A wave-absorbing honeycomb structure of a transverse loading resistance film and an interference prevention device

Abstract

The utility model discloses a kind of wave-absorbing honeycomb structures and anti-interference equipment of transverse loading resistance film, wave-absorbing honeycomb structure can include: multiple absorption units sequentially arranged in the same plane;Each absorption unit includes: hexagonal honeycomb matrix and at least one transverse resistance film located in the hexagonal honeycomb matrix, the transverse resistance film is perpendicular to the central axis of the hexagonal honeycomb matrix. By loading at least one layer of transverse resistance film in hexagonal honeycomb matrix, the absorption performance of wave-absorbing honeycomb structure can be greatly improved. At the same time, due to the avoidance of complex multilayer structure design, a rapid simulation optimization process is achieved, and the complexity of the production process is also reduced.

Description

Technical Field

[0001] This utility model relates to the field of electromagnetic wave absorbing materials technology, and in particular to a wave absorbing honeycomb structure with a transversely loaded resistive film and an anti-interference device. Background Technology

[0002] With the rapid development of modern technology, the operating frequency bands of systems such as wireless communication and radar detection are constantly expanding. Whether in the civilian field, such as 5G communication and electromagnetic interference protection for electronic equipment, or in other technological fields such as aircraft stealth, the demand for high-performance broadband absorbers is becoming increasingly urgent.

[0003] Absorbing honeycomb structures are widely used in aerospace stealth equipment and electromagnetic compatibility fields due to their lightweight, high load-bearing capacity, and integrated absorption properties. Traditional absorbing honeycomb structures mainly achieve electromagnetic loss by coating the honeycomb cell walls with an absorbing coating through an impregnation process. However, their absorption performance is limited in certain frequency bands and cannot meet the growing demand for high-performance absorption. With the development of electronic technology, higher requirements are being placed on absorbing materials in terms of wider frequency bands and higher absorption rates. Utility Model Content

[0004] To address the technical challenges of complex patterns and lengthy simulation optimization times resulting from adding multiple layers to absorbing honeycomb structures, and to ensure the overall shape and adjustability of the resistive film of the absorbing honeycomb structure, this invention provides a corresponding fabrication method.

[0005] As one aspect of this utility model, an embodiment of this utility model provides a microwave absorbing honeycomb structure with a transversely loaded resistive film, which may include: a plurality of microwave absorbing units arranged sequentially on the same plane;

[0006] Each absorbing unit may include: a hexagonal honeycomb substrate and at least one transverse resistive film located within the hexagonal honeycomb substrate, the transverse resistive film being perpendicular to the central axis of the hexagonal honeycomb substrate.

[0007] In one embodiment, the absorbing unit further includes foam located at the openings of the transverse resistive film and the hexagonal honeycomb substrate.

[0008] In one embodiment, the position of the lateral resistive film within the hexagonal honeycomb substrate is adjustable, and the resistance of the lateral resistive film is not higher than 600Ω / sq.

[0009] In one embodiment, the hexagonal honeycomb substrate has a side length of 3 mm, a wall thickness of 0.06 mm or 0.13 mm, and a height of 30 mm.

[0010] In one embodiment, the real part of the dielectric constant of the inner wall of the hexagonal honeycomb substrate is 2.3~55, and the dielectric tangent is 0.001~0.5.

[0011] As another aspect of this utility model, an embodiment of this utility model provides an anti-interference device, wherein the outer surface of the anti-interference device is attached with the above-mentioned transversely loaded resistive film absorbing honeycomb structure.

[0012] As another aspect of this utility model, an embodiment of this utility model provides an application of the above-mentioned transversely loaded resistive film absorbing honeycomb structure in an anti-interference device.

[0013] The beneficial effects of the above-mentioned technical solutions provided in the embodiments of this utility model include at least the following:

[0014] This invention provides an absorbing honeycomb structure with a transversely loaded resistive film and an anti-interference device. By loading at least one transverse resistive film into a hexagonal honeycomb matrix, the absorption performance of the absorbing honeycomb structure can be greatly improved. At the same time, by avoiding complex multi-layer structure design, a rapid simulation optimization process is achieved, and the complexity of the production process is reduced.

