High-temperature-resistant intelligent stealth material structure

Abstract

The invention discloses a high-temperature-resistant intelligent stealth material structure which comprises a high-temperature-resistant uniform wave-transparent material and further comprises an intelligent stealth structure layer constructed in a vertical integration mode, and the intelligent stealth structure layer comprises an electromagnetic environment induction module, an execution unit layer, a drive circuit layer and a control circuit layer. The intelligent stealth structure layer adopts a multi-layer collaborative architecture to realize dynamic perception-decision-execution control of an electromagnetic environment, an electromagnetic induction module captures incident wave frequency-polarization parameters in real time, generates an optimal coding sequence through the control circuit layer and converts the optimal coding sequence into a unit bias voltage matrix; the signal is loaded to the execution unit layer after being driven by the driving circuit layer; and each unit of the execution unit layer changes the resonance state according to the voltage instruction. Therefore, the problems of intelligent stealth structure and algorithm design, high-temperature-resistant adaptability and the like are solved, and support is provided for broadband dynamic stealth of aerospace crafts in a high-temperature environment.

Description

Technical Field

[0001] The present invention relates to the technical field of stealth materials, and in particular to a high-temperature resistant intelligent stealth material structure. Background Art

[0002] High-temperature-resistant intelligent stealth materials are advanced materials that can maintain their stealth properties in high-temperature environments and have significant potential for military and industrial applications. These materials have broad application prospects in military, aerospace, and industrial fields, such as stealth fighters, missiles, ships, spacecraft thermal protection systems, reentry vehicles, and high-temperature industrial equipment and energy systems.

[0003] The development of stealth technology initially stemmed from military needs, with the primary goal of rendering military equipment (such as aircraft and ships) invisible to enemy radar and infrared detection systems. Early stealth technology relied primarily on absorbing materials and electromagnetic wave scattering techniques. However, with the increasing complexity of modern battlefield environments and advances in detection technology, the limitations of traditional stealth materials have gradually become apparent. In particular, the issue of stealth performance and stability in extreme environments (such as high temperatures and high pressures) requires urgent resolution.

[0004] In the 21st century, breakthroughs in high-temperature resistant and intelligent materials technologies, particularly the development of ultra-high-temperature ceramics, carbon-based composites, and intelligent responsive materials, have made it possible to achieve effective stealth in high-temperature environments. These materials not only exhibit excellent high-temperature resistance but also utilize intelligent regulation mechanisms to adaptively adjust their electromagnetic properties to environmental changes, significantly enhancing stealth effectiveness and its scope of application. As aircraft speeds continue to increase, operating environments become increasingly harsh, placing ever-stricter demands on the performance of stealth materials. Summary of the Invention

[0005] The present invention provides a high-temperature resistant intelligent stealth material structure. Its purpose is to address the limitations of current radar stealth technology in high-temperature resistance, frequency band, and performance. By adopting simulation design, high-temperature testing and other methods, the paper conducts research on new stealth technology based on intelligent electromagnetic control, solves the difficulties in intelligent stealth structure and algorithm design, high-temperature adaptability, and provides support for broadband dynamic stealth of aerospace vehicles in high-temperature environments.

[0006] First, a high-temperature resistant intelligent stealth material structure is provided, including a high-temperature resistant uniform wave-transparent material, and an intelligent stealth structure layer constructed in a vertically integrated manner, wherein the intelligent stealth structure layer includes an electromagnetic environment sensing module, an execution unit layer, a drive circuit layer, and a control circuit layer; the intelligent stealth structure layer adopts a multi-layer collaborative architecture to realize dynamic perception-decision-making-execution control of the electromagnetic environment, wherein the electromagnetic induction module captures the frequency-polarization parameters of the incident wave in real time, generates the optimal coding sequence through the control circuit layer and converts it into a unit bias voltage matrix, which is driven by the drive circuit layer and loaded to the execution unit layer; each unit in the execution unit layer changes the resonance state according to the voltage instruction.

[0007] In combination with the first aspect, in certain implementations of the first aspect, the high-temperature resistant uniform wave-transmitting material uses a two-dimensional orthogonal woven quartz fiber fabric as a reinforcement, a high-purity quartz ceramic or a nitride ceramic as a matrix, and prepares a layered structure composite material through an impregnation-hot pressing and sintering composite process.

