matching helps to reduce the reflection of electromagnetic waves and improve the transmission or absorption efficiency.

[0050] Conductivity-matched metamaterials are composed of periodic microscopic structural units, such as metal wires, rings, gaps, etc. By precisely designing the geometry, size, and arrangement of these structural units, a specific response to electromagnetic waves can be achieved.

[0051] Conductivity-matched metamaterials can operate within a specific frequency range, achieving effective manipulation of electromagnetic waves at specific frequencies. This frequency selectivity makes them very useful in communications, radar, and other applications that require specific frequency responses. By adjusting the conductivity and dielectric constant of the metamaterial, perfect absorption of electromagnetic waves can be achieved, making objects "invisible" to electromagnetic waves at specific frequencies. Conductivity-matched metamaterials can be used to manipulate the propagation direction of electromagnetic waves to achieve beam focusing, deflection, or shaping. They can be designed to absorb electromagnetic waves at specific frequencies for use in electromagnetic interference (EMI) shielding or absorbing materials.

[0052] Conductive films constitute the basic units (metamaterial units) of conductivity-matched metamaterials. These units achieve sparse current distribution in a preset direction through specific structural designs (such as conductive films with gaps interlaced to form a cross frame, rectangle, cylinder, etc.). The main function of conductivity-matched metamaterials is to achieve target matching conductivity in a preset communication frequency band to adjust the real part of the input admittance to match the air admittance and achieve effective absorption of electromagnetic waves. Figure 2 , which is a schematic diagram of a conductivity-matched metamaterial in an optional embodiment, wherein the conductivity-matched metamaterial includes 81 metamaterial units; the period of the metamaterial unit is p; the square resistance of the conductive film is Rs, and the thickness is tc; the thickness of the metamaterial unit is d. The number of metamaterial units can be increased or decreased, the period of the metamaterial unit is p can be increased or decreased, the thickness of the metamaterial unit is d can be increased or decreased, the square resistance of the conductive film is Rs can be increased or decreased, and the thickness of the conductive film is tc can be increased or decreased. The metamaterial unit is used to generate a preset current distribution in the x and y directions to reduce the conductivity of the metamaterial unit to a target threshold.

[0053] The high dielectric film has a high dielectric constant, which is used to adjust the imaginary part of the input admittance, and plays the role of taking the same value and opposite sign as the imaginary part of the input admittance of the conductivity matching metamaterial. The dielectric constant and thickness of the high dielectric film are determined by the thickness of the conductivity matching material, and are used to generate the target susceptance in a preset frequency band. In one embodiment, the thickness of the high dielectric film is td; the thickness of the metal substrate is tm; the thickness of the high dielectric film td should be less than the thickness d of the conductivity matching metamaterial; the thickness of the metal substrate tm should be greater than the skin depth of the electromagnetic wave at the operating frequency. The metal plate can be made of highly conductive materials such as gold, silver, copper, iron, tin, and aluminum alloy.

[0054] Synergistic effect: The conductive film and the high dielectric film work together to match the real part of the conductivity matching metamaterial with the imaginary part of the high dielectric film, so that the overall input admittance of the electromagnetic absorbing structure matches the admittance of air, thereby achieving perfect absorption of incident electromagnetic waves. This allows the electromagnetic absorbing structure to significantly reduce the absorption frequency without increasing the thickness and almost without affecting the absorption efficiency, thus achieving an ultra-thin, broadband absorbing structure in the frequency band below 1 GHz.

[0055] like Figure 3 As shown, the method for determining parameters of the electromagnetic wave absorbing structure of the embodiment of the present disclosure, wherein the electromagnetic wave absorbing structure is as follows Figure 1 Specifically, the method may include the following steps:

[0056] In step S31, a first thickness of the matching metamaterial is calculated according to an input admittance relationship of the matching metamaterial of the to-be-determined parameter and a preset conductivity.

[0057] For example, input admittance (Y) is a parameter that describes the ability of a metamaterial to match the impedance of free space at a specific frequency. The input admittance relationship is usually expressed in complex form, including real and imaginary parts, corresponding to conductance and susceptance, respectively. The default conductivity (σ) is an intrinsic property of the material that determines the material's ability to conduct electric current. In the calculation, the conductivity will be used to determine the electromagnetic properties of the material.