[0015] Compared with the prior art, the method for fabricating the absorbing honeycomb structure of the transversely loaded resistive film of this invention can completely reproduce the simulation design scheme of the transversely loaded resistive film of this invention, and the structure is stable. Other features and advantages of this invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained by means of the structures particularly pointed out in the written description and drawings.

[0016] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0018] Figure 1 This is a structural diagram of the microwave absorbing honeycomb structure of the transversely loaded resistive film provided in the embodiments of this utility model;

[0019] Figure 2 This is a simulation result diagram of the reflection coefficient of the absorbing honeycomb structure with transversely loaded resistive film provided in Embodiment 1 of this utility model, showing the change in loading height.

[0020] Figure 3The simulation results of the reflection coefficient of the absorbing honeycomb structure with transversely loaded resistive film provided in Embodiment 1 of this utility model are shown in the figure.

[0021] Figure 4 This is a simulation result diagram of the reflection coefficient of the absorbing honeycomb structure with transversely loaded resistive film provided in Embodiment 2 of this utility model, showing the change in loading height.

[0022] Figure 5 This is a simulation result diagram of the reflection coefficient of the absorbing honeycomb structure with transversely loaded resistive film provided in Embodiment 2 of this utility model, showing the change in loading resistance.

[0023] Figure 6 The simulation results of the reflection coefficient of the absorbing honeycomb structure with two transverse resistive films provided in Embodiment 3 of this utility model are shown.

[0024] Figure 7 This is a simulation result diagram of the reflection coefficient of the absorbing honeycomb structure with transversely loaded resistive film provided in Embodiment 4 of this utility model, showing the change in loading height.

[0025] Figure 8 This is a simulation result diagram of the reflection coefficient of the absorbing honeycomb structure with transversely loaded resistive film provided in Embodiment 4 of this utility model, showing the change in loading resistance.

[0026] Among them, 1-wave-absorbing honeycomb structure with transversely loaded resistive film; 2-metal reflector;

[0027] 11-Absorbing unit;

[0028] 111-Hexagonal honeycomb substrate; 112-Transverse resistive film. Detailed Implementation

[0029] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0030] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "far," "near," "front," and "rear," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0032] During their work and research, the inventors discovered that metamaterials, due to their shape designability and excellent electromagnetic properties, can be combined with other wave-absorbing materials to achieve ideal wave-absorbing performance by integrating the advantages of multiple materials. Through search and analysis, the inventors found that the design of many metamaterials combined with honeycomb structures includes the following types, specifically: (1) Metamaterial design at the bottom of the honeycomb (not inside the honeycomb), such as patent documents with publication numbers CN116454643A and CN114883812A; (2) Metamaterial design for the honeycomb wall, such as patent document with publication number CN119767658A; (3) Metamaterial design for the inside and surface of the honeycomb, such as patent documents with publication numbers CN116826389A, CN117578091A and CN120389233A.

[0033] The metamaterial designs inside and on the surface of the honeycomb structure offer high design flexibility and significantly improve wave absorption. Most of these designs involve the use of resistive films, as mentioned in the aforementioned patent documents. Patents with publication numbers CN117578091A and CN120389233A both feature integrated designs using multiple materials. While CN120389233A touches on the idea of ​​detachable components, it focuses on the individual or combined use of low-frequency absorbing structures (combining multiple materials) and high-frequency absorbing structures (primarily circuit boards), without using the resistive film as a separate design unit integrated with the honeycomb structure. Patent CN116826389A focuses on absorbing materials (including absorbing honeycomb) and resistive films, but the resistive film is composited on the outer surface of the absorbing material rather than inside the honeycomb structure.