[0008] In conjunction with the first aspect, in certain implementations of the first aspect, the high-temperature resistant uniform wave-transmitting material satisfies at least one of the following:

[0009] The reinforcement is a two-dimensional orthogonal quartz fiber fabric with a warp density of 16±0.5 bundles / cm and a weft density of 12±0.5 bundles / cm. The fiber monofilament diameter is 9±0.5μm and is surface treated with a silane coupling agent to form a chemical bonding interface with the matrix.

[0010] The substrate is made of high-purity quartz ceramics with SiO2 content ≥99.9wt% or nitride ceramics with Si3N4 content ≥95wt%, and the thickness of the substrate layer is controlled in the range of 0.2-0.5mm;

[0011] The high-temperature resistant, uniform, and wave-transparent material adopts a three-step impregnation-lamination-hot-pressing sintering process: first, the pretreated quartz fiber fabric is vacuum-impregnated in the matrix slurry for 30 minutes, and the solid content of the slurry is controlled at 45-50 vol%. Then, the layers are stacked with a pre-pressure of 0.5 MPa. After every 5 layers, a pressure of 2 MPa is applied and maintained for 10 minutes. Finally, gradient sintering is carried out under argon protection, and the temperature is raised to 1350°C (quartz-based) or 1650°C (nitride-based) at a rate of 5°C / min. After holding for 2 hours, the material is cooled in the furnace.

[0012] In combination with the first aspect, in certain implementations of the first aspect, the electromagnetic environment sensing module uses a composite sensor network consisting of a microstrip antenna array and a loop-open antenna, which is grid-distributed on the surface of a high-temperature resistant and wave-transparent substrate with a spacing of 0.5 cm; the microstrip antenna captures the electric field component in the 6-12.5 GHz frequency band, and the loop-open antenna detects the magnetic field component, and a dual-polarized digital signal is formed after processing by a low-noise amplifier (gain > 40 dB) and a bandpass filter.

[0013] In combination with the first aspect, in certain implementations of the first aspect, the control circuit layer includes a high-performance digital signal processor DSP, a field programmable gate array FPGA, a data bus and a wireless communication module; the wireless communication module is connected to the electromagnetic environment sensing module, and after using a bandpass filter to eliminate out-of-band noise, it is transmitted to the DSP via the data bus to execute an environmental feature extraction algorithm based on a deep residual network, while the FPGA parallel processes the execution unit layer to generate control instructions.

[0014] In conjunction with the first aspect, in some implementations of the first aspect, the control circuit layer further includes at least one of the following:

[0015] Power management module, the power management module is equipped with a three-stage voltage stabilization circuit, uses silicon carbide power devices to achieve 94% conversion efficiency, and integrates a triple protection mechanism of overvoltage / undervoltage / short circuit;

[0016] The heat dissipation module adopts a graphene-aluminum nitride composite substrate and combines it with a microchannel liquid cooling structure to ensure that the chip junction temperature is ≤85°C in a high temperature environment.

[0017] In combination with the first aspect, in certain implementations of the first aspect, the driving circuit layer adopts a three-stage current amplification architecture, which includes a pre-amplifier module, an intermediate amplification module and a final drive module; the pre-amplifier module uses a low-noise operational amplifier to perform primary amplification of the signal output by the control circuit layer, and its input stage is configured with a differential circuit with a common-mode rejection ratio >120dB to eliminate electromagnetic interference; the intermediate amplification module uses GaN HEMT devices to construct a push-pull power amplifier circuit, and increases the voltage to 0-50V through a negative feedback compensation network; the final drive module uses an LDMOS power tube array to achieve 100V high-voltage output, and each drive unit is equipped with an independent overcurrent protection circuit.

[0018] In combination with the first aspect, in certain implementations of the first aspect, the driving circuit layer uses a multi-layer ceramic substrate with an aluminum oxide content ≥96% for three-dimensional integration, uses a gold wire bonding process to connect the functional modules, and configures a copper pillar array at the output end to realize parallel transmission of signals of the execution unit layer.