[0058] The input admittance relationship is expressed using transmission line theory as follows:

[0059]

[0060] Among them, G0 is the spatial admittance, σ is the conductivity of the metamaterial, ω is the angular frequency, ε0 ​​is the vacuum dielectric constant, c is the speed of light, d is the thickness of the metamaterial, and j is the sign of the imaginary number.

[0061] In the input admittance relationship, the thickness of the metamaterial is one of the parameters that need to be determined in the embodiment of the present disclosure. The conductivity of the metamaterial can be determined according to the actual application scenario, so the conductivity is assumed to be known in the embodiment of the present disclosure.

[0062] According to the input admittance relationship, the relationship between the metamaterial thickness and the input admittance is determined. Specifically, an equation can be solved to obtain the corresponding first thickness.

[0063] In an optional embodiment, in the case of low frequency, an approximate method can be used to simplify the calculation of the above input admittance relationship. Specifically, the above input admittance formula can be approximately simplified as follows:

[0064]

[0065] It can be seen from the above formula that when the conductivity thickness product σd is equal to a constant, the input admittance Y1 of the conductivity matching metamaterial can be approximately equal to the vacuum admittance (space admittance) G0 at low frequency; the value of this constant is:

[0066]

[0067] Therefore, the specific calculation process of the first thickness can be: according to the input admittance relationship of the matching metamaterial with the parameters to be determined, determine the conductivity thickness product corresponding to the matching metamaterial at the target frequency, wherein the conductivity thickness product is the conductivity thickness product required to achieve conductivity matching under low-frequency approximation; according to the preset conductivity and the conductivity thickness product, calculate the first thickness of the matching metamaterial.

[0068] After determining the thickness of the metamaterial, it is necessary to further determine other parameters of the metamaterial, such as the surface resistance of the conductive film unit that constitutes the metamaterial and the size (period) of the metamaterial unit.

[0069] In step S32, the target surface resistance and target period of the matching metamaterial are determined according to the preset conductivity, the material characteristics of the matching metamaterial, and the equivalent conductivity tensor of the metamaterial to be matched.

[0070] Exemplarily, first, it is necessary to determine the material properties of the matching metamaterial, including its chemical composition, microstructure, electromagnetic parameters (such as dielectric constant, magnetic permeability), etc. At the same time, it is necessary to clarify the influence of the preset conductivity on the electromagnetic properties of the material and how it interacts with the equivalent conductivity tensor of the matching metamaterial. Construct an equivalent circuit model of the matching metamaterial, which should be able to accurately reflect its electromagnetic properties. In the equivalent circuit model, sheet resistance and period can be introduced as two parameters of the circuit to describe the electromagnetic response of the material. Use optimization algorithms (such as genetic algorithms, particle swarm optimization, etc.) to adjust the values ​​of the parameters to maximize the matching metamaterial's absorption performance or impedance matching performance within a specific frequency range. During the optimization process, it is necessary to iterate the calculation continuously and adjust the value of the sheet resistance according to the calculation results until the predetermined performance target is achieved.

[0071] When determining the period, the equivalent conductivity tensor can be used to describe the electromagnetic response of the matching metamaterial at a specific frequency. Analyze the relationship between the components of the equivalent conductivity tensor and the periodic structural parameters, and how they affect the electromagnetic properties of the material. By adjusting the periodic structural parameters of the matching metamaterial (such as the size and shape changes of the unit structure), its electromagnetic properties can be optimized. During the optimization process, it is necessary to continuously iteratively calculate the equivalent conductivity tensor and adjust the periodic structural parameters based on the calculation results.

[0072] In an optional embodiment, the specific implementation process of determining the target surface resistance and the target period is: determining the surface resistance-period relationship of the metamaterial to be matched according to the preset conductivity and the equivalent conductivity tensor of the metamaterial to be matched; selecting at least one set of first combination parameters of the surface resistance and the period corresponding to the preset conductivity; determining the target surface resistance of the matching metamaterial according to the material characteristics; and screening the target period corresponding to the target surface resistance in the first combination parameters.

