Frequency selective surface composite wave-absorbing device of high-bearing wave-absorbing integrated structure

Abstract

The invention discloses a multi-layer resistive film frequency selective surface composite wave-absorbing device with high bearing and wave-absorbing integrated functional characteristics. The composite wave absorbing device sequentially comprises a mechanical bearing layer composed of a wave-transparent dielectric plate subjected to impedance modification and a dielectric isolation layer from top to bottom. The wave-absorbing functional layer is formed by arranging three layers of resistive film frequency selective surfaces, three layers of dielectric isolation layers and six layers of wave-transparent dielectric plates at intervals; and the total reflection bottom plate is formed by a carbon fiber plate or a metal plate. According to the invention, a layer of resistive film frequency selective surface is embedded in the wave-transparent dielectric plate, so that the wave-absorbing bandwidth can be effectively expanded while the high-bearing mechanical property is ensured; a layer of wave-transparent dielectric plate is laid on the upper portion and the lower portion of the frequency selective surface of each resistive film in the wave-absorbing functional layer so as to further reinforce the mechanical bearing characteristic of the composite wave-absorbing device.

Description

Technical Field

[0001] The present invention relates to the technical field of composite absorbing materials, and in particular to a multilayer resistive film frequency selective surface composite absorbing device with high load-bearing integrated absorbing functional characteristics, which is suitable for equipment such as aircraft skins and ship bulwarks that require both structural strength and broadband absorbing performance. Background Art

[0002] As radar detection technology develops rapidly towards wide frequency band and wide angle, the electromagnetic stealth requirements of targets have been continuously promoted from single frequency band absorption to wide band absorption, high stability and multi-functional integration. Radar absorbing structures achieve stealth function through electromagnetic loss mechanism. Its core principle is to convert the incident electromagnetic wave energy into heat energy through dielectric loss or hysteresis loss, thereby significantly reducing the radar scattering cross section of the target.

[0003] However, in typical application scenarios such as aviation, marine and land equipment, the design of absorbers faces more stringent multi-physics field coupling constraints. For example, on aircraft, the integrated composite absorber mainly needs to bear the aerodynamic load in the direction outside the skin surface; on ships, it needs to have both corrosion resistance and impact resistance; on ground armored vehicles, it is necessary to consider the bulletproof and impact-resistant design, which has greater requirements for structural mechanical strength. This puts different and higher requirements on the material selection and performance of the integrated composite absorber.

[0004] Generally speaking, resistive film frequency selective surface absorbing structures rely on layered designs to expand the absorbing bandwidth and enhance the loss of electromagnetic waves, but these designs often weaken the stiffness and load-bearing capacity of the material; and improving mechanical properties usually requires the introduction of high-strength components into the structure, which may destroy the impedance matching characteristics of the overall structure and lead to an increase in reflectivity. Therefore, a frequency selective surface composite absorbing device with a high-load-bearing integrated absorbing structure is proposed, which can significantly improve the absorbing performance and structural reliability of aircraft, ships and other equipment in actual combat environments. Summary of the invention

[0005] The resistive film frequency selective surface absorbing structure achieves controllable dissipation of electromagnetic energy while retaining the spatial filtering characteristics. This type of structure combines the resistance loss mechanism with the frequency selective surface spatial filtering characteristics through the design of multi-layer impedance matching, and is a typical structural absorbing material. Based on the current research status of its electromagnetic properties and mechanical properties, and combined with existing technical defects and improvement needs, the present invention provides a multi-layer resistive film frequency selective surface composite absorbing device with high load-bearing integrated absorbing functional characteristics, the purpose of which is to solve the problem of mutual restriction between mechanical strength and absorbing performance.

