Electromagnetic-thermal compatible wave-absorbing material

Abstract

The present application relates to the field of radar stealth, specifically to an electromagnetic-thermal compatible wave-absorbing material and a design method thereof.The present application controls the energy loss density at different positions of the overall wave-absorbing material by performing gradient gradual design of electromagnetic parameters of n kinds of wave-absorbing materials from a single wave-absorbing material, so that the internal heating and heat dissipation of the wave-absorbing material are more uniform, and the overall temperature distribution is more uniform, so that the overall stealth material has a lower internal temperature of the wave-absorbing material under the premise of ensuring electromagnetic performance, and simultaneously meets the high-efficiency electromagnetic wave absorption capacity and good heat dissipation capacity, effectively deals with the serious internal heating problem of the wave-absorbing material of the structure stealth material under high-power electromagnetic wave irradiation, to ensure the normal work of the stealth material and the safe operation of the equipment.The present application has great advantages in the thermal management of the stealth wave-absorbing material due to its simple structure and easy implementation.

Description

Technical Field

[0001] This invention relates to the field of radar stealth, specifically to an electromagnetically and thermally compatible radar absorbing material and its design method. Background Technology

[0002] In modern high-tech warfare, enemy radar systems and various weapon systems make the battlefield extremely dangerous. Radar stealth technology plays a crucial role in modern warfare, reducing the radar detection range of military targets, improving their concealment, and serving as a key means for troops to enhance combat capabilities, increase survivability, and ensure sustained operations.

[0003] Radar-absorbing materials are a key component of radar stealth technology. Their main working principle is to absorb electromagnetic waves and convert their energy into heat, thus achieving stealth for aircraft. During service, when the antenna's power density reaches tens of kilowatts per square meter, the radar-absorbing material absorbs electromagnetic energy and dissipates a large amount of heat, causing its temperature to rise rapidly. The poor heat dissipation performance of the material at this point can significantly impact flight performance and may even lead to structural damage or burn-out. Therefore, the design of radar-absorbing materials must consider not only their excellent electromagnetic wave absorption performance but also the management of the heat they generate to ensure their proper functioning and the safe operation of the aircraft.

[0004] In existing technologies, researchers have proposed methods such as adding thermally conductive materials, using multiple composite materials, and adding thermal insulation layers to design thermally conductive microwave absorbing materials. For example, CN202211450939 describes a broadband microwave absorbing and thermally conductive periodic structure. By adding thermally conductive materials through the vias, a macroscopic thermal conductive path is formed in the thickness direction of the microwave absorbing material, increasing the equivalent thermal conductivity and improving heat dissipation. However, this structure has the disadvantage of adding additional thermally conductive materials, increasing the complexity of the microwave absorbing material design. CN201821299818 describes a composite structure of heat dissipation and microwave absorbing materials, using a composite structure of carbon fiber microwave absorbing composite material layers, polymer microwave absorbing composite material layers, and nano-microwave absorbing composite material layers. This structure efficiently conducts heat but does not consider microwave absorption performance. CN201811474249 describes an ultra-wideband microwave absorbing structure and its preparation method that combines temperature resistance and mechanical properties. This structure uses a ceramic-based high-temperature resistant composite microwave absorbing material to achieve effective absorption and thermal insulation of high-frequency electromagnetic waves. The microwave absorbing layer and the thermal insulation layer are separated, and the number of microwave absorbing material layers is large, resulting in a complex structure. While these designs improved the thermal conductivity and temperature resistance of the absorbing materials, none of them took into account the electromagnetic-thermal compatibility design of the absorbing materials. Summary of the Invention

[0005] To address the aforementioned problems and shortcomings, and to solve the issue of a sharp temperature rise in absorbing materials after efficiently absorbing electromagnetic wave energy, this invention provides an electromagnetically and thermally compatible absorbing material and its design method. By implementing a gradient design for the absorbing material and utilizing the gradient of the material's electromagnetic parameters, the energy loss density at different locations of the overall absorbing material can be controlled. This approach ensures that while maintaining the material's absorbing performance, the heat distribution of the absorbing material is more uniform under high-power antenna operating conditions, resulting in a lower overall maximum temperature for the material.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An electromagnetically and thermally compatible microwave absorbing material is used as a structural stealth material. The carrier is coated with n kinds of microwave absorbing materials, where n≥2. The n kinds of microwave absorbing materials are divided into n segments according to the gradient of electromagnetic parameters from the height of the carrier and coated sequentially.

[0008] A design method for an electromagnetically and thermally compatible microwave absorbing material, the specific steps of which are as follows:

[0009] Step 1: Preliminary gradient design of absorbing material:

[0010] Instead of using a single type of absorbing material with the same coating height h for structural stealth, n types of absorbing materials are used, arranged in n segments according to the magnitude of their electromagnetic parameters (dielectric constant, permeability); corresponding to h = h1 + h2...h n .