[0073] Exemplarily, the material characteristics of the matched metamaterial may be chemical composition microstructure, electromagnetic parameters (such as dielectric constant, magnetic permeability), etc. After determining these material characteristics, the equivalent conductivity tensor of the metamaterial may be constructed:

[0074]

[0075] The first, second, and third items on the diagonal represent the conductivity components in the x, y, and z directions, respectively, and σ s is the surface conductivity parameter of the conductive film; the surface conductivity parameter σ s is the reciprocal of the surface resistance Rs, σ s= 1 / Rs. The metamaterial structure requires that the thickness tc of the conductive film is much smaller than the period p and the thickness d.

[0076] The equivalent conductivity tensor is thus It is equal to the preset conductivity. When the surface conductivity parameters remain unchanged, the relationship between the period and the equivalent conductivity can be obtained.

[0077] It can be seen from the above embodiments that the material characteristics of the conductive film constituting the metamaterial determine the size of the sheet resistance, so the size of the sheet resistance corresponding to the metamaterial can be directly measured or obtained by other means. After determining the sheet resistance, the size of the period is further determined according to the above equivalent conductivity tensor.

[0078] In addition to the above implementation methods, the relationship between the period and the equivalent conductivity can also be obtained according to the formula of the equivalent conductivity tensor, such as Figure 4 The relationship between the period and the equivalent conductivity in the embodiment of the present disclosure is shown. The relationship corresponding to different surface conductances is different. Specifically, Figure 4 The solid line in the middle represents the equivalent conductivity value curve when the Rs value is 125 ohm; the circle line represents the equivalent conductivity value curve when the Rs value is 400 ohm.

[0079] Therefore, when the equivalent conductivity is known, multiple sets of combined parameters of period and surface conductance can be obtained; then the target period that meets the metamaterial material and the surface conductance corresponding to the target period can be determined as the final parameters based on the material characteristics.

[0080] like Figure 5 As shown in the figure, the parameters corresponding to the metamaterial are Rs = 125 ohm, p = 20 mm, d = 20 mm. The solid line represents the real part of the input admittance of the metamaterial, and the circle line represents the imaginary part of the input admittance of the metamaterial. The real part is approximately a constant value, which is approximately equal to G0; the imaginary part is less than zero, showing inductance characteristics, and the absolute value decreases with the increase of frequency.

[0081] Therefore, in order to further make the electromagnetic absorbing structure close to the spatial admittance, it is also necessary to use the conductive properties of the high dielectric film to offset the above Figure 5 The imaginary part of the admittance.

[0082] In step S33, the admittance of the high dielectric film is determined according to the input admittance relationship and the first thickness.

[0083] Exemplarily, in the above step S31, when the conductivity thickness product of the metamaterial is known and fixed, the imaginary part of the corresponding metamaterial is , in order to offset the imaginary part of the metamaterial, the corresponding admittance of the high dielectric film is .

[0084] In step S34, the thickness-dielectric constant relationship of the high dielectric film is determined based on the admittance of the high dielectric film and the parameter-admittance relationship of the high dielectric film.

[0085] Exemplarily, the parameter conductivity relationship of the high dielectric film can be:

[0086]

[0087] Where εd is the dielectric constant of the high dielectric film, k0 is the vacuum wave number (a known parameter), td is the film thickness, the angular frequency ω approaches zero, and the speed of light c and G0 spatial admittance are known.

[0088] Therefore, the dielectric constant of the high dielectric film can be adjusted by the thickness td and the dielectric constant εd to obtain the thickness-dielectric constant relationship.

[0089] In step S35, the target dielectric constant and the second thickness of the high dielectric film are determined based on the target frequency, the admittance of the high dielectric film, and the dielectric constant relationship between the thickness; and the first thickness, target surface resistance, target period, target dielectric constant, and second thickness are output.

[0090] For example, Figure 6 The value of the imaginary part of admittance corresponding to different dielectric constants at different frequencies is shown. The value of the imaginary part of admittance is a constant. At the same time, the target frequency is the frequency corresponding to the use environment of the electromagnetic absorbing structure. Therefore, according to Figure 6 The curve in uniquely determines the target dielectric constant corresponding to the high dielectric constant. After determining the target dielectric constant, the second thickness of the high dielectric constant is determined according to the above thickness-dielectric constant relationship.

[0091] Therefore, according to the above content, the parameters of the electromagnetic absorbing structure can be calculated, including the first thickness (the thickness of the metamaterial), the target surface resistance (the surface resistance of the conductive film in the metamaterial), the target period (the size of the metamaterial unit), the target dielectric constant (the dielectric constant of the high dielectric film) and the second thickness (the thickness of the high dielectric film).

[0092] The corresponding parameters are output to obtain a structure that meets the use requirements of the electromagnetic wave absorbing structure.

[0093] Next, the wave absorption rate corresponding to the electromagnetic wave absorption structure determined by the method for determining the parameters of the electromagnetic wave absorption structure of the present application is described with a specific example. Figure 7 As shown, in the conductivity matching metamaterial module, the metamaterial unit period p = 20 mm, the square resistance Rs of the conductive film (metamaterial) = 125 ohm, and the thickness d = 20 mm; the dielectric constant of the high dielectric film is 900, and the thickness is 2 mm; the performance of the electromagnetic absorbing structure is as follows Figure 7As shown in curve 1, the maximum absorption efficiency of 99.8% can be achieved at 250 MHz. In the conductivity matching metamaterial module, the metamaterial unit period p = 20 mm, the square resistance Rs of the conductive film = 125 ohm, and the thickness d = 20 mm; the dielectric constant of the high dielectric film is 400 and the thickness is 2 mm; the performance of the electromagnetic absorption structure is as follows Figure 7 As shown in curve 2, the maximum absorption efficiency of 99.6% can be achieved at 380 MHz. In the conductivity matching metamaterial module, the metamaterial unit period p = 20 mm, the square resistance Rs of the conductive film = 125 ohm, and the thickness d = 20 mm; the dielectric constant of the high dielectric film is 100 and the thickness is 2 mm; the performance of the electromagnetic absorption structure is as follows Figure 7 As shown in curve 3, the maximum absorption efficiency of 99.9% can be achieved at 750 MHz.

[0094] The electromagnetic wave absorbing structure in the parameter determination method of the electromagnetic wave absorbing structure provided in the embodiment of the present disclosure includes a metal plate, a matching metamaterial and a high dielectric film, and the matching metamaterial is located between the metal plate and the high dielectric film. The method includes: calculating the first thickness of the matching metamaterial according to the input admittance relationship of the matching metamaterial whose parameters are to be determined and the preset conductivity; determining the target surface resistance and target period of the matching metamaterial according to the preset conductivity, the material characteristics of the matching metamaterial, and the equivalent conductivity tensor of the metamaterial to be matched; by determining the target surface resistance and target period of the matching metamaterial, its electromagnetic characteristics can be further regulated to improve the absorption capacity. This enables the electromagnetic wave absorbing structure to achieve a stronger electromagnetic absorption effect while maintaining lightness and thinness, solving the problem of weak absorption capacity of traditional materials. On this basis, the admittance of the high dielectric film is determined according to the input admittance relationship and the first thickness; the thickness dielectric constant relationship of the high dielectric film is determined based on the admittance of the high dielectric film and the parameter admittance relationship of the high dielectric film; the target dielectric constant and the second thickness of the high dielectric film are determined at the target frequency, the admittance of the high dielectric film and the thickness dielectric constant relationship; the first thickness, target surface resistance, target period, target dielectric constant and second thickness are output. By determining the thickness dielectric constant relationship of the high dielectric film, its electromagnetic properties can be adjusted to meet the needs of different application scenarios. This design flexibility enables the electromagnetic absorbing structure to achieve a wider range of applications while maintaining high performance. By calculating the target dielectric constant and the second thickness of the high dielectric film, it can be ensured that the electromagnetic absorbing structure achieves the best absorbing effect at the target frequency. This method avoids the performance degradation problem caused by improper selection of thickness and dielectric constant in traditional materials, allowing the electromagnetic absorbing structure to achieve efficient absorbing at a specific frequency.

[0095] It should be noted that:

[0096] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present disclosure can be practiced without these specific details. In some instances, well-known structures and technologies are not shown in detail so as not to obscure the understanding of this description.

[0097] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various inventive aspects, in the above description of the exemplary embodiments of the present disclosure, the various features of the present disclosure are sometimes grouped together into a single embodiment, figure, or description thereof. However, the disclosed method should not be interpreted as reflecting the following schematic diagram: the claimed disclosure requires more features than the features explicitly recited in each claim. More specifically, as reflected in the claims below, the inventive aspects lie in less than all the features of the single embodiment disclosed above. Therefore, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, with each claim itself serving as a separate embodiment of the present disclosure.