[0034] The inventors, through further research on the design of multi-layer structures within existing absorbing honeycomb structures, discovered several problems associated with this approach: 1) The complex patterns and excessive number of layers in multi-layer structures increase the number of process steps and reduce production efficiency; 2) Too many influencing factors need to be considered during the design process, such as the electromagnetic properties of each layer's materials and interlayer coupling, leading to excessively long simulation and optimization times, increasing R&D costs and timelines; 3) Current multi-layer honeycomb designs focus on stacking, i.e., layer-by-layer design. However, because the continuous honeycomb structure is disrupted after stacking, there is a risk of misalignment between the honeycomb holes in the upper and lower layers of the layered or membrane structure, resulting in misalignment of the holes parallel to the surface. Applying force in the extension direction will cause shear force at the interface, which will damage the intermediate layered or film structure and affect the overall mechanical properties of the structure. If the force is applied from a direction that is not parallel to the extension direction of the hole, the honeycomb holes in the upper and lower layers of the layered or film structure are more likely to be misaligned. This risk of honeycomb misalignment will also affect the overall electromagnetic properties of the material. During the design process, the honeycomb holes in the upper and lower layers of the layered or film structure are completely aligned. The misalignment that actually occurs is an electromagnetic structure that was not considered during the design process, which may lead to a difference between the design and the actual electromagnetic properties. 4) The design of multi-layer layup requires cutting honeycomb of different thicknesses. The honeycomb height is fixed. If there are other performance requirements later, the height cannot be changed arbitrarily.

[0035] Addressing several drawbacks of existing multi-layered structures within the honeycomb of absorbing honeycomb structures, the inventors unexpectedly discovered that electromagnetic wave absorption performance was greatly improved by setting a transverse resistive film within a hexagonal honeycomb matrix, achieving unforeseen technical results.

[0036] This invention provides an absorbing honeycomb structure with a laterally loaded resistive film, as shown in the following embodiment. Figure 1As shown, the absorbing honeycomb structure 1 with the transversely loaded resistive film may include: a plurality of absorbing units 11 arranged sequentially on the same plane; each absorbing unit 11 may include: a hexagonal honeycomb substrate 111 and at least one transverse resistive film 112 located within the hexagonal honeycomb substrate 111, the transverse resistive film 112 being perpendicular to the central axis of the hexagonal honeycomb substrate 111.

[0037] In this embodiment, by loading at least one layer of transverse resistive film 112 into the hexagonal honeycomb substrate 111, the absorption performance of the absorbing honeycomb structure can be greatly improved. At the same time, by avoiding complex multi-layer structure design, a rapid simulation optimization process is achieved, and the complexity of the manufacturing process is also reduced.

[0038] In one embodiment, refer to Figure 1 As shown, the position of the lateral resistive film 112 within the hexagonal honeycomb substrate 111 is adjustable, and the resistance of the lateral resistive film 112 is not higher than 600 Ω / sq. In this embodiment, the hexagonal honeycomb substrate 111 has a side length of 3 mm, a wall thickness of 0.13 mm, and a height of 30 mm. Preferably, the real part of the dielectric constant of the inner wall of the hexagonal honeycomb substrate 111 is 30, and the dielectric tangent is 0.5.

[0039] Based on the same inventive concept, this utility model embodiment also provides a method for preparing the above-mentioned transversely loaded resistive film absorbing honeycomb structure, and the application of the above-mentioned transversely loaded resistive film absorbing honeycomb structure in anti-interference equipment.

[0040] Based on the above embodiments, this utility model designed three groups of specific embodiments and comparative examples within each group for testing. Unless otherwise specified, all raw materials and instruments used in the following embodiments and comparative examples are commercially available. Among them:

[0041] The cellular components were purchased from Jiaxing Yagang Composite Materials Co., Ltd., model number CMAG-CNCK-3-48.

[0042] Conductive paint raw material: water-based carbon black conductive paint, resistance is 18~22Ω / sq / mil;

[0043] In the following embodiments of this invention, a metal reflector is placed on one side of the absorbing honeycomb structure during testing. This is done to simulate the ideal boundary conditions of a "semi-infinite" free space and achieve "zero transmission" of electromagnetic waves, thereby specifically evaluating the material's "absorption" performance rather than its "shielding" performance. It should be noted that this metal reflector is perpendicular to the central axis of the hexagonal honeycomb substrate and located on one side of multiple absorbing units. This metal reflector is not part of the absorbing honeycomb structure claimed in this invention, and those skilled in the art should not misunderstand it.