[0006] According to the first aspect of the present invention, there is provided a frequency selective surface composite absorbing device with a high load-bearing and absorbing integrated structure, which sequentially includes a mechanical load-bearing layer, an absorbing functional layer, and a total reflection bottom plate from top to bottom:

[0007] The mechanical load-bearing layer includes a first wave-transmitting dielectric plate, a first resistive film frequency selective surface layer, and a first dielectric isolation layer; the first resistive film frequency selective surface layer is embedded in the first wave-transmitting dielectric plate for impedance modification of the first wave-transmitting dielectric plate to expand the absorbing bandwidth; the first dielectric isolation layer is located at the bottom of the first wave-transmitting dielectric plate;

[0008] The absorbing functional layer includes, from top to bottom, a second wave-transmitting dielectric plate, a second resistive film frequency selective surface absorbing layer, a third wave-transmitting dielectric plate, a second dielectric isolation layer, a fourth wave-transmitting dielectric plate, a third resistive film frequency selective surface absorbing layer, a fifth wave-transmitting dielectric plate, a third dielectric isolation layer, a sixth wave-transmitting dielectric plate, a fourth resistive film frequency selective surface absorbing layer, a seventh wave-transmitting dielectric plate, and a fourth dielectric isolation layer; the unit spacing, line width, and sheet resistance of the resistive film patterns of the second resistive film frequency selective surface absorbing layer, the third resistive film frequency selective surface absorbing layer, and the fourth resistive film frequency selective surface absorbing layer are different;

[0009] The total reflection bottom plate is located at the bottom of the overall composite absorbing device.

[0010] Preferably, the materials of the first wave-transmitting dielectric plate, the second wave-transmitting dielectric plate, the third wave-transmitting dielectric plate, the fourth wave-transmitting dielectric plate, the fifth wave-transmitting dielectric plate, the sixth wave-transmitting dielectric plate, and the seventh wave-transmitting dielectric plate are independently selected from glass fiber prepreg, quartz fiber prepreg, or aramid fiber prepreg materials.

[0011] Preferably, the dielectric constant value ε0 of the first wave-transmitting dielectric plate, the second wave-transmitting dielectric plate, the third wave-transmitting dielectric plate, the fourth wave-transmitting dielectric plate, the fifth wave-transmitting dielectric plate, the sixth wave-transmitting dielectric plate, and the seventh wave-transmitting dielectric plate is <5, and the loss tangent value tanδ is <0.03.

[0012] Preferably, the materials of the first dielectric isolation layer, the second dielectric isolation layer, the third dielectric isolation layer, and the fourth dielectric isolation layer are independently selected from aramid honeycomb or PMI foam materials.

[0013] Preferably, the material of the total reflection bottom plate is carbon fiber plate or metal plate material.

[0014] Preferably, the period of the resistive film pattern of the first resistive film frequency selective surface layer is 8 mm - 12 mm, half of the unit spacing is 0.3 mm - 3 mm, the line width is 0.3 mm - 3 mm, and the sheet resistance is 50 ohm / sq - 250 ohm / sq.

[0015] Preferably, the periods of the resistive film patterns of the second resistive film frequency selective surface absorbing layer, the third resistive film frequency selective surface absorbing layer, and the fourth resistive film frequency selective surface absorbing layer are 8 mm - 12 mm, half of the inter-element spacing is 0.3 mm - 3 mm, the line width is 0.3 mm - 3 mm, and the sheet resistance is 50 ohm / sq - 250 ohm / sq.

[0016] Generally speaking, compared with the prior art, the above technical solutions proposed by the present invention can achieve the following beneficial effects:

[0017] (1) In the present invention, each layer of the wave-transparent dielectric plate is a prepreg material of different systems with high load-bearing mechanical properties, which has the performance advantage of "wave-transparent - load-bearing" in one. Each layer of the frequency selective surface is a resistive film lossy frequency selective surface, which realizes the controllable dissipation of electromagnetic energy while retaining the spatial filtering characteristics. The overall composite absorbing device has high bending stiffness and shear resistance, and is suitable for the lightweight requirements of aircraft or ships. It should be noted that in the present invention, a layer of resistive film frequency selective surface is embedded in the wave-transparent dielectric plate, which can effectively expand the absorption bandwidth while ensuring high load-bearing mechanical properties. A layer of wave-transparent dielectric plate is laid on both the upper and lower sides of each layer of the resistive film frequency selective surface in the absorbing functional layer to further strengthen the mechanical load-bearing characteristics of the composite absorbing device. At the same time, the impedance transformation of the wave-transparent dielectric plate is incorporated into the impedance matching design of the resistive film frequency selective surface to achieve precise impedance design and efficient absorption of electromagnetic waves.

[0018] (2) Different from the traditional frequency selective surface absorber, the present invention solves the integration of absorption performance and mechanical performance. Among them, the mechanical load-bearing layer of the present invention is mainly used to bear the out-of-plane load of the composite absorbing device, and has reliable mechanical strength and appropriate thickness, so as to improve the mechanical performance of the device. Preferably, each layer of the wave-transparent dielectric plate has a low dielectric constant value (ε0 < 5) and a low loss tangent value (tanδ < 0.03) to ensure the efficient penetration of electromagnetic waves. While meeting the requirements of high strength, lightweight and tolerance to extreme environments, the mechanical load-bearing layer can be conformal designed with a low RCS shape to meet the requirements of wave-transparency and load-bearing integration. The absorbing functional layer of the present invention is used to regulate the input impedance of the composite absorbing device so that it can match the impedance of free space, thereby reducing the reflection of electromagnetic waves and realizing the effective absorption of electromagnetic waves. Among them, the design of the multi-layer resistive film frequency selective surface can significantly expand the absorption bandwidth and realize the broadband absorption characteristics of the composite absorbing device.

[0019] (3) The present invention solves the problem that when the wave - transmitting dielectric plate meets the conditions of high strength and large thickness, the impedance matching of the composite absorbing device is unbalanced and the absorbing performance deteriorates. By using the resistive - film frequency - selective surface to modify the impedance of the wave - transmitting dielectric plate, the obtained composite absorbing device can still maintain an absorbing effect below - 10 dB in a wide frequency band of 1 - 8 GHz; moreover, the present invention compares the mechanical strength and absorbing performance of the composite absorbing device when two different material systems, namely glass fiber prepreg and quartz fiber prepreg, are used as the wave - transmitting dielectric plate.

[0020] (4) The present invention explores the influence of the substrate material and the upper and lower loaded wave - transmitting dielectric plates on the impedance of the resistive - film frequency - selective surface pattern. Through the precise design of the impedance of the absorbing layer of the resistive - film frequency - selective surface, it performs impedance transformation jointly with the dielectric isolation layer to complete the matching with the air impedance and achieve the efficient absorption of electromagnetic waves. At the same time, the problem of the performance instability of the resistive - film functional layer during packaging is solved by means of coating a patterned protective layer. Finally, a multi - layer resistive - film frequency - selective surface composite absorbing device with the integrated function characteristics of high load - bearing and wave absorption can be designed. Description of the Drawings

[0021] Figure 1 is a schematic structural diagram of a multi - layer resistive - film frequency - selective surface composite absorbing device with the integrated function characteristics of high load - bearing and wave absorption provided by the present invention.

[0022] Figure 2 is a three - dimensional array structural diagram of the multi - layer resistive - film frequency - selective surface composite absorbing device with the integrated function characteristics of high load - bearing and wave absorption provided by Embodiment 1, 2 and 3 of the present invention.

[0023] Figure 3 is a distribution diagram of the resistive - film patterns of each layer of the multi - layer resistive - film frequency - selective surface composite absorbing device with the integrated function characteristics of high load - bearing and wave absorption provided by Embodiment 1, 2 and 3 of the present invention.

[0024] Figure 4 is a comparison of the reflectivity characteristic curves of the multi - layer resistive - film frequency - selective surface composite absorbing device with the integrated function characteristics of high load - bearing and wave absorption provided by Embodiment 1 of the present invention under normal incidence.

[0025] Figure 5 is the displacement nephogram and MISES stress nephogram of the model of the multi - layer resistive - film frequency - selective surface composite absorbing device with the integrated function characteristics of high load - bearing and wave absorption provided by Embodiment 1 of the present invention when the four sides of the model are fixed and a pressure load of 0.03 MPa is applied.

[0026] Figure 6It is a comparison of the reflectivity characteristic curves of the multi-layer resistive film frequency selective surface composite absorbing device with the characteristics of high load-bearing and wave absorption under normal incidence provided in Embodiment 2 of the present invention.

[0027] Figure 7 It is the displacement nephogram and MISES stress nephogram when the model of the multi-layer resistive film frequency selective surface composite absorbing device with the characteristics of high load-bearing and wave absorption provided in Embodiment 2 of the present invention is fixed at four sides and a pressure load of 0.03 MPa is applied.

[0028] Figure 8 It is a comparison of the reflectivity characteristic curves of the multi-layer resistive film frequency selective surface composite absorbing device with the characteristics of high load-bearing and wave absorption under normal incidence provided in Embodiment 3 of the present invention.

[0029] Figure 9 It is the displacement nephogram and MISES stress nephogram when the model of the multi-layer resistive film frequency selective surface composite absorbing device with the characteristics of high load-bearing and wave absorption provided in Embodiment 3 of the present invention is fixed at four sides and a pressure load of 0.03 MPa is applied.

[0030] In all the attached drawings, the same reference numerals represent the same components, where: 1 - the first wave-transmitting dielectric plate, 2 - the first resistive film frequency selective surface layer, 3 - the first dielectric isolation layer, 4 - the second wave-transmitting dielectric plate, 5 - the second resistive film frequency selective surface absorbing layer, 6 - the third wave-transmitting dielectric plate, 7 - the second dielectric isolation layer, 8 - the fourth wave-transmitting dielectric plate, 9 - the third resistive film frequency selective surface absorbing layer, 10 - the fifth wave-transmitting dielectric plate, 11 - the third dielectric isolation layer, 12 - the sixth wave-transmitting dielectric plate, 13 - the fourth resistive film frequency selective surface absorbing layer, 14 - the seventh wave-transmitting dielectric plate, 15 - the fourth dielectric isolation layer, 16 - the total reflection bottom plate. Detailed implementation manners

[0031] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the attached drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] Generally speaking, the composite absorbing device is composed of a plurality of unit structures arranged in a row and column period, and each unit structure is as Figure 1 shown, and the overall three-dimensional array structure is as Figure 2 shown. The present invention sequentially includes a mechanical load-bearing layer, a wave absorption functional layer and a total reflection bottom plate from top to bottom:

[0033] The mechanical load-bearing layer includes a first wave-transmitting dielectric plate 1, a first resistive film frequency selective surface layer 2, and a first dielectric isolation layer 3; the first resistive film frequency selective surface layer 2 is embedded in the first wave-transmitting dielectric plate 1, and the first dielectric isolation layer 3 is located at the bottom of the first wave-transmitting dielectric plate 1;

[0034] The wave-absorbing functional layer from top to bottom includes a second wave-transmitting dielectric plate 4, a second resistive film frequency selective surface wave-absorbing layer 5, a third wave-transmitting dielectric plate 6, a second dielectric isolation layer 7, a fourth wave-transmitting dielectric plate 8, a third resistive film frequency selective surface wave-absorbing layer 9, a fifth wave-transmitting dielectric plate 10, a third dielectric isolation layer 11, a sixth wave-transmitting dielectric plate 12, a fourth resistive film frequency selective surface wave-absorbing layer 13, a seventh wave-transmitting dielectric plate 14, and a fourth dielectric isolation layer 15;

[0035] The total reflection bottom plate 16 is located at the bottom of the overall composite wave-absorbing device.

[0036] Considering the integrated design of high load-bearing performance and wave-absorbing performance. The present invention takes into account the influence of dielectric loading on the performance of the wave-absorbing structure. Therefore, the substrate material of the resistive film and the upper and lower loaded wave-transmitting dielectric plates and the resistive film frequency selective surface pattern layer are taken as a whole for impedance analysis, which simplifies the impedance matching process and achieves the purpose of quickly designing the wave-absorbing body.

[0037] In some alternative embodiments, the thickness of the wave-transmitting skin (the first wave-transmitting dielectric plate) of the present invention is set to 3 mm to simulate the design process of the composite wave-absorbing device when a large-thickness skin is loaded under extreme strength requirements. It should be noted that a layer of resistive film frequency selective surface is embedded in the wave-transmitting dielectric plate for impedance modification to expand the wave-absorbing bandwidth.

[0038] In some alternative embodiments, the resistive film frequency selective surface used in the wave-absorbing functional layer of the composite wave-absorbing device is composed of multiple units arranged in a row and column period, and each layer of the resistive film frequency selective surface pattern has different sizes and sheet resistances.

[0039] In some alternative embodiments, a polyurethane-modified epoxy resin system material is used to pattern and protect the pattern of the resistive film frequency selective surface functional layer, making the performance of the resistive film frequency selective surface more stable. At the same time, it provides an interlayer bonding space and realizes the mechanical load-bearing characteristics under stable wave-absorbing performance.

[0040] In some alternative embodiments, wave-transmitting dielectric plates with a thickness of 0.5 mm are loaded above and below each layer of the resistive film frequency selective surface to further enhance the mechanical strength of the overall structure.

[0041] In some alternative embodiments, the above total reflection bottom plate is a total reflection surface composed of a carbon fiber plate.

[0042] The absorbing frequency band of the absorbing and load-bearing absorbing device provided by the present invention covers 1 - 8 GHz. To further illustrate the absorbing and load-bearing characteristics of the multi-layer resistive film frequency selective surface composite absorbing device with the integrated function of high load-bearing and wave absorption, taking N = 3 as an example, it will be further described in detail in combination with the embodiments.

[0043] The following are specific implementation cases:

[0044] Embodiment 1

[0045] A multi-layer resistive film frequency selective surface composite absorbing device with the integrated function of high load-bearing and wave absorption, as Figure 1 shown, from top to bottom, it successively includes a first wave-transmitting dielectric plate 1 (made of glass fiber system, relative dielectric constant is 4.4, loss tangent value is 0.02, thickness is 3 mm), a first resistive film frequency selective surface functional layer 2, a first dielectric isolation layer 3 (made of PMI foam, relative dielectric constant is 1.1, loss tangent value is 0.002), a second wave-transmitting dielectric plate 4 (made of glass fiber system, relative dielectric constant is 4.4, loss tangent value is 0.02, thickness 0.5 mm), a second resistive film frequency selective surface functional layer 5, a third wave-transmitting dielectric plate 6 (made of glass fiber system, relative dielectric constant is 4.4, loss tangent value is 0.02, thickness is 0.5 mm), a second dielectric isolation layer 7 (made of PMI foam, relative dielectric constant is 1.1, loss tangent value is 0.002), a fourth wave-transmitting dielectric plate 8 (made of glass fiber system, relative dielectric constant is 4.4, loss tangent value is 0.02, thickness is 0.5 mm), a third resistive film frequency selective surface functional layer 9, a fifth wave-transmitting dielectric plate 10 (made of glass fiber system, relative dielectric constant is 4.4, loss tangent value is 0.02, thickness is 0.5 mm), a third dielectric isolation layer 11 (made of PMI foam, relative dielectric constant is 1.1, loss tangent value is 0.002), a sixth wave-transmitting dielectric plate 12 (made of glass fiber system, relative dielectric constant is 4.4, loss tangent value is 0.02, thickness is 0.5 mm), a fourth resistive film frequency selective surface functional layer 13, a seventh wave-transmitting dielectric plate 14 (made of glass fiber system, relative dielectric constant is 4.4, loss tangent value is 0.02, thickness is 0.5 mm), a fourth dielectric isolation layer 15 (made of PMI foam, relative dielectric constant is 1.1, loss tangent value is 0.002) and a total reflection bottom plate 16.

[0046] The period p of the overall structural unit is 10 mm × 10 mm. Each layer of the resistive film frequency selective surface is composed of multiple units arranged in a row and column period, and the pattern of each layer of the resistive film frequency selective surface has different sizes and sheet resistances. As Figure 3, half of the unit spacing g1 of the FSS pattern of the first resistive film frequency selective surface functional layer 2 is 1.1 mm, and the line width w1 is 3 mm; half of the unit spacing g2 of the FSS pattern of the second resistive film frequency selective surface functional layer 5 is 0.3 mm, and the line width w2 is 2 mm; half of the unit spacing g3 of the FSS pattern of the third resistive film frequency selective surface functional layer 9 is 0.8 mm, and the line width w3 is 2 mm; the unit gap g4 of the FSS pattern of the fourth resistive film frequency selective surface functional layer 13 is 3 mm, and the line width w4 is 1.6 mm.

[0047] In the electromagnetic simulation software HFSS, the reflectivity of the composite wave-absorbing device under normal incidence conditions was calculated. The characteristics of the reflectivity of the wave-absorbing device under normal incidence are as Figure 4 shown. It can be seen that in the case of loading a thick wave-transparent skin (the first wave-transparent dielectric plate), the wave-absorbing performance of the composite wave-absorbing device under normal incidence conditions can achieve a reflectivity reduction effect of -10 dB in the frequency range of 1 - 8 GHz.

[0048] In the ANSYS Workbench finite element analysis software, taking the composite wave-absorbing device in this case as the input condition, a structural model was established. The four sides of the structural model were fixed, and a pressure load of 0.03 MPa was applied to simulate the stress state of the aircraft skin structure. The output results are as Figure 5 shown. It can be seen that the maximum displacement generated on the surface of the structural model is 0.135 mm, and the highest MISES stress is 7.15 Mpa. Comparing Example 2 and Example 3, the mechanical properties of the structural model using epoxy glass fiber prepreg as the wave-transparent dielectric plate and PMI foam as the dielectric isolation layer are the best.

[0049] Example 2

[0050] Based on the composite wave-absorbing device model given in Example 1, the wave-transparent dielectric plate and the dielectric isolation layer were set to different material systems. Specifically, the materials of the wave-transparent dielectric plates were all replaced with quartz fiber systems (relative permittivity 3.34, loss tangent 0.004); the materials of the dielectric isolation layers were all replaced with aramid paper honeycombs (relative permittivity 1.07, loss tangent 0.0017). The period of the overall structural unit is 10 mm × 10 mm. The pattern of the resistive film frequency selective surface functional layer remains unchanged.

[0051] In the electromagnetic simulation software HFSS, the reflectivity under normal incidence conditions was calculated. The reflectivity characteristics of the wave-absorbing device under normal incidence are as Figure 6As shown, it can be seen that compared with the prepreg of the glass fiber system with higher dielectric and higher loss (relative dielectric constant 4.4, loss tangent 0.02), the prepreg of the quartz fiber system can achieve a wider absorption bandwidth as a wave-transparent dielectric plate.

[0052] Taking this embodiment as the input condition, a finite element model is established. The four sides of the structural model are fixed, and a pressure load of 0.03 MPa is applied to simulate the stress state of the aircraft skin structure. The output results are as Figure 7 shown. The maximum displacement generated on the surface of the overall structure is 0.27 mm, and the highest MISES stress is 11.32 Mpa.

[0053] Example 3

[0054] Based on the composite wave-absorbing device model given in Example 1, the dielectric isolation layer is set to different material systems. Specifically, the materials of the dielectric isolation layer are all replaced with aramid paper honeycomb (relative dielectric constant 1.07, loss tangent 0.0017). The period of the overall structural unit is 10 mm × 10 mm. The pattern of the resistive film frequency selective surface functional layer remains unchanged.

[0055] In the electromagnetic simulation software HFSS, the reflectivity calculation under normal incidence conditions is carried out. The characteristics of the reflectivity of the wave-absorbing device under normal incidence are as Figure 8 shown. It can be seen that the two selected materials of the dielectric isolation layer have no significant influence on the wave-absorbing performance of the composite wave-absorbing device.

[0056] Taking this example as the input condition, a finite element model is established. The four sides of the model are fixed, and a pressure load of 0.03 MPa is applied to simulate the stress state of the aircraft skin structure. The output results are as Figure 9 shown. The maximum displacement generated on the surface of the overall structure is 0.28 mm, and the highest MISES stress is 9.85 Mpa. Comparing with Example 1, it can be seen that using PMI foam as the dielectric isolation layer can achieve better mechanical bearing performance.

[0057] Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A frequency selective surface composite absorbing device with a high load-bearing and wave-absorbing integrated structure, characterized in that It includes a mechanical load-bearing layer, an electromagnetic wave absorbing functional layer, and a total reflection bottom plate (16) from top to bottom in sequence: The mechanical load-bearing layer includes a first wave-transmitting dielectric plate (1), a first resistive film frequency selective surface layer (2), and a first dielectric isolation layer (3); the first resistive film frequency selective surface layer (2) is embedded in the first wave-transmitting dielectric plate (1) for impedance modification of the first wave-transmitting dielectric plate (1) to expand the electromagnetic wave absorption bandwidth; the first dielectric isolation layer (3) is located at the bottom of the first wave-transmitting dielectric plate (1); The electromagnetic wave absorbing functional layer includes a second wave-transmitting dielectric plate (4), a second resistive film frequency selective surface electromagnetic wave absorbing layer (5), a third wave-transmitting dielectric plate (6), a second dielectric isolation layer (7), a fourth wave-transmitting dielectric plate (8), a third resistive film frequency selective surface electromagnetic wave absorbing layer (9), a fifth wave-transmitting dielectric plate (10), a third dielectric isolation layer (11), a sixth wave-transmitting dielectric plate (12), a fourth resistive film frequency selective surface electromagnetic wave absorbing layer (13), a seventh wave-transmitting dielectric plate (14), and a fourth dielectric isolation layer (15) from top to bottom; the unit spacing, line width, and sheet resistance of the resistive film patterns of the second resistive film frequency selective surface electromagnetic wave absorbing layer (5), the third resistive film frequency selective surface electromagnetic wave absorbing layer (9), and the fourth resistive film frequency selective surface electromagnetic wave absorbing layer (13) are different; The total reflection bottom plate (16) is located at the bottom of the overall composite electromagnetic wave absorbing device.

2. The multi-layer resistor film frequency selective surface composite wave-absorbing device according to claim 1, wherein The materials of the first wave-transmitting dielectric plate (1), the second wave-transmitting dielectric plate (4), the third wave-transmitting dielectric plate (6), the fourth wave-transmitting dielectric plate (8), the fifth wave-transmitting dielectric plate (10), the sixth wave-transmitting dielectric plate (12), and the seventh wave-transmitting dielectric plate (14) are made of glass fiber prepreg, quartz fiber prepreg, or aramid fiber prepreg materials.

3. The multi-layer resistive film frequency selective surface composite absorbing device according to claim 1, characterized in that, The dielectric constant value ε0 of the first wave-transmitting dielectric plate (1), the second wave-transmitting dielectric plate (4), the third wave-transmitting dielectric plate (6), the fourth wave-transmitting dielectric plate (8), the fifth wave-transmitting dielectric plate (10), the sixth wave-transmitting dielectric plate (12), and the seventh wave-transmitting dielectric plate (14) is <5, and the loss tangent value tanδ is <0.

03.

4. The multi-layer resistive film frequency selective surface composite wave-absorbing device according to claim 1, characterized in that, The materials of the first dielectric isolation layer (3), the second dielectric isolation layer (7), the third dielectric isolation layer (11), and the fourth dielectric isolation layer (15) are independently selected from aramid honeycomb or PMI foam materials.

5. The multi-layer resistor film frequency selective surface composite wave-absorbing device according to claim 1, characterized in that The material of the total reflection bottom plate (16) is a carbon fiber plate or a metal plate material.

6. The multi-layer resistive film frequency selective surface composite wave-absorbing device according to claim 1, wherein The period of the resistive film pattern of the first resistive film frequency selective surface layer (2) is 8 mm - 12 mm, half of the unit spacing is 0.3 mm - 3 mm, the line width is 0.3 mm - 3 mm, and the sheet resistance is 50 ohm / sq - 250 ohm / sq.

7. The multi-layer resistive film frequency selective surface composite wave-absorbing device according to claim 1, characterized in that, The period of the resistive film patterns of the second resistive film frequency selective surface electromagnetic wave absorbing layer (5), the third resistive film frequency selective surface electromagnetic wave absorbing layer (9), and the fourth resistive film frequency selective surface electromagnetic wave absorbing layer (13) is 8 mm - 12 mm, half of the unit spacing is 0.3 mm - 3 mm, the line width is 0.3 mm - 3 mm, and the sheet resistance is 50 ohm / sq - 250 ohm / sq.

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