[0019] In conjunction with the first aspect, in certain implementations of the first aspect, the execution unit layer includes a periodically arranged two-dimensional metamaterial array, and the multiple coding patterns of the two-dimensional metamaterial array are used to respectively generate multiple beam scattering patterns under plane wave illumination;

[0020] The unit structure of the execution unit layer includes a vertically stacked double split-ring resonator (SRR) and a metal grid structure; each unit integrates a PIN diode array and a bias circuit; when the driving circuit layer applies a bias voltage through the bias circuit, the diode conduction state changes the equivalent electrical length of the SRR, achieving continuous adjustment of the unit resonant frequency in the range of 4.5-15GHz, and a reflection phase control range of ≥320°.

[0021] In conjunction with the first aspect, in some implementations of the first aspect, the execution unit satisfies at least one of the following:

[0022] The SRR unit has an outer diameter of 4.8±0.1mm, a line width of 0.3±0.02mm, and an opening spacing of 0.2mm. It is supported by an aluminum nitride substrate with a dielectric constant of 9.8 and a loss tangent of 0.002. The metal grid period is 6mm and the line width is 0.5mm. It is prepared on the surface of alumina ceramic by photolithography.

[0023] The execution unit layer uses silicon carbide packaging technology to ensure that the structural deformation is ≤5μm at a high temperature of 250°C, ensuring the stability of stealth performance over a wide temperature range.

[0024] Compared with the prior art, the solution provided by the present invention includes at least the following beneficial technical effects:

[0025] (1) The designed high-temperature resistant intelligent stealth structure reduces the average signal-to-noise ratio of the incident signal by 13 dB in the 6-12.5 GHz frequency band, providing support for the material's broadband stealth capability.

[0026] (2) The designed high-temperature resistant intelligent stealth structure can withstand temperatures up to 250°C, providing support for the high-temperature resistant properties of intelligent stealth materials.

[0027] (3) The designed high-temperature resistant intelligent stealth structure adjusts the phase coverage from -180° to 180°, ensuring the angle range during actual use.

[0028] (4) The electromagnetic response time of the designed high-temperature resistant intelligent stealth structure adaptive radar stealth system is less than 10ms, which meets the large-angle rapid response requirements in actual use scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the structure of high-temperature resistant intelligent stealth material.

[0030] Figure 2 Schematic diagram of the absorbing metamaterial sample and test scenario.

[0031] Figure 3 Schematic diagram of the temperature-dependent reflectivity test system. (a) Test principle diagram, (b) Bow method test scene diagram. DETAILED DESCRIPTION

[0032] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0033] The present invention provides a high temperature resistant intelligent stealth material structure, such as Figure 1 The stealth material structure comprises a high-temperature resistant, uniformly wave-transmitting material and a vertically integrated intelligent stealth structure layer, which includes an electromagnetic environment sensing module, an execution unit layer, a drive circuit layer, and a control circuit layer. The intelligent stealth structure layer utilizes a multi-layer collaborative architecture to achieve dynamic perception, decision-making, and execution control of the electromagnetic environment.

[0034] A high-temperature resistant, uniformly wave-transmitting material uses a two-dimensional, orthogonal woven quartz fiber fabric as reinforcement, with a high-purity quartz ceramic or nitride ceramic matrix. The layered composite material is prepared through an impregnation-hot pressing and sintering composite process. In some embodiments, the reinforcement is a two-dimensional, orthogonal quartz fiber fabric with a warp density of 16±0.5 bundles / cm and a weft density of 12±0.5 bundles / cm. The fiber has a single filament diameter of 9±0.5 μm and is surface-treated with a silane coupling agent to form a chemically bonded interface with the matrix. In some embodiments, the matrix is ​​a high-purity quartz ceramic with a SiO2 content of ≥99.9wt% or a nitride ceramic with a Si3N4 content of ≥95wt%. The matrix layer thickness is controlled within the range of 0.2-0.5mm.

[0035] In some embodiments provided herein, the high-temperature resistant, uniformly wave-transparent material utilizes a three-step impregnation-lamination-hot-pressing sintering process. First, the pretreated quartz fiber fabric is vacuum-impregnated in a matrix slurry for 30 minutes, with the slurry solids content controlled at 45-50 vol%. Layers are then stacked with a preload of 0.5 MPa, and after every five layers, a 2 MPa pressure is applied and maintained for 10 minutes. Finally, a gradient sintering process is performed under argon protection, heating at a rate of 5°C / min to 1350°C (quartz-based) or 1650°C (nitride-based), maintaining the temperature for 2 hours, and then cooling in the furnace.