[0044] Example 1

[0045] The microwave absorbing honeycomb structure 1 with a transversely loaded resistive film provided in Embodiment 1 has a hexagonal honeycomb substrate 111 with a side length L=3mm, a wall thickness D=0.06mm, and a height W=30mm. The real part of the dielectric constant of the inner wall of the hexagonal honeycomb substrate 111 is set to 2.3, and the dielectric tangent is set to 0.001 to simulate the state of a white honeycomb without microwave absorbing paste. In this embodiment, the white honeycomb is made of aramid fiber paper, and the electromagnetic properties of the white honeycomb are referenced from the patent application publication number CN119767658A. A transverse resistive film 112 is loaded inside the microwave absorbing honeycomb structure (absorbing unit 11). Specifically, the plane of the transverse resistive film 112 is perpendicular to the depth direction of the honeycomb holes, and the transverse resistive film 112 covers all the microwave absorbing honeycomb holes. The distance i between the transverse resistive film 112 with a resistance r of 100Ω / sq and the metal reflector 2 varies from -1 to 30mm (excluding 0). When i = -1mm, the resistive film is placed below the metal reflector 2, and the reflectivity is not affected by the resistive film loading. Figure 2 The reflectance curves show that only one layer of transverse resistive film 112 is needed to achieve a lower reflectance than the honeycomb without it. The reflectance peak is lowest when i=4mm. Therefore, by fixing i=4mm and varying the resistance r of the transverse resistive film 112 from 0 to 700Ω / sq (excluding 0), the reflectance can be further improved. Figure 3 The reflectivity curves show that, as r varies from 0 to 600 Ω / sq, the reflectivity of the absorbing honeycomb structure with the lateral resistive film 112 applied has a frequency range less than -10 dB from 2 to 18 GHz. However, when r = 700 Ω / sq, the reflectivity is greater than -10 dB from 2 to 18 GHz.

[0046] The fabrication method for this transversely loaded resistive film-based absorbing honeycomb structure design is as follows:

[0047] S1: Preparation of poly(meth)acrylimide foam board

[0048] Weigh out 30g of methacrylic acid, 30g of methacrylonitrile, 0.1g of initiator azobisisobutyronitrile, 4g of foaming agent methanol, 1g of crosslinking agent calcium oxide, and 0.5g of nucleating agent titanium dioxide according to the weight ratio and add them to the reaction vessel. Stir mechanically for 2 hours to obtain a material mixture. Then pour the obtained material mixture into a mold, heat it to 45℃ in a water bath, polymerize for 105 hours, and then perform post-treatment in an oven, heating it to 180℃ for 2 hours to foam.

[0049] S2: Conductive paint is sprayed onto the surface of poly(meth)acrylimide foam board.

[0050] The foamed PMI foam board was cut into 4mm thick slices according to simulation results. Conductive paint was sprayed onto the surface of the slices using a spray gun to form a resistive film. The nozzle size was 0.5mm and the distance between the nozzle and the carrier was 20cm. The conductive paint raw material was diluted with deionized water at a mass ratio of conductive paint raw material to deionized water of 1:0.6. The resulting conductive paint had a viscosity of 850mPa·s and a sheet resistance of 200Ω / sq / mil at room temperature.

[0051] The resistive film was cured at a temperature of 60℃ for 15 minutes, and the resistance value was determined to be 100Ω / sq using the four-probe method.

[0052] S3: Fabrication of a transversely loaded resistive film absorbing honeycomb structure

[0053] PMI foam sheets coated with conductive paint were evenly divided into thinner sheets, each 1 mm thick. First, PMI foam sheets coated with conductive paint were flatly pressed onto the foam sheets. Then, the remaining sheets were flatly pressed into an aramid paper honeycomb with a side length of 3 mm, a wall thickness of 0.06 mm, and a height of 30 mm. By pressing layer by layer, a wave-absorbing honeycomb structure with a transversely loaded resistive film was obtained. The structure was stable and its performance was basically consistent with the simulation.