[0011] Step 2, Modeling and Optimization:

[0012] Modeling of the n gradient-varying absorbing materials initially determined in step 1 was performed using electromagnetic simulation software and multiphysics simulation software. Based on the established models, h1, h2…h were adjusted using simulation software. n The size and types of n absorbing materials were further optimized and confirmed to achieve the final electromagnetic-thermal compatible absorbing material parameters.

[0013] Electromagnetic simulation and performance evaluation of absorbing materials: Electromagnetic performance (reflectivity, RCS) of the model established in step 2 was simulated using electromagnetic simulation software. The broadband / wide-angle electromagnetic performance of single absorbing materials and gradient absorbing materials was evaluated. The comparison showed that the electrical performance of gradient absorbing materials is better than that of single absorbing materials.

[0014] Thermal simulation and performance evaluation of microwave absorbing materials: The thermal performance (temperature field distribution) of the model established in step 2 was simulated using multiphysics simulation software. The single-frequency thermal performance of single microwave absorbing materials and gradient microwave absorbing materials was evaluated. The comparison showed that the maximum temperature of gradient microwave absorbing materials was much lower than that of single microwave absorbing materials, and the thermal performance of gradient microwave absorbing materials was far superior to that of single microwave absorbing materials.

[0015] In summary, this invention addresses the severe internal heating problem of the absorbing material in stealth materials under high-power electromagnetic wave irradiation. By designing a gradient of electromagnetic parameters for n different absorbing materials within a single material, the overall stealth material maintains its electromagnetic performance while keeping the internal temperature of the absorbing material lower. This simultaneously satisfies both efficient electromagnetic wave absorption and good heat dissipation, ensuring the normal operation of the stealth material and the safe operation of the equipment. Furthermore, this invention has a simple structure, is easy to implement, and offers significant advantages in the thermal management of stealth absorbing materials. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of Example 1.

[0017] Figure 2 The reflectance curve is shown in Example 1.

[0018] Figure 3 This is the temperature field distribution of Example 1.

[0019] Figure 4 This is a schematic diagram of the structure of Example 2.

[0020] Figure 5 The RCS curve is for Example 2.

[0021] Figure 6 This is the temperature field distribution of Example 2. Detailed Implementation

[0022] To more clearly illustrate the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0023] In the following examples, n=3. Example 1 uses a honeycomb absorbing material with h=25mm, which is divided into a single absorbing material (Model-1) and a gradient absorbing material (Model-2), as follows. Figure 1 As shown. Example 2 involves loading a microwave absorbing material onto an ellipsoidal carrier. The ellipsoid has a major axis radius of 150 mm and a minor axis radius of 75 mm. It is divided into two types: loading a single microwave absorbing material (Model-3) and loading a gradient-varying microwave absorbing material (Model-4), as shown. Figure 4 As shown, the gradient change begins at the carrier end, where the electromagnetic parameters gradually decrease.

[0024] Example 1

[0025] Step 1: Absorbing Material Design and Modeling: A three-layer gradient design (Model-2) is implemented for the honeycomb absorbing material, consisting of material1, material2, and material3. Material1 is used for the single absorbing material (Model-1). Models of the single absorbing material (Model-1) and the gradient-changing absorbing material (Model-2) are created using the electromagnetic simulation software CST and the multiphysics simulation software Comsol. Both Model-1 and Model-2 are honeycomb absorbing materials with a total height of h = 25 mm. The heights of the three honeycomb absorbing materials in Model-2 are h1 = 16 mm, h2 = 4.8 mm, and h3 = 4.2 mm, where h = h1 + h2 + h3.

[0026] Step 2: Electromagnetic simulation and performance evaluation of the absorbing material: Broadband (2-18GHz) reflectivity simulation was performed on Model-1 and Model-2 established in Step 1 using the electromagnetic simulation software CST. The reflectivity results are as follows: Figure 2 As shown, the overall reflectivity of Model-1 and Model-2 is not significantly different in the broadband 2-18GHz range; at 10GHz, the reflectivity of Model-1 and Model-2 are -11.9dB and -13dB, respectively, indicating that Model-1 has superior absorption performance.

[0027] Step 3: Thermal simulation and performance evaluation of the absorbing material: The thermal performance of Model-1 and Model-2 established in Step 1 was simulated at a frequency of 10 GHz using the multiphysics simulation software Comsol. The temperature field distribution is as follows: Figure 3 As shown, the highest temperature of Model-1 is 203 degrees Celsius, while the highest temperature of Model-2 is 120 degrees Celsius. The comparison shows that Model-2 has superior thermal performance.