[0036] This preparation method enables the material to exhibit excellent performance in the 2-18 GHz frequency band with a dielectric constant of 2.82-2.92 and a loss tangent of ≤0.003. In the 2-18 GHz band, the theoretical power transmission coefficient is greater than 86%, the thermal conductivity is around 800 W / K, and the thermal expansion coefficient is 10-6K. -1The fundamental reasons for this are: ① The low dielectric loss characteristics of quartz fiber (tanδ≤0.001) work synergistically with the broadband impedance matching characteristics of the matrix material (that is, the dielectric properties of quartz fiber are superior to those of ordinary glass fiber, with the loss tangent tanδ and dielectric constant ε being the lowest in the glass fiber system and remaining essentially unchanged over a wide frequency band. Furthermore, quartz fiber has excellent compatibility with resin matrices such as phenolic resin and epoxy resin, making it more suitable as a reinforcement material for high-frequency wave-transmitting antenna covers); ② The dense interface layer (50-100nm thick) formed by the hot pressing process effectively suppresses interfacial polarization loss; ③ The multi-layer orthogonal braided structure achieves broadband wave transmission through the multiple reflection mechanism of electromagnetic waves, with a measured power transmission coefficient of >86%; ④ The thermal expansion coefficient of the matrix material (α=3.2×10-6 / K) matches that of the reinforcement, resulting in a performance degradation of <5% after 10 thermal shock cycles at 800°C.

[0037] Within the intelligent stealth structure, the electromagnetic environment sensing module utilizes a composite sensor network consisting of a microstrip antenna array and an open-loop antenna, distributed in a 0.5cm grid pattern across the surface of the high-temperature-resistant, wave-transparent substrate. The microstrip antenna captures the electric field component in the 6-12.5GHz frequency band, while the open-loop antenna detects the magnetic field component. This signal is then processed by a low-noise amplifier (gain >40dB) and a bandpass filter to generate a dual-polarized digital signal.

[0038] The control circuit layer is the decision-making center of the intelligent stealth structure layer, responsible for processing the data collected by the sensing module and making decisions according to the preset algorithm. The circuit in the present invention uses a high-performance digital signal processor (DSP) and a field programmable gate array (FPGA) as the main processing units. The DSP is responsible for performing complex data processing and algorithmic operations, while the FPGA is used to achieve fast logic control and signal processing. The DSP runs an electromagnetic feature extraction algorithm based on a deep neural network (model depth 8 layers, parameter quantity 2.3M), and the FPGA achieves millisecond-level reconstruction of the coding sequence (operation cycle <5ms). The two exchange data through the PCIe 3.0 bus.

[0039] The control circuit layer also includes a high-speed data bus and wireless communication module for high-speed data transmission and remote control between modules. Specifically, the wireless communication module connects to the electromagnetic environment sensing module via a 24-channel ADC (sampling rate 1GS / s). After using a Butterworth bandpass filter (passband 6-12.5GHz) to eliminate out-of-band noise, the data is transmitted via a PCle3.0×8 bus to a DSP (model TMS320C6678) to execute the environmental feature extraction algorithm based on a deep residual network (network depth 12 layers, parameter count 5.6M). Simultaneously, an FPGA (model Xilinx Kintex-7) processes 256 control instructions in parallel. The two achieve 4.8GB / s data exchange through shared memory.

[0040] In addition, the control circuit layer also integrates a power management module to provide a stable power supply for the entire system and rationally allocate energy according to the power requirements of each module. Specifically, the power management module of the control circuit layer is equipped with a three-stage voltage regulation circuit (input 28V / output 1.2-12V adjustable), uses silicon carbide power devices to achieve 94% conversion efficiency, and integrates triple protection mechanisms for overvoltage, undervoltage, and short circuit.

[0041] In addition, the control circuit layer also includes a heat dissipation module. The heat dissipation module uses a graphene-aluminum nitride composite substrate (thermal conductivity 620W / m·K) combined with a micro-channel liquid cooling structure to ensure that the chip junction temperature is ≤85°C in high-temperature environments.

[0042] The control circuit layer provided by the present invention achieves a real-time response of 8.3ms within an operating range of -40°C to 125°C (a 62% improvement over traditional solutions). Its advantages are: ① The heterogeneous architecture fully utilizes the advantages of DSP algorithm processing and FPGA parallel computing to compress the electromagnetic feature recognition time to 1.2ms; ② Multi-level power management controls voltage fluctuations within ±0.5%, ensuring the stability of precision control signals; ③ The composite heat dissipation design enables a power density of 15W / cm 2 The temperature rise does not exceed 12℃, ensuring long-term reliable operation in harsh environments.

[0043] The driving circuit layer is the executive nerve of the intelligent stealth structure layer, responsible for converting the decision of the control circuit layer into the action of the execution unit layer. The driving circuit layer of the present invention adopts a three-stage current amplification architecture (total amplification factor 10 4 ) and high temperature stable transmission design.

[0044] The three-stage current amplification architecture comprises a preamplifier module, an intermediate amplifier module, and a final driver module. This architecture achieves millisecond-level high-precision control through the collaborative design of gallium nitride (GaN) power devices and a copper pillar array. Specifically, GaN power devices convert the 0-3.3V control signal into a 0-100V bias voltage, which is then transmitted to the execution unit layer via the copper pillar array. The preamplifier module uses a low-noise operational amplifier (40dB gain) for primary amplification of the 0-3.3V PWM signal output from the control circuit layer. Its input stage features a differential circuit with a common-mode rejection ratio (CMRR) >120dB to mitigate electromagnetic interference. The intermediate amplifier module utilizes GaN HEMT devices to construct a push-pull power amplifier circuit (operating bandwidth DC-20MHz), which boosts the voltage to 0-50V via a negative feedback compensation network. The final driver module utilizes an LDMOS power transistor array to achieve a 100V high-voltage output. Each driver unit is equipped with an independent overcurrent protection circuit (response time <1μs).

[0045] The high-temperature stable transmission design of the driving circuit layer is three-dimensionally integrated through a multi-layer ceramic substrate (aluminum oxide content ≥ 96%), and a gold wire bonding process is used to connect various functional modules. A copper pillar array with a spacing of 0.5mm is configured at the output end to realize parallel signal transmission of the 256×256 execution unit layer.

[0046] After testing, the driver circuit layer can still maintain 98% power conversion efficiency in a high temperature environment of 250℃, with an output bias voltage accuracy of ±0.5V and a signal transmission delay of <50ns. Its technical advantages are as follows: ① The three-stage amplification architecture ensures a total amplification factor of 10^4 while utilizing the high electron mobility characteristics of GaN devices (>2000cm 2 / V·s) achieves broadband, low-distortion amplification; ② The difference in thermal expansion coefficients between the ceramic substrate and the copper pillar array is less than 0.5×10^-6 / K, reducing high-temperature thermal deformation to less than 2μm, ensuring long-term reliability of the circuit connection; ③ A distributed temperature sensor network monitors the temperature rise of each node in real time, and a dynamic power allocation algorithm controls local temperature differences within ±5°C. This design effectively addresses the challenges of efficiency degradation, signal distortion, and thermal runaway in traditional drive circuit layers at high temperatures, providing critical support for millisecond-level real-time control of the intelligent stealth structure layer.

[0047] The execution unit layer is the physical execution part of the intelligent stealth structure layer, which directly interacts with external electromagnetic waves to achieve stealth or change the target radar cross section (RCS). The execution unit layer provided by the present invention includes a periodically arranged two-dimensional metamaterial array.

[0048] The unit structure of the execution unit layer includes an anisotropic composite resonator design, including a vertically stacked double split-ring resonator (Split-ring resonator, SRR) and a metal grid structure. In one embodiment, the SRR unit has an outer diameter of 4.8±0.1mm, a line width of 0.3±0.02mm, an opening spacing of 0.2mm, and is supported by an aluminum nitride substrate (ε=9.8, tanδ=0.002); the metal grid period is 6mm, the line width is 0.5mm, and it is prepared on the surface of alumina ceramic (purity ≥99.6%) by photolithography. This combination of geometric parameters can enable the unit to produce dual resonance characteristics in the 6-18GHz frequency band. By adjusting the SRR opening direction and the grid polarization direction to form electromagnetic coupling, full polarization wave phase modulation is achieved.

[0049] The two-dimensional metamaterial array at the actuator layer adopts a 256×256 matrix layout, with each unit integrating a PIN diode array (model SMP1320-079LF) and bias circuitry. When a 0-100V bias voltage is applied to the driver circuit layer, the diode conduction state changes the equivalent electrical length of the SRR, enabling continuous adjustment of the unit's resonant frequency between 4.5 and 15 GHz, with a reflection phase control range of ≥320°. The bias circuitry features serpentine bias lines (50μm width, 80μm spacing) to enable independent unit control while ensuring high-frequency signal integrity.

[0050] To achieve high and uniform digital state reflection, the actuator layer utilizes a square patch structure, achieved by printing metal squares of varying sizes atop a dielectric substrate (F4B, with a dielectric constant of 2.65 and a loss factor of 0.001). Due to the metal coating on the backside of the substrate, this structure typically exhibits a reflection amplitude exceeding 0.85. By adjusting the side length of the patch, a reflection phase range of 270° can be covered at the target frequency, sufficient for constructing one- and two-dimensional coded metasurfaces. A major advantage of coded metasurfaces is the ability to manipulate electromagnetic waves by varying the coding sequence. These coding sequences determine how the coded particles with different digital states are arranged in a two-dimensional plane. For example, using three different coding patterns—"000000...", "010101...", and a checkerboard pattern—results in single-beam, dual-beam, and quad-beam scattering patterns, respectively, when illuminated by a plane wave. Then, through deep learning methods, a direct mapping relationship between "reflection spectrum" and "unit bias voltage" is established, and a millisecond-level neural network module is constructed to achieve real-time regulation of its own electromagnetic characteristics, and the electromagnetic response time of the adaptive radar stealth system is less than 10ms.

[0051] In some embodiments, the execution unit layer uses a silicon carbide packaging process (CTE = 3.1×10^-6 / °C) to ensure that the structural deformation is ≤5μm at a high temperature of 250°C, thereby ensuring the stability of stealth performance over a wide temperature range.

[0052] The execution unit layer consists of 256×256 metamaterial units, each containing a tunable split-ring resonator (linewidth accuracy ±2μm) and a PIN diode array. The unit's resonant frequency (adjustable range: 4.5-15GHz) is controlled by bias voltage, enabling 360° continuous control of the reflected phase. The stealth execution steps of the intelligent stealth structure layer include: a) The electromagnetic induction module captures the incident wave frequency / polarization parameters in real time and generates an optimal coding sequence through a DSP neural network; b) The FPGA converts the coding sequence into a unit bias voltage matrix, which is then driven by a three-stage GaN amplifier and loaded into the execution unit layer; c) Each unit in the execution unit layer changes its resonant state according to the voltage command, reconstructing the surface impedance distribution within 8ms to attenuate the peak radar cross section (RCS) by ≥13dB.

[0053] In summary, the intelligent stealth structure layer still maintains a stealth performance of more than 13dB in a high-temperature environment of 250°C. Its technical advantages are due to: ① The dual-polarization sensor network realizes full-dimensional capture of electromagnetic parameters, making the environmental perception error less than 0.5dB; ② The heterogeneous processing architecture compresses the algorithm response time to 8.3ms, which is 62% higher than the traditional solution; ③ The GaN drive circuit layer maintains 98% power conversion efficiency at high temperatures, ensuring the control accuracy of the execution unit layer; ④ The metamaterial unit adopts silicon carbide packaging technology, and its thermal expansion coefficient (3.1×10^-6 / K) perfectly matches the substrate, making the high-temperature deformation less than 5μm, ensuring structural stability and stealth performance consistency.

[0054] The high temperature resistant intelligent stealth material structure and test scenario provided by the present invention are as follows Figure 2 and Figure 3 shown.

[0055] (1) Sample microwave absorption performance test

[0056] In order to further test the incident angle and polarization stability of the sample, an arch measurement system test platform was used to evaluate the stealth performance of the material in different frequency ranges, such as Figure 2 As shown. One of the horn antennas fixed on the arch is set as a transmitting antenna, and the other horn antenna is set as a receiving antenna. Both are connected to a vector network analyzer. The operating frequency of the two horn antennas is 1-18 GHz. By rotating the robotic arm, the incident angle of the electromagnetic wave can be modulated to obtain TE and TM polarized waves. Under normal incidence, by rotating the angle between the sample and the antenna, the absorption rate test results of four rotation azimuth angles (phi) of 0°, 45°, 90°, and 135° are obtained. Through structural optimization, its stealth performance in the 6-12.5 GHz frequency band is ensured to be greater than 13dB.