[0054] Example 2

[0055] The microwave absorbing honeycomb structure 1 with a transversely loaded resistive film provided in Embodiment 2 has a hexagonal honeycomb substrate 111 with a side length L=3mm, a wall thickness D=0.13mm, and a height W=30mm. The real part of the dielectric constant of the inner wall of the hexagonal honeycomb substrate 111 is set to 30, and the dielectric tangent is set to 0.4 to simulate the honeycomb state of impregnated microwave absorbing slurry. A transverse resistive film 112 is loaded inside the microwave absorbing honeycomb structure (absorbing unit 11). Specifically, the plane of the transverse resistive film 112 is perpendicular to the depth direction of the honeycomb holes, and the transverse resistive film 112 covers all the microwave absorbing honeycomb holes. The distance i between the transverse resistive film 112 with a resistance r of 100Ω / sq and the metal reflector 2 varies from -1 to 30mm (excluding 0). When i=-1mm, the transverse resistive film 112 is placed below the metal reflector 2, and the reflectivity is not affected by the resistive film loading. Figure 4 The reflectance curves show that only one layer of transverse resistive film 112 is needed to significantly change the reflectance compared to the original honeycomb structure. Specifically, when i=10mm, the reflectance is lowest in the 2-4GHz range. Therefore, by fixing i=10mm and varying the resistive film resistance r from 0~700Ω / sq (excluding 0), the reflectance can be obtained from... Figure 5The reflectivity curves show that in the 2-4 GHz range, reflectivity first decreases and then increases with increasing r value, reaching its lowest point at r = 200 Ω / sq. Furthermore, while increasing the resistance r to 500 Ω / sq still has a modulating effect on reflectivity, the degree of change is small.

[0056] The fabrication method for this transversely loaded resistive film-based absorbing honeycomb structure design is as follows:

[0057] S1: Preparation of poly(meth)acrylimide foam board

[0058] Weigh out 50g of methacrylic acid, 50g of methacrylonitrile, 2g of initiator azobisisobutyronitrile, 10g of foaming agent methanol, 2g of crosslinking agent calcium oxide, and 1g of nucleating agent titanium dioxide by weight and add them to the reaction vessel. Stir mechanically for 3 hours to obtain a material mixture. Then, pour the obtained material mixture into a mold, heat it to 45°C in a water bath, polymerize for 105 hours, and then perform post-treatment in an oven, heating it to 200°C for foaming for 4 hours.

[0059] S2: Conductive paint is sprayed onto the surface of poly(meth)acrylimide foam board.

[0060] The foamed PMI foam board was cut into 10mm thick slices according to simulation results. Conductive paint was sprayed onto the surface of the slices using a spray gun to form a resistive film. The nozzle size was 0.5mm, and the distance between the nozzle and the carrier was 20cm. The conductive paint raw material was diluted with deionized water at a mass ratio of conductive paint raw material to deionized water of 1:0.6. The resulting conductive paint had a viscosity of 850mPa·s and a sheet resistance of 200Ω / sq / mil at room temperature.

[0061] The resistive film was cured at a temperature of 50°C for 20 minutes, and the resistance value was determined to be 200 Ω / sq using the four-probe method.

[0062] S3: Absorbing Cell Fabrication

[0063] 500g of epoxy resin adhesive, 50g of conductive carbon black absorbent, 50g of epoxy non-reactive diluent, and 150g of modified fatty amine curing agent were mixed according to the specified ratio to prepare a microwave absorbing adhesive. A portion of the microwave absorbing adhesive was taken out and cured in an oven at 160℃ for 2 hours. Coaxial testing was performed to determine that the average real part of the dielectric constant of the cured microwave absorbing adhesive was 30, and the average dielectric tangent was 0.4.

[0064] A hexagonal aramid paper honeycomb with a side length of 3mm, a wall thickness of 0.06mm, and a height of 30mm was repeatedly immersed in the prepared microwave absorbing adhesive solution, with an immersion thickness of 0.035mm. It was then cured in an oven at 160℃ for 2 hours to obtain the microwave absorbing honeycomb. In this step, after immersing 0.035mm on both sides of the hexagonal aramid paper honeycomb wall, the thickness is 0.13mm.

[0065] S4: Fabrication of a transversely loaded resistive film absorbing honeycomb structure

[0066] PMI foam sheets coated with conductive paint are evenly divided into thinner sheets with a thickness of 2mm. First, PMI foam sheets coated with conductive paint are flatly pressed, and then the remaining sheets are flatly pressed into the absorbing honeycomb layer by layer. By layering, an absorbing honeycomb structure with a transversely loaded resistive film is obtained. The structure is stable and the performance is basically consistent with the simulation.

[0067] Example 3

[0068] The microwave absorbing honeycomb structure 1 with a transversely loaded resistive film provided in this embodiment 3 has a hexagonal honeycomb substrate 111 with a side length L=3mm, a wall thickness D=0.13mm, and a height W=30mm. The real part of the dielectric constant of the inner wall of the hexagonal honeycomb substrate 111 is set to 30, and the dielectric tangent is set to 0.4 to simulate the honeycomb state of the impregnated microwave absorbing slurry. A transverse resistive film 112 is loaded inside the microwave absorbing honeycomb structure (absorbing unit 11). Specifically, the plane of the transverse resistive film 112 is perpendicular to the depth direction of the honeycomb holes, and the transverse resistive film 112 covers all the microwave absorbing honeycomb holes. The distance i between the transverse resistive film 112 with a resistance r of 100Ω / sq and the metal reflector 2 is 10mm, and the distance i between the transverse resistive film 112 with a resistance r of 200Ω / sq and the metal reflector 2 is 20mm. In this embodiment, two transverse resistive films 112 are loaded, which are... Figure 6 The reflectance curves show that the reflectance of the absorbing cell with two transverse resistive films 112 loaded is less than that of the original absorbing cell at 2-4 GHz.

[0069] The fabrication method for this transversely loaded resistive film-based absorbing honeycomb structure design is as follows:

[0070] S1: Preparation of poly(meth)acrylimide foam board

[0071] Weigh out 70g of methacrylic acid, 70g of methacrylonitrile, 2.2g of initiator azobisisobutyronitrile, 16g of foaming agent methanol, 5g of crosslinking agent calcium oxide, and 3g of nucleating agent titanium dioxide by weight and add them to the reaction vessel. Stir mechanically for 4 hours to obtain a material mixture. Then pour the obtained material mixture into a mold, heat it to 45℃ in a water bath, polymerize for 105 hours, and then perform post-treatment in an oven, heating it to 240℃ for foaming for 8 hours.

[0072] S2: Conductive paint is sprayed onto the surface of poly(meth)acrylimide foam board.

[0073] The foamed PMI foam board was cut into two 10mm thick slices based on simulation results. Conductive paint was sprayed onto the surface of the two slices using a spray gun to form a resistive film. The nozzle size was 0.5mm, and the distance between the nozzle and the carrier was 20cm. The conductive paint raw material was diluted with deionized water at a mass ratio of conductive paint raw material to deionized water of 1:0.6. The resulting conductive paint had a viscosity of 850mPa·s and a sheet resistance of 200Ω / sq / mil at room temperature.

[0074] The resistive film was cured at a temperature of 70℃ for 30 minutes. The resistance values ​​of the resistive film on the upper surface of the two films were determined to be 100Ω / sq and 200Ω / sq, respectively, using the four-probe method.

[0075] S3: Absorbing Cell Fabrication

[0076] 500g of epoxy resin adhesive, 50g of conductive carbon black absorbent, 50g of epoxy non-reactive diluent, and 150g of modified fatty amine curing agent were mixed according to the specified ratio to prepare a microwave absorbing adhesive. A portion of the microwave absorbing adhesive was taken out and cured in an oven at 160℃ for 2 hours. Coaxial testing was performed to determine that the average real part of the dielectric constant of the cured microwave absorbing adhesive was 30, and the average dielectric tangent was 0.4.

[0077] A hexagonal aramid paper honeycomb with a side length of 3mm, a wall thickness of 0.06mm, and a height of 30mm was repeatedly immersed in the prepared microwave absorbing adhesive liquid, with an immersion thickness of 0.035mm. It was then cured in an oven at a temperature of 160℃ for 2 hours to obtain the microwave absorbing honeycomb.

[0078] S4: Fabrication of a transversely loaded resistive film absorbing honeycomb structure

[0079] PMI foam sheets coated with conductive paint were evenly divided into thinner sheets, each 2 mm thick. First, a PMI foam sheet with conductive paint (resistance r = 200 Ω / sq) was flattened and pressed into the absorbing honeycomb layer by layer. Then, another PMI foam sheet with conductive paint (resistance r = 100 Ω / sq) was flattened and pressed into the absorbing honeycomb layer by layer. This process was repeated to obtain an absorbing honeycomb structure with two transversely loaded resistive films. The structure was stable, and its performance was basically consistent with the simulation.

