44 results about "Stealth technology" patented technology

The invention relates to a camouflage design method and system based on an adversarial sample, and aims to solve the problem that a current camouflage pattern is difficult to adapt to a multi-terrain background camouflage demand, and the method comprises the steps: constructing a training data set; carrying out adversarial camouflage texture initialization by adopting a multi-scale adaptive disturbance weighted Voronoi graph; constructing a camouflage texture generation model based on the confrontation camouflage texture initial value; generating a camouflage target image in the physical scene based on the target mask image in combination with the original image and the camouflage texture output by the camouflage texture generation model, calculating an adversarial loss function through the adversarial image, and obtaining the camouflage color with the optimal effect by iteratively training the camouflage texture generation model; the method can effectively interfere with the recognition capability of the AI detection model, is suitable for the stealth technology, privacy protection, security and other scenes, and remarkably improves the efficiency and adaptability of the camouflage technology.

This invention discloses a wide-bandwidth, wide-angle metamaterial microwave absorber covering the L, S, C, X, and Ku bands, belonging to the field of stealth technology. The unit structure of the microwave absorber includes an upper FR4 plate with three-dimensional printed high-resistivity carbon paste, a middle paper honeycomb support layer, and a bottom magnetic material attached to a metal plate. The upper FR4 plate provides microwave absorption performance at mid and high frequencies, while the bottom magnetic material provides microwave absorption performance at low frequencies. The two are fixed by the paper honeycomb of the middle support layer. By combining a three-dimensional microwave absorber with magnetic materials, this invention achieves wide-bandwidth, wide-angle microwave absorption performance. The composite microwave absorber structure constructed by this invention has high structural strength and achieves lightweight design.

The application discloses 3D printing aramid wave-absorbing honeycomb material and a preparation method and application thereof, utilizes wave-absorbing agents with nano-scale structure and excellent electrical properties and aramid nanofibers with excellent mechanical properties to be tightly combined through hydrogen bonds, and advantages that the surface of the wave-absorbing agents and the aramid nanofibers is easy to produce a strong network cross-linking structure, and the mechanical properties of the 3D printing aramid wave-absorbing honeycomb material are improved, a new aramid nanofiber-based material with good wave-absorbing performance and mechanical properties is developed, and the defects of the current wave-absorbing honeycomb material, such as a large weight of a surface coating and easy peeling, are solved, and the application demand in the fields of aerospace, radar stealth technology and the like can be met. The 3D printing technology is used to print aramid wave-absorbing honeycomb materials with different sizes and densities, energy consumption is low, printing precision is high, the process is simple, the 3D printing aramid wave-absorbing honeycomb material has excellent mechanical properties, good wave-absorbing performance, strong structure designability, and a wide application prospect.

This invention discloses a method for preparing and controlling the emissivity of infrared stealth MXene thin films, belonging to the field of infrared stealth technology. The method uses Ti3C2T... X Using MXene as a raw material, it is coated onto a graphite plate as the anode and a platinum mesh as the cathode. Electrolysis is performed for 5 minutes in a tannic acid-sodium chloride aqueous electrolyte at 5V. After ultrasonication, centrifugation, and washing, e-MXene is obtained. The e-MXene film is then obtained by filtration, or it can be composited with BC nanocellulose to obtain an e-BC-MXene film. This invention achieves efficient MXene modification through anodic electrochemical exfoliation. The synergistic effect of tannic acid and sodium chloride enhances its antioxidant properties and structural integrity. The resulting film can be water-controlled by humidity and electrothermally controlled by current. Compared with the traditional cathode exfoliation method, the yield, sheet size, and control responsiveness are significantly improved. The preparation process is green and low-consumption. The film is suitable for adaptive infrared stealth requirements in complex scenarios and has broad application prospects.

According to the opposition binary power multistage superconductive anti-gravity cold and hot gas separation stealth technology, the air cold and hot gas separation technology is applied, a graphene superconductive material structure is used as a multistage superconductive cold and hot gas separation technology guide sheet, and the multistage superconductive anti-gravity air cold and hot gas separation technology and the multistage superconductive anti-gravity stealth stealth technology are formed; an electromagnetic field in the air can be separated into a microwave field, so that the silencing and hiding effects are achieved; the invention discloses an opposite binary power multistage superconductive antigravity gas separation stealