A wave-absorbing resistance film, a dual-polarized wave-absorbing superstructure and a preparation method

Abstract

The application discloses a wave-absorbing resistance film, a dual-polarized wave-absorbing superstructure and a preparation method, belongs to the technical field of microwave electromagnetic stealth, and aims at solving the problems of complex shape and numerous parameters for adjusting electromagnetic wave-absorbing performance of the snowflake-shaped wave-absorbing resistance film in the prior art. The wave-absorbing resistance film comprises a square ring and a fractal layer arranged in the ring-in area of the square ring; the fractal layer is a mesh structure composed of sin function curves and cos function curves, and the pattern of the fractal layer is symmetrical relative to the center point of the fractal layer. The application can be used for electromagnetic wave absorption.

Description

Technical Field

[0001] This invention belongs to the field of microwave electromagnetic stealth technology, and particularly relates to an absorbing resistive film, a dual-polarized absorbing superstructure, and its preparation method. Background Technology

[0002] In the field of electromagnetic wave absorption, with the widespread use and intensive application of electronic devices, electromagnetic interference (EMI) problems are becoming increasingly prominent, making the demand for high-efficiency electromagnetic wave absorbing materials extremely urgent. Snowflake-shaped absorbing resistive films exhibit significant advantages in electromagnetic wave absorption. Their complex and dense fractal structure can act like a delicate electromagnetic trap, reflecting and scattering incident electromagnetic waves multiple times.

[0003] However, due to the complex shape of the snowflake-shaped absorbing resistor film, there are many parameters to consider when adjusting the electromagnetic absorption performance (e.g., bandwidth) during the design process, which is quite difficult. Summary of the Invention

[0004] Based on the above analysis, the present invention aims to provide a microwave absorbing resistive film, a dual-polarized microwave absorbing superstructure, and a preparation method thereof, in order to solve the problems of the complex shape of snowflake-shaped microwave absorbing resistive films and the large number of parameters to be considered in the adjustment of electromagnetic absorption performance in the prior art.

[0005] The objective of this invention is mainly achieved through the following technical solutions.

[0006] This invention provides a microwave absorbing resistive film, comprising a square ring and a fractal layer disposed in a region within the square ring;

[0007] The fractal layer is a mesh structure composed of sine and cosine function curves, and the pattern of the fractal layer is symmetrical with respect to the center point of the fractal layer.

[0008] Furthermore, the transverse and longitudinal center lines of the fractal layer divide the fractal layer into four regions, which are, in a clockwise direction, the first region corresponding to the first quadrant, the second region corresponding to the second quadrant, the third region corresponding to the third quadrant, and the fourth region corresponding to the fourth quadrant.

[0009] Furthermore, both the first and third regions include multiple horizontal sine function curves and multiple vertical cosine function curves.

[0010] Furthermore, both the second and fourth regions include multiple horizontal cosine function curves and multiple vertical sinine function curves.

[0011] Furthermore, in the fractal layer, the inner width of the square ring is 5-6 mm, and the outer width is 11-13 mm.

[0012] The present invention also provides a dual-polarized absorbing superstructure, comprising a square ring fractal absorbing resistive film, wherein the square ring fractal absorbing resistive film is an absorbing resistive film.

[0013] Furthermore, it also includes a first dielectric substrate, a first air dielectric layer, a second dielectric substrate, a fractal absorbing resistive film, a second air dielectric layer, and a base plate, which are stacked sequentially from top to bottom.

[0014] Furthermore, the pattern of the fractal absorbing resistive film is symmetrical with respect to the center point of the fractal absorbing resistive film.

[0015] Furthermore, the pattern shape of the fractal layer is exactly the same as that of the fractal absorbing resistive film, with a size ratio of 2-3:5-6.

[0016] This invention also provides a method for fabricating a dual-polarized absorbing superstructure, which is used to fabricate the aforementioned dual-polarized absorbing superstructure. The fabrication method includes the following steps:

[0017] Provide a base plate;

[0018] A second air dielectric layer, a square ring fractal absorbing resistive film, a second dielectric plate, a first air dielectric layer, a fractal absorbing resistive film, and a first dielectric plate are sequentially formed on the base plate to obtain a dual-polarized absorbing superstructure.

[0019] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0020] A) The absorbing resistive film provided by this invention combines a square ring structure and a fractal structure on the same layer of absorbing resistive film. It uses sin function curves and cos function curves to form a complex patterned mesh structure. Since the sin function and cos function have multiple parameter variables such as A, ω and T, by changing the parameters and designing reasonably, it is possible to form a variety of regular shapes of absorbing resistive film patterns, thereby achieving different absorbing effects.

[0021] B) The absorbing resistive film provided by the present invention, in the same area, because multiple sin function curves are arranged in parallel with equal spacing and multiple cos function curves are arranged in parallel with equal spacing, the pattern formed is uniformly and symmetrically arranged from the center to the edge, which can ensure the electromagnetic absorption uniformity of the absorbing resistive film as a whole.

[0022] C) The dual-polarized absorbing superstructure provided by this invention can guarantee the absorption bandwidth and absorption rate in both polarization directions, and can be used for dual-polarized electromagnetic interference suppression in the full frequency band of 2-18GHz. Among them, the square ring fractal absorbing resistor film has a square structure and a fractal structure, and the fractal absorbing resistor film has a fractal structure, so that the square ring fractal absorbing resistor film and the fractal absorbing resistor film have self-similarity and exhibit resonant characteristics in multiple frequency bands, which can achieve effective absorption. At the same time, the square ring fractal absorbing resistor film and the fractal absorbing resistor film with different sheet resistance are used, and each layer is optimized for different frequency bands. When electromagnetic waves are incident on the dual-polarized absorbing superstructure, multiple electromagnetic wave reflections will be achieved in the two layers of absorbing resistor films with different sheet resistances, so that the absorption effects of each layer are superimposed. This not only matches the free space impedance to produce an ultra-wideband high absorption effect and improves the absorption effect, but also effectively reduces the thickness of the dual-polarized absorbing superstructure, making it more practical.

[0023] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained through the embodiments described and the accompanying drawings, which are particularly pointed out. Attached Figure Description

[0024] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0025] Figure 1 This is a schematic diagram of the structure of the microwave absorbing resistive film provided in the first aspect of the present invention;

[0026] Figure 2 A schematic diagram of the dual-polarized absorbing superstructure provided in the second aspect of the present invention;

[0027] Figure 3 This is a longitudinal cross-sectional view of the dual-polarized absorbing superstructure provided in the second aspect of the present invention;

[0028] Figure 4 A schematic diagram of the fractal absorbing resistive film in the dual-polarized absorbing superstructure provided in the second aspect of the present invention;

[0029] Figure 5 The figure shows the simulation function curve of the dual-polarization reflection coefficient of the dual-polarization absorbing superstructure in Embodiment 1 of the present invention, where TE refers to transverse polarization and TM refers to longitudinal polarization.

[0030] Figure label:

[0031] 1-First dielectric substrate; 2-Fractal absorbing resistive film; 3-First air dielectric layer; 4-Second dielectric substrate; 5-Square ring fractal absorbing resistive film; 51-Square ring; 52-Fractal layer; 6-Second air dielectric layer; 7-Base plate. Detailed Implementation

[0032] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0033] In a first aspect, the present invention provides a microwave absorbing resistive film, see [link to relevant documentation]. Figure 1 It includes a square ring 51 and a fractal layer 52 disposed in the region within the square ring 51. The fractal layer 52 is a mesh structure composed of sin function curves and cos function curves. The pattern of the fractal layer 52 is symmetrical with respect to the center point of the fractal layer 52.

[0034] Specifically, the horizontal and vertical center lines of the fractal layer 52 divide the fractal layer 52 into four regions, which are the first region corresponding to the first quadrant, the second region corresponding to the second quadrant, the third region corresponding to the third quadrant, and the fourth region corresponding to the fourth quadrant in a clockwise direction. The first and third regions have the same structure, both including multiple horizontal sin function curves and multiple vertical cos function curves. The second and fourth regions have the same structure, both including multiple horizontal cos function curves and multiple vertical sin function curves.

[0035] It should be noted that the complex patterns described above can be formed by combining sin or cos function curves through geometric transformations such as rotation, translation, and mirroring.

[0036] Compared with the prior art, the absorbing resistive film provided by the present invention combines a square ring structure and a fractal structure on the same layer of absorbing resistive film. It uses sin function curves and cos function curves to form a complex patterned mesh structure. Since the sin function and cos function have multiple parameter variables such as A, ω and T, by changing the parameters and designing reasonably, it is possible to form a variety of regular shapes of absorbing resistive film patterns, thereby achieving different absorbing effects.

[0037] Furthermore, within the same region, the parallel arrangement and equal spacing between multiple sine function curves and the parallel arrangement and equal spacing between multiple cosine function curves result in a uniform and symmetrical pattern from the center to the edge, ensuring the overall electromagnetic absorption uniformity of the absorbing resistive film.

[0038] Based on research, considering the wave absorption effect, the inner width of the square ring 51 in the above-mentioned fractal layer 52 is 5-6 mm, and the outer width is 11-13 mm.

[0039] Horizontal sine curve and vertical sine curve x=A x ×sin(ω x ×t x +φ x ),

[0040] A x =0.25~0.30, ω x =0.35~0.40π, φ x =0,t x =3~3.25, the horizontal cosine function curve and the vertical cosine function curve y=A y ×cos(ω y ×t y +φ y A y =0.25~0.30, ω y =0.35~0.40π, φ y =0,t y =3 to 3.25.

[0041] Secondly, this invention provides a dual-polarized absorbing superstructure, see [link to relevant documentation]. Figures 2 to 3 It includes a square ring fractal absorbing resistive film 5, which is the absorbing resistive film provided in the first aspect.

[0042] Compared with the prior art, the beneficial effects of the dual-polarized absorbing superstructure provided by the present invention are basically the same as those of the absorbing resistive film provided in the first aspect, and will not be elaborated here.

[0043] It is understood that the above-mentioned dual-polarized absorbing superstructure also includes a first dielectric plate 1, a fractal absorbing resistive film 2, a first air dielectric layer 3, a second dielectric plate 4, a second air dielectric layer 6, and a base plate 7, which are stacked sequentially from top to bottom.

[0044] Among them, the sheet resistance of the square ring fractal absorbing resistive film 5 is different from that of the fractal absorbing resistive film 2.

[0045] In order to better adjust the bandwidth and enhance the absorption effect, for example, the sheet resistance of the square ring fractal absorbing resistor film 5 is 50Ω / sq to 55Ω / sq (e.g., 50Ω / sq), and the sheet resistance of the fractal absorbing resistor film 2 is 380Ω / sq to 400Ω / sq.

[0046] Compared with existing technologies, the dual-polarized absorbing superstructure provided by this invention can guarantee the absorption bandwidth and absorption rate in both polarization directions, and can be used for dual-polarized electromagnetic interference suppression in the full frequency band of 2-18 GHz. Among them, the square ring fractal absorbing resistor film 5 has a square structure and a fractal structure, and the fractal absorbing resistor film 2 has a fractal structure, so that the square ring fractal absorbing resistor film 5 and the fractal absorbing resistor film 2 have self-similarity and exhibit resonant characteristics in multiple frequency bands, which can achieve effective absorption. At the same time, by using square ring fractal absorbing resistor film 5 and fractal absorbing resistor film 2 with different sheet resistances, each layer is optimized for different frequency bands. When electromagnetic waves are incident on the dual-polarized absorbing superstructure, multiple electromagnetic wave reflections will be achieved in the two layers of absorbing resistor films with different sheet resistances, so that the absorption effects of each layer are superimposed. This not only matches the free space impedance to produce an ultra-wideband high absorption effect and improves the absorption effect, but also effectively reduces the thickness of the dual-polarized absorbing superstructure, making it more practical.

[0047] For the pattern of the fractal absorbing resistive film 2, exemplarily, the pattern of the fractal absorbing resistive film 2 is symmetrical with respect to the center point of the fractal absorbing resistive film 2.

[0048] Specifically, the transverse and longitudinal center lines of the fractal absorbing resistive film 2 divide it into four regions, which, in a clockwise direction, are the fourth region corresponding to the first quadrant, the fifth region corresponding to the second quadrant, the sixth region corresponding to the third quadrant, and the seventh region corresponding to the fourth quadrant. The fourth and sixth regions have the same structure, both including multiple transverse sine function curves and multiple longitudinal cosine function curves. The fifth and seventh regions have the same structure, both including multiple transverse cosine function curves and multiple longitudinal sine function curves. See [link to relevant documentation]. Figure 4 .

[0049] After research, considering the absorption effect, in the above-mentioned fractal absorbing resistive film 2, the transverse sin function curve and the longitudinal sin function curve x=A x ×sin(ω x ×t x +φ x A x =0.55~0.60, ω x =0.35~0.40π, φ x =0,t x =6.0~6.5, the horizontal cosine function curve and the vertical cosine function curve y=A y ×cos(ω y ×t y +φ y A y =0.55~0.60, ω y =0.35~0.40π, φ y=0,t y =6.0~6.5.

[0050] In order to further control the wave absorption effect, for example, the pattern shape of the fractal layer 52 is exactly the same as the pattern shape of the fractal wave absorbing resistor film 2, and the size ratio is 2-3:5-6. That is to say, the pattern of the fractal layer 52 can be obtained by enlarging the pattern of the fractal layer 52 in a ratio of 2-3:5-6.

[0051] Considering that the microwave absorption performance of existing metal-based materials, ferrite materials, and carbon-based materials decreases with increasing temperature and cannot achieve stable and efficient microwave absorption performance, in order to improve the high-temperature resistance of the above-mentioned dual-polarized microwave absorbing superstructure, for example, the base plate 7 is a carbon fiber plate for reflecting electromagnetic waves; the first dielectric plate 1 and the second dielectric plate 4 are glass fiber epoxy resin plates; the square ring fractal microwave absorbing resistor film 5 and the fractal microwave absorbing resistor film 2 are high-temperature resistant resistor films, such as graphene films or ruthenium-based resistor films.

[0052] In this way, all the above layers are made of high-temperature resistant materials, which greatly improves the high-temperature resistance of the dual-polarized absorbing superstructure, maintains stable energy dissipation and oxidation resistance, and achieves high-performance absorption at high temperatures. In addition, since the materials used in the above layers are lightweight and thin, the overall thickness and weight of the dual-polarized absorbing superstructure can be further reduced while ensuring broadband absorption effect and high absorption rate.

[0053] It should be noted that the above-mentioned dual-polarized absorbing superstructure has the characteristics of high mechanical hardness and good chemical stability, which can ensure stable performance and longer service life under long-term and high-temperature environments.

[0054] Considering the thickness of each layer, in order to further adjust the bandwidth and absorption rate, the shape of the above-mentioned dual-polarized absorbing superstructure is a square with a side length of 15-20 mm. The base plate 7 is a carbon fiber plate with a thickness of 0.4-0.5 mm. The relative permittivity of the first dielectric plate 1 and the second dielectric plate 4 is 4-5, the thickness of the first dielectric plate 1 and the second dielectric plate 4 is 0.4-0.6 mm, and the thickness of the first air dielectric layer 3 and the second air dielectric layer 6 is 2.0-2.5 mm.

[0055] In order to form the first air dielectric layer 3 and the second air dielectric layer 6, the above-mentioned dual-polarized absorbing superstructure also includes a first support column and a second support column. The first support column is disposed between the first dielectric plate 1 and the second dielectric plate 4, so that a gap is formed between the first dielectric plate 1 and the second dielectric plate 4, which serves as the first air dielectric layer 3. The second support column is disposed between the second dielectric plate 4 and the bottom plate 7, so that a gap is formed between the second dielectric plate 4 and the bottom plate 7, which serves as the second air dielectric layer 6.

[0056] In order to improve the connection stability between the above layers, the dual-polarized absorbing superstructure also includes an adhesive layer. The first dielectric plate 1 and the first support column, the first support column and the second dielectric plate 4, the second dielectric plate 4 and the second support column, and the second support column and the base plate 7 are all connected by an adhesive layer (e.g., POE film), so that the dual-polarized absorbing superstructure forms an integral structure.

[0057] The aforementioned dual-polarized absorbing superstructure also includes a first carrier layer and a second carrier layer. A square ring fractal absorbing resistive film 5 is formed on the first carrier layer, and a fractal absorbing resistive film 2 is formed on the second carrier layer. The square ring fractal absorbing resistive film 5 is disposed between the first carrier layer and the first dielectric plate 1, and the fractal absorbing resistive film 2 is formed on the second carrier layer. The fractal absorbing resistive film 2 is disposed between the second carrier layer and the second dielectric plate 4.

[0058] To further improve the absorption performance of the aforementioned dual-polarized absorbing superstructure, the surface of the square ring fractal absorbing resistive film 5 facing the first carrier layer is textured, and the surface of the fractal absorbing resistive film 2 facing the second carrier layer is also textured. By textured surfaces of the square ring fractal absorbing resistive film 5 and the fractal absorbing resistive film 2, the surface roughness of both is effectively increased, allowing electromagnetic waves to be reflected more effectively, thus further enhancing the absorption effect.

[0059] Thirdly, the present invention provides a method for fabricating a dual-polarized absorbing superstructure, used for fabricating the dual-polarized absorbing superstructure provided in the second aspect, the method comprising the following steps:

[0060] Provide a base plate 7;

[0061] A second air dielectric layer 6, a square ring fractal absorbing resistive film 5, a second dielectric plate 4, a first air dielectric layer 3, a fractal absorbing resistive film 2, and a first dielectric plate 1 are sequentially formed on the base plate 7 to obtain a dual-polarized absorbing superstructure.

[0062] Compared with the prior art, the beneficial effects of the preparation method of the dual-polarized absorbing superstructure provided by the present invention are basically the same as those of the dual-polarized absorbing superstructure provided in the second aspect, and will not be elaborated here.

[0063] For example, the above-mentioned square ring fractal absorbing resistive film 5 can be formed in the following manner:

[0064] The square ring fractal absorbing resistive film 5 relies on the first carrier layer, and the specific preparation method includes the following steps:

[0065] Provide a rigid template with a textured surface;

[0066] A raw material solution (e.g., polyethylene solution or polyimide solution) is coated onto a rigid template to form the first support layer, and the first support layer is obtained after the solvent evaporates.

[0067] The first load-bearing layer is peeled off from the rigid template to form a first load-bearing layer with a textured structure;

[0068] Flip the first carrier layer so that the textured surface faces upward;

[0069] According to the pattern of the square ring fractal absorbing resistive film 5, conductive paste is coated on the textured surface of the first carrier layer to form the square ring fractal absorbing resistive film 5.

[0070] In this way, the above preparation method uses a rigid template as the template for the first carrier layer, transfers the texture structure from the rigid template to the first carrier layer, and then transfers the texture structure to the square ring fractal absorbing resistive film 5 by coating with conductive paste, thereby achieving efficient and high-precision preparation of the square ring fractal absorbing resistive film 5.

[0071] Accordingly, the fractal absorbing resistive film 2 described above can be formed in the following manner:

[0072] The fractal absorbing resistive film 2 relies on the second carrier layer, and the specific preparation method includes the following steps:

[0073] Provide a rigid template with a textured surface;

[0074] A raw material solution (e.g., polyethylene solution or polyimide solution) is coated onto a rigid template to form a second support layer, and the solvent is evaporated to obtain the second support layer.

[0075] The second load-bearing layer is peeled off from the rigid template to form a second load-bearing layer with a textured structure;

[0076] Flip the second carrier layer so that the textured surface faces upward;

[0077] According to the pattern of the fractal absorbing resistive film 2, conductive paste is coated on the textured surface of the second carrier layer to form the fractal absorbing resistive film 2.

[0078] In this way, the above preparation method uses a rigid template as the template for the second carrier layer, transfers the texture structure from the rigid template to the second carrier layer, and then transfers the texture structure to the fractal absorbing resistive film 2 by coating with conductive paste, thereby achieving efficient and high-precision preparation of the fractal absorbing resistive film 2.

[0079] Example 1

[0080] This embodiment provides a dual-polarized absorbing superstructure, comprising a first dielectric plate, a fractal absorbing resistive film, a first air dielectric layer, a second dielectric plate, a square ring fractal absorbing resistive film, a second air dielectric layer, and a base plate stacked sequentially.

[0081] The side length of the dual-polarized absorbing superstructure is 15 mm.

[0082] In the fractal absorbing resistive film, the period of the structural unit is L = 15 mm, and the transverse sin function curve and the longitudinal sin function curve are x = A. x ×sin(ω x ×t x +φ x A x =0.60, ω x =0.40π, φ x =0,t x =6.5, the horizontal cosine function curve and the vertical cosine function curve y=A y ×cos(ω y ×t y +φ y ),

[0083] A y =0.60, ω y =0.40π, φ y =0,t y =6.5, sheet resistance is 50Ω / sq.

[0084] In the square ring fractal absorbing resistor film, the outer width of the square ring is 13mm and the inner width is 5mm. The transverse sin function curve and the longitudinal sin function curve x=A x ×sin(ω x ×t x +φ x A x =0.30, ω x =0.40π, φ x =0,t x =3.25, the horizontal cosine function curve and the vertical cosine function curve y=A y ×cos(ω y ×t y +φ y A y =0.30, ω y =0.40π, φ y =0,t y =3.25, sheet resistance is 400Ω / sq.

[0085] Both the first and second dielectric substrates are made of glass fiber epoxy resin boards with a relative permittivity of 4.4 and a thickness of 0.4 mm.

[0086] The thickness of the first air medium layer and the second air medium layer is 2.0 mm.

[0087] The base plate is made of carbon fiber plate with a thickness of 0.5mm.

[0088] The reflection coefficients in the TE and TM directions of this embodiment were obtained by simulating the dual-polarized absorbing superstructure using the electromagnetic simulation software CST Studio Suite. (See [link to relevant documentation]). Figure 5 The horizontal axis represents frequency, and the vertical axis represents reflected electromagnetic energy.

[0089] from Figure 5 It can be seen that the reflection coefficient is less than -10dB within the range of 4–18 GHz. Simulation results show that the absolute operating bandwidth of this embodiment is greater than 14 GHz, the relative bandwidth reaches 140%, the absorption rate within the absorption bandwidth is greater than 90%, and the thickness of the dual-polarized absorbing superstructure is only 0.173λ0 (where λ0 is the wavelength corresponding to the absorption center frequency).

[0090] Example 2

[0091] This embodiment provides a dual-polarized absorbing superstructure, comprising a first dielectric plate, a fractal absorbing resistive film, a first air dielectric layer, a second dielectric plate, a square ring fractal absorbing resistive film, a second air dielectric layer, and a base plate stacked sequentially.

[0092] The side length of the dual-polarized absorbing superstructure is 20 mm.

[0093] In the fractal absorbing resistive film, the period of the structural unit is L = 20 mm, and the transverse sin function curve and the longitudinal sin function curve are x = A. x ×sin(ω x ×t x +φ x A x =0.55, ω x =0.35π, φ x =0,t x =6.0, the horizontal cosine function curve and the vertical cosine function curve y=A y ×cos(ω y ×t y +φ y ),

[0094] A y =0.55, ω y =0.35π, φ y =0,t y =6.0, sheet resistance is 55Ω / sq.

[0095] In the square ring fractal absorbing resistor film, the outer width of the square ring is 11mm and the inner width is 6mm. The transverse sin function curve and the longitudinal sin function curve x=A x ×sin(ω x ×t x +φ x A x =0.275, ω x =0.35π, φ x =0,t x =3.0, the horizontal cosine function curve and the vertical cosine function curve y=A y ×cos(ω y ×t y +φ y A y =0.275, ω y =0.35π, φ y =0,t y =3.0, sheet resistance is 380Ω / sq.

[0096] Both the first and second dielectric substrates are made of glass fiber epoxy resin boards with a relative permittivity of 4.8 and a thickness of 0.6 mm.

[0097] The thickness of the first air medium layer and the second air medium layer is 2.5 mm.

[0098] The base plate is made of carbon fiber plate with a thickness of 0.4mm.

[0099] The reflection coefficients in the TE and TM directions of this embodiment were obtained by simulating the dual-polarized absorbing superstructure using the electromagnetic simulation software CST Studio Suite. Within the 4–18 GHz range, the reflection coefficient is less than -10 dB. Simulation results show that the absolute operating bandwidth of this embodiment is greater than 14 GHz, the relative bandwidth reaches 138%, the absorption rate within the absorption bandwidth is greater than 90%, and the thickness of the dual-polarized absorbing superstructure is only 0.175λ0 (where λ0 is the wavelength corresponding to the absorption center frequency).

[0100] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A microwave absorbing resistive film, characterized in that, Includes a square ring and a fractal layer located within the area of ​​the square ring; The fractal layer is a mesh structure composed of sine and cosine function curves, and the pattern of the fractal layer is symmetrical with respect to the center point of the fractal layer.

2. The microwave absorbing resistive film according to claim 1, characterized in that, The horizontal and vertical center lines of the fractal layer divide the fractal layer into four regions, which are, in a clockwise direction, the first region corresponding to the first quadrant, the second region corresponding to the second quadrant, the third region corresponding to the third quadrant, and the fourth region corresponding to the fourth quadrant.

3. The microwave absorbing resistive film according to claim 2, characterized in that, Both the first and third regions include multiple horizontal sine function curves and multiple vertical cosine function curves.

4. The microwave absorbing resistive film according to claim 2, characterized in that, Both the second and fourth regions include multiple horizontal cosine function curves and multiple vertical sinine function curves.

5. The microwave absorbing resistive film according to claim 1, characterized in that, In the fractal layer, the inner width of the square ring is 5-6 mm, and the outer width is 11-13 mm.

6. A dual-polarization absorbing superstructure, characterized in that, It includes a square ring fractal absorbing resistive film, wherein the square ring fractal absorbing resistive film is the absorbing resistive film as described in any one of claims 1 to 5.

7. The dual-polarized absorbing superstructure according to claim 6, characterized in that, It also includes a first dielectric substrate, a first air dielectric layer, a second dielectric substrate, a fractal absorbing resistive film, a second air dielectric layer, and a base plate, which are stacked sequentially from top to bottom.

8. The dual-polarized absorbing superstructure according to claim 7, characterized in that, The pattern of the fractal absorbing resistive film is symmetrical with respect to the center point of the fractal absorbing resistive film.

9. The dual-polarized absorbing superstructure according to claim 8, characterized in that, The pattern shape of the fractal layer is exactly the same as that of the fractal absorbing resistive film, with a size ratio of 2-3:5-6.

10. A method for fabricating a dual-polarized absorbing superstructure, characterized in that, The fabrication method for the dual-polarized absorbing superstructure as described in any one of claims 6 to 9 comprises the following steps: Provide a base plate; A second air dielectric layer, a square ring fractal absorbing resistive film, a second dielectric plate, a first air dielectric layer, a fractal absorbing resistive film, and a first dielectric plate are sequentially formed on the base plate to obtain a dual-polarized absorbing superstructure.

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