[0098] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present disclosure and form different embodiments. For example, in the claims below, any one of the claimed embodiments may be used in any combination.

[0099] The above are only preferred specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A method for determining parameters of an electromagnetic wave absorbing structure, characterized in that: The electromagnetic wave absorbing structure comprises a metal plate, a matching metamaterial and a high dielectric film, wherein the matching metamaterial is located between the metal plate and the high dielectric film, and the method comprises: According to the input admittance relationship of the matching metamaterial of the to-be-determined parameter, the conductivity thickness product corresponding to the matching metamaterial at the target frequency is determined; the input admittance relationship is: , the conductivity-thickness product , Wherein, ω is the angular frequency, Y1 is the input admittance of the matching metamaterial, σ is the conductivity of the matching metamaterial, d is the thickness of the matching metamaterial, ε0 is the vacuum dielectric constant, c is the speed of light, G0 is the free space admittance, and σd is the conductivity-thickness product; Calculating a first thickness of the matching metamaterial according to a preset conductivity and the conductivity-thickness product; Determining a target surface resistance and a target period of the matching metamaterial according to a preset conductivity, a material characteristic of the matching metamaterial, and an equivalent conductivity tensor of the matching metamaterial; Determining the admittance of the high dielectric film according to the input admittance relationship and the first thickness; Determining a thickness-dielectric constant relationship of the high dielectric film based on the admittance of the high dielectric film and a parameter-admittance relationship of the high dielectric film; According to the target frequency, the admittance of the high dielectric film and the thickness-dielectric constant relationship, the target dielectric constant and the second thickness of the high dielectric film are determined; and the first thickness, the target surface resistance, the target period, the target dielectric constant and the second thickness are output.

2. The method according to claim 1, characterized in that Determining the target surface resistance and target period of the matching metamaterial according to the preset conductivity, the material characteristics of the matching metamaterial, and the equivalent conductivity tensor of the matching metamaterial includes: Determining a periodic relationship of the surface resistance of the matching metamaterial according to the preset conductivity and the equivalent conductivity tensor of the matching metamaterial; Selecting at least one set of first combination parameters of sheet resistance and period corresponding to the preset conductivity respectively; Determining a target surface resistance of the matching metamaterial according to the material characteristics; A target period corresponding to the target sheet resistance is selected from the first combination parameters.

3. The method according to claim 1, characterized in that The conductivity thickness product of the matched metamaterial is 8 millisiemens.

4. The method according to claim 1, characterized in that: The target period is 20 mm, the target surface resistance of the matching metamaterial is 125 ohm, the first thickness is 20 mm; the second thickness is 2 mm, and the target dielectric constant is 900, 400 or 100.

5. An electromagnetic wave absorbing structure, characterized in that: The structure includes a metal plate, a matching metamaterial and a high dielectric film, wherein the matching metamaterial is located between the metal plate and the high dielectric film; the matching metamaterial includes a plurality of metamaterial units, and any metamaterial unit is composed of a conductive film unit; The matching metamaterial is used to generate a target matching conductivity in a preset communication frequency band; The target matching conductivity is used to calculate the first thickness of the matching metamaterial by adding the conductivity thickness product; the conductivity thickness product is determined according to the input admittance relationship of the matching metamaterial; the input admittance relationship is: , the conductivity-thickness product , Wherein, ω is the angular frequency, Y1 is the input admittance of the matching metamaterial, σ is the conductivity of the matching metamaterial, d is the thickness of the matching metamaterial, ε0 is the vacuum dielectric constant, c is the speed of light, G0 is the free space admittance, and σd is the conductivity-thickness product; The high dielectric film is used to generate a target matching admittance in a preset communication frequency band, and the input admittance of the matching metamaterial and the high dielectric film is a free space admittance.

6. The structure according to claim 5, characterized in that The metamaterial unit is in any of a rectangular and cylindrical shape.

7. The structure according to claim 5, characterized in that The material of the metal plate is any one of the following: gold, silver, copper, iron, tin, and aluminum alloy.

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