[0080] Example 4

[0081] The microwave absorbing honeycomb structure 1 with a transversely loaded resistive film provided in Embodiment 4 has a hexagonal honeycomb substrate 111 with a side length L=3mm, a wall thickness D=0.13mm, and a height W=30mm. The real part of the dielectric constant of the inner wall of the hexagonal honeycomb substrate 111 is set to 55, and the dielectric tangent is set to 0.5 to simulate the honeycomb state of impregnated microwave absorbing slurry. A transverse resistive film 112 is loaded inside the microwave absorbing honeycomb structure (absorbing unit 11). Specifically, the plane of the transverse resistive film 112 is perpendicular to the depth direction of the honeycomb holes, and the transverse resistive film 112 covers all the microwave absorbing honeycomb holes. The distance i between the transverse resistive film 112 with a resistance r of 100Ω / sq and the metal reflector 2 varies from -1 to 30mm (excluding 0). When i=-1mm, the transverse resistive film 112 is placed below the metal reflector 2, and the reflectivity is not affected by the resistive film loading. Figure 7 The reflectance curves show that only one layer of transverse resistive film 112 is needed to significantly change the reflectance compared to the original honeycomb structure. Specifically, when i=8mm, the reflectance is lowest at 2GHz, ensuring the widest absorption bandwidth of less than -10dB. Therefore, by fixing i=8mm and varying the resistive film resistance r from 0 to 700Ω / sq (excluding 0), the reflectance can be obtained from... Figure 8 The reflectivity curves show that in the 2-4 GHz range, reflectivity first decreases and then increases with increasing r value, reaching its lowest point at r = 100 Ω / sq. However, the absorption bandwidth below -10 dB is widest at r = 200 Ω / sq. Furthermore, while increasing the resistance r to 400 Ω / sq still has a modulating effect on reflectivity, the degree of change is small.

[0082] The fabrication method for this transversely loaded resistive film-based absorbing honeycomb structure design is as follows:

[0083] S1: Preparation of poly(meth)acrylimide foam board

[0084] Weigh out 50g of methacrylic acid, 50g of methacrylonitrile, 2g of initiator azobisisobutyronitrile, 10g of foaming agent methanol, 2g of crosslinking agent calcium oxide, and 1g of nucleating agent titanium dioxide by weight and add them to the reaction vessel. Stir mechanically for 3 hours to obtain a material mixture. Then, pour the obtained material mixture into a mold, heat it to 45°C in a water bath, polymerize for 105 hours, and then perform post-treatment in an oven, heating it to 200°C for foaming for 4 hours.

[0085] S2: Conductive paint is sprayed onto the surface of poly(meth)acrylimide foam board.

[0086] The foamed PMI foam board was cut into 8mm thick sheets according to simulation results. Conductive paint was sprayed onto the surface of the sheets using a spray gun to form a resistive film. The nozzle size was 0.5mm and the distance between the nozzle and the carrier was 20cm. The conductive paint raw material was diluted with deionized water at a mass ratio of conductive paint raw material to deionized water of 1:0.6. The resulting conductive paint had a viscosity of 850mPa·s and a sheet resistance of 200Ω / sq / mil at room temperature.

[0087] The resistive film was cured at a temperature of 50°C for 20 minutes, and the resistance value was determined to be 200 Ω / sq using the four-probe method.

[0088] S3: Absorbing Cell Fabrication

[0089] 500g of epoxy resin adhesive, 150g of conductive carbon black absorbent, 100g of epoxy non-reactive diluent, and 200g of modified fatty amine curing agent were mixed according to the specified ratio to prepare a microwave absorbing adhesive. A portion of the microwave absorbing adhesive was taken out and cured in an oven at 160℃ for 2 hours. Coaxial testing was performed to determine that the average real part of the dielectric constant of the cured microwave absorbing adhesive was 55 and the average dielectric tangent was 0.5.

[0090] A hexagonal aramid paper honeycomb with a side length of 3mm, a wall thickness of 0.06mm, and a height of 30mm was repeatedly immersed in the prepared microwave absorbing adhesive liquid, with an immersion thickness of 0.035mm. It was then cured in an oven at a temperature of 160℃ for 2 hours to obtain the microwave absorbing honeycomb.