[0028] Example 2

[0029] Step 1: Absorbing Material Design and Modeling: A three-layer gradient design (Model-4) is implemented for the absorbing material loaded on the upper half of the metal ellipsoidal carrier. The three layers of absorbing material are material1, material2, and material3. Material1 is used for loading a single absorbing material (Model-3). Models of the single absorbing material (Model-3) and the gradient-changing absorbing material (Model-4) are modeled using the electromagnetic simulation software CST and the multiphysics simulation software Comsol. Both Model-3 and Model-4 involve loading absorbing materials onto a metal ellipsoidal carrier. The major axis radius of the ellipsoid is 150 mm, and the minor axis radius is 75 mm. The region where the absorbing material is loaded is the upper half of the ellipsoidal carrier. The total height of the loaded material in both Model-3 and Model-4 is h = 150 mm. The heights of the three honeycomb-type absorbing materials in Model-4 are h1 = 46 mm, h2 = 49 mm, and h3 = 55 mm, where h = h1 + h2 + h3.

[0030] Step 2: Electromagnetic simulation and performance evaluation of the absorbing material: Using the electromagnetic simulation software Feko, wide-angle (incident angle of -45° to 45°) RCS (Radar Cross Section) simulations were performed on models-3 and-4 established in Step 1. The RCS results under the two polarizations are as follows: Figure 5 As shown, the overall RCS of Model-3 and Model-4 are not significantly different at incident angles of -45° to 45°. At a positive incident azimuth angle of 0°, under horizontal polarization, the RCS of Model-3 and Model-4 are -34.6 dBsm and -42.5 dBsm, respectively; under vertical polarization, the RCS of Model-3 and Model-4 are -33.6 dBsm and -38.3 dBsm, respectively. The comparison shows that Model-2 has superior stealth performance.

[0031] Step 3: Thermal simulation and performance evaluation of the absorbing material: The thermal performance of models-3 and-4 established in Step 1 was simulated at a frequency of 10 GHz using the multiphysics simulation software Comsol. The temperature field distribution is as follows: Figure 6 As shown, the highest temperature of Model-3 is 205 degrees Celsius, while the highest temperature of Model-4 is 130 degrees Celsius. The comparison shows that Model-4 has superior thermal performance.

[0032] As can be seen from the above embodiments, the electromagnetic performance of the n-gradient absorbing materials provided by this invention is superior to that of a single absorbing material. The gradient-gradient absorbing materials also exhibit lower internal temperatures and superior thermal performance. This invention designs a gradient of electromagnetic parameters for n different absorbing materials from a single material, controlling the energy loss density at different locations within the overall absorbing material. This results in more uniform internal heating and cooling, and a more uniform overall temperature distribution. Consequently, the stealth material maintains its electromagnetic performance while maintaining a lower internal temperature, simultaneously satisfying both efficient electromagnetic wave absorption and good heat dissipation. This effectively addresses the severe internal heating problem of the absorbing material in stealth structures under high-power electromagnetic wave irradiation, ensuring the normal operation of the stealth material and the safe operation of the equipment. Furthermore, this invention has a simple structure, is easy to implement, and offers significant advantages in the thermal management of stealth absorbing materials.

Claims

1. An electromagnetically and thermally compatible absorbing material, used as a structural stealth material, characterized in that: The structural stealth material carrier is coated with n types of absorbing materials, where n is greater than 2. The n types of absorbing materials are divided into n segments and coated sequentially according to the gradient of electromagnetic parameters from the height of the carrier. The electromagnetic parameters are dielectric constant and magnetic permeability. By utilizing the gradient of the electromagnetic parameters of the materials, the energy loss density at different locations of the overall absorbing material is controlled. While taking into account the absorbing performance of the materials, the heat distribution of the absorbing materials under the working conditions of high-power antennas is more uniform, and the overall maximum temperature of the materials is lower. The design method for electromagnetically and thermally compatible absorbing materials involves the following steps: Step 1: Preliminary gradient design of absorbing material: Instead of using a single type of absorbing material with the same coating height h for structural stealth, n types of absorbing materials are used, arranged in n segments according to the magnitude of their electromagnetic parameters in a gradient manner; corresponding to h = h1 + h2...h n ; Step 2, Modeling and Optimization: Model the n gradient-varying absorbing materials initially determined in step 1 using electromagnetic simulation software and multiphysics simulation software; adjust h1, h2...h according to the established model using simulation software. n The size and types of n absorbing materials were further optimized and confirmed to achieve the final electromagnetic-thermal compatible absorbing material parameters.

2. The electromagnetically and thermally compatible absorbing material as described in claim 1, characterized in that: The gradient change begins at the carrier end, where the electromagnetic parameters gradually decrease.

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