[0057] (2) Real-time temperature resistance and stealth performance test

[0058] For the designed intelligent stealth system, real-time stealth performance and temperature resistance tests are carried out, and the temperature-sensitive response ability of the material is tested in a rapid heating and cooling environment to ensure that it can adaptively adjust the electromagnetic characteristics according to temperature changes within 10ms and meet the environmental tolerance temperature of 250°C. In order to characterize the absorbing performance of the absorbing metamaterial in high-temperature environments from room temperature to high temperature, a reflectivity temperature-varying test system based on the bow method is used. The schematic diagram of the test system is shown below. Figure 3 As shown, the test environment is in a microwave darkroom to reduce the error caused by clutter in the test environment.

[0059] The test used a horn antenna connected to a vector network analyzer to transmit and receive electromagnetic waves. Its operating frequency range was 1-18 GHz. The horn antenna was mounted on two robotic arms whose angle of incidence was computer-controlled. The prepared absorbing metamaterial was affixed to an aluminum plate in the heating device. This not only heated the sample under test but also served as a metal backing for the metamaterial, eliminating transmission. In practice, since the heating plate dissipates heat into the surrounding space, a porous alumina ceramic was placed on the surface of the test sample for insulation. The plate was heated to 280°C and held at this temperature for 15 minutes, aiming for a temperature of 250°C. The porous insulating ceramic was then removed during testing. However, due to the large size of the heating surface and the uneven heating method, the temperature distribution on the heating plate was also uneven. The temperature at the center of the heating plate was approximately 280°C, while the surrounding temperatures ranged from approximately 200°C to 250°C.

[0060] The steps of the bow method test mainly include: confirming that the system connection is normal; turning on the power; starting the vector network analyzer; setting the test parameters - frequency range, S parameters, number of scan points and intermediate frequency bandwidth; calibrating the system and saving the S parameters of the standard metal plate; clamping the sample, heating, testing the sample S parameters and calculating the absorption rate; saving the data, shutting down the system and cleaning up the site.

[0061] Although the present invention is disclosed above in terms of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined by the claims of the present invention.

Claims

1. A high temperature resistant intelligent stealth material structure, characterized in that: It includes high-temperature resistant uniform wave-transparent materials, and also includes an intelligent stealth structure layer constructed in a vertically integrated manner. The intelligent stealth structure layer includes an electromagnetic environment sensing module, an execution unit layer, a drive circuit layer and a control circuit layer; the intelligent stealth structure layer adopts a multi-layer collaborative architecture to realize dynamic perception-decision-making-execution control of the electromagnetic environment, wherein the electromagnetic induction module captures the incident wave frequency-polarization parameters in real time, generates the optimal coding sequence through the control circuit layer and converts it into a unit bias voltage matrix, which is driven by the drive circuit layer and loaded to the execution unit layer; each unit in the execution unit layer changes the resonance state according to the voltage instruction.

2. The high temperature resistant intelligent stealth material structure according to claim 1, characterized in that: The high-temperature resistant uniform wave-transmitting material adopts two-dimensional orthogonal woven quartz fiber fabric as reinforcement and high-purity quartz ceramic or nitride ceramic as matrix, and the layered structure composite material is prepared by impregnation-hot pressing sintering composite process.

3. The high temperature resistant intelligent stealth material structure according to claim 2, characterized in that: The high temperature resistant uniform wave-transmitting material meets at least one of the following requirements: The reinforcement is a two-dimensional orthogonal quartz fiber fabric with a warp density of 16±0.5 bundles / cm and a weft density of 12±0.5 bundles / cm. The fiber monofilament diameter is 9±0.5μm and is surface treated with a silane coupling agent to form a chemical bonding interface with the matrix. The substrate is made of high-purity quartz ceramics with SiO2 content ≥99.9wt% or nitride ceramics with Si3N4 content ≥95wt%, and the thickness of the substrate layer is controlled in the range of 0.2-0.5mm; The high-temperature resistant, uniform, and wave-transparent material adopts a three-step impregnation-lamination-hot-pressing sintering process: first, the pretreated quartz fiber fabric is vacuum-impregnated in the matrix slurry for 30 minutes, and the solid content of the slurry is controlled at 45-50 vol%. Then, the layers are stacked with a pre-pressure of 0.5 MPa. After every 5 layers, a pressure of 2 MPa is applied and maintained for 10 minutes. Finally, gradient sintering is carried out under argon protection, and the temperature is raised to 1350°C (quartz-based) or 1650°C (nitride-based) at a rate of 5°C / min. After holding for 2 hours, the material is cooled in the furnace.

4. The high temperature resistant intelligent stealth material structure according to claim 1, characterized in that: The electromagnetic environment sensing module uses a composite sensor network consisting of a microstrip antenna array and an open-loop antenna, which is distributed in a grid pattern with a spacing of 0.5 cm on the surface of a high-temperature resistant and wave-transparent substrate. The microstrip antenna captures the electric field component in the 6-12.5 GHz frequency band, and the open-loop antenna detects the magnetic field component. After processing by a low-noise amplifier (gain > 40 dB) and a bandpass filter, a dual-polarized digital signal is formed.

5. The high temperature resistant intelligent stealth material structure according to claim 1, characterized in that: The control circuit layer includes a high-performance digital signal processor DSP, a field-programmable gate array FPGA, a data bus and a wireless communication module; the wireless communication module is connected to the electromagnetic environment sensing module, and after using a bandpass filter to eliminate out-of-band noise, it is transmitted to the DSP via the data bus to execute the environmental feature extraction algorithm based on the deep residual network. At the same time, the FPGA parallel processes the control instructions generated by the execution unit layer.

6. The high temperature resistant intelligent stealth material structure according to claim 5, characterized in that: The control circuit layer also includes at least one of the following: Power management module, the power management module is equipped with a three-stage voltage stabilization circuit, uses silicon carbide power devices to achieve 94% conversion efficiency, and integrates a triple protection mechanism of overvoltage / undervoltage / short circuit; The heat dissipation module adopts a graphene-aluminum nitride composite substrate and combines it with a microchannel liquid cooling structure to ensure that the chip junction temperature is ≤85°C in a high temperature environment.

7. The high temperature resistant intelligent stealth material structure according to claim 1, characterized in that: The drive circuit layer adopts a three-stage current amplification architecture, which includes a pre-amplifier module, an intermediate amplifier module and a final drive module; the pre-amplifier module uses a low-noise operational amplifier to perform primary amplification of the signal output by the control circuit layer, and its input stage is configured with a differential circuit with a common-mode rejection ratio of >120dB to eliminate electromagnetic interference; the intermediate amplifier module uses GaN HEMT devices to construct a push-pull power amplifier circuit, and increases the voltage to 0-50V through a negative feedback compensation network; the final drive module uses an LDMOS power tube array to achieve 100V high-voltage output, and each drive unit is equipped with an independent overcurrent protection circuit.

8. The high temperature resistant intelligent stealth material structure according to claim 1, characterized in that: The driving circuit layer uses a multi-layer ceramic substrate with an aluminum oxide content of ≥96% for three-dimensional integration, uses a gold wire bonding process to connect various functional modules, and configures a copper pillar array at the output end to realize parallel transmission of signals at the execution unit layer.

9. The high temperature resistant intelligent stealth material structure according to claim 1, characterized in that: The execution unit layer includes a periodically arranged two-dimensional metamaterial array, wherein multiple coding patterns of the two-dimensional metamaterial array are used to generate multiple beam scattering patterns under plane wave illumination; The unit structure of the execution unit layer includes a vertically stacked double split-ring resonator (SRR) and a metal grid structure; each unit integrates a PIN diode array and a bias circuit; when the driving circuit layer applies a bias voltage through the bias circuit, the diode conduction state changes the equivalent electrical length of the SRR, achieving continuous adjustment of the unit resonant frequency in the range of 4.5-15GHz, and a reflection phase control range of ≥320°.

10. The high temperature resistant intelligent stealth material structure according to claim 9, characterized in that: The execution unit meets at least one of the following conditions: The SRR unit has an outer diameter of 4.8±0.1mm, a line width of 0.3±0.02mm, and an opening spacing of 0.2mm. It is supported by an aluminum nitride substrate with a dielectric constant of 9.8 and a loss tangent of 0.

002. The metal grid period is 6mm and the line width is 0.5mm. It is prepared on the surface of alumina ceramic by photolithography. The execution unit layer uses silicon carbide packaging technology to ensure that the structural deformation is ≤5μm at a high temperature of 250°C, ensuring the stability of stealth performance over a wide temperature range.

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