[0091] S4: Fabrication of a transversely loaded resistive film absorbing honeycomb structure

[0092] PMI foam sheets coated with conductive paint are evenly divided into thinner sheets with a thickness of 2mm. First, PMI foam sheets coated with conductive paint are flatly pressed, and then the remaining sheets are flatly pressed into the absorbing honeycomb layer by layer. By layering, an absorbing honeycomb structure with a transversely loaded resistive film is obtained. The structure is stable and the performance is basically consistent with the simulation.

[0093] Higher dielectric absorbing honeycomb requires higher dielectric absorbing adhesive, which in turn requires more conductive carbon black absorber. Through further research, the inventors unexpectedly discovered that impregnation with this high dielectric absorbing adhesive is prone to coating quality degradation, failing to achieve the theoretical simulation state. Therefore, a dielectric constant with a real part greater than 55 will be subject to process limitations.

[0094] Simulation analysis of Examples 1 to 4 shows that the absorbing honeycomb structure with a transverse resistive film 112 provided in this example can effectively control reflectivity when the distance between the transverse resistive film 112 and the metal reflector 2 is i (0 < i ≤ W) and the resistance of the transverse resistive film 112 is rΩ / sq (0 < r ≤ 600). The number of transverse resistive films 112 that can be loaded is greater than or equal to one. Example 1 shows that only one transverse resistive film is needed to impart absorbing performance to the white honeycomb, i.e., a reflectivity band of less than -10dB in the 2-18GHz range. Example 2 shows that loading one transverse resistive film can optimize the lower-frequency reflectivity of the absorbing honeycomb, i.e., a lower reflectivity value. Example 3 shows that adding an additional transverse resistive film (a total of two transverse resistive films) on top of Example 2 can further optimize the low-frequency reflectivity. Example 4 shows that the effect of adding a transverse resistive film to honeycomb substrates with different electromagnetic parameters on reflectivity control is also applicable to high-dielectric absorbing honeycombs.

[0095] Based on the same inventive concept, this utility model embodiment also provides an anti-interference device, the outer surface of which is attached with the aforementioned transversely loaded resistive film absorbing honeycomb structure. The beneficial effects of this anti-interference device can be referred to the relevant description of the transversely loaded resistive film absorbing honeycomb structure, which will not be repeated here.

[0096] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. This disclosure is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims. Thus, if these modifications and variations of this utility model fall within the scope of the claims of this utility model and their equivalents, this utility model is also intended to include these modifications and variations.

Claims

1. A microwave absorbing honeycomb structure with a laterally loaded resistive film, characterized in that, include: Multiple absorbing units arranged sequentially on the same plane; Each absorbing unit includes a hexagonal honeycomb substrate and at least one transverse resistive film located within the hexagonal honeycomb substrate, the transverse resistive film being perpendicular to the central axis of the hexagonal honeycomb substrate.

2. The microwave absorbing honeycomb structure with a laterally loaded resistive film according to claim 1, characterized in that, The microwave absorbing unit also includes foam located at the openings of the transverse resistive film and the hexagonal honeycomb substrate.

3. The microwave absorbing honeycomb structure with a laterally loaded resistive film according to claim 1 or 2, characterized in that, The position of the transverse resistive film within the hexagonal honeycomb matrix is ​​adjustable, and the resistance of the transverse resistive film is not higher than 600Ω / sq.

4. The microwave absorbing honeycomb structure with a laterally loaded resistive film according to claim 3, characterized in that, The hexagonal honeycomb substrate has a side length of 3mm, a wall thickness of 0.06mm or 0.13mm, and a height of 30mm.

5. The microwave absorbing honeycomb structure with a laterally loaded resistive film according to claim 4, characterized in that, The real part of the dielectric constant of the inner wall of the hexagonal honeycomb substrate is 2.3~55, and the dielectric tangent is 0.001~0.

5.

6. An anti-interference device, characterized in that, The outer surface of the anti-interference device is attached with a wave-absorbing honeycomb structure of a transversely loaded resistive film as described in any one of claims 1 to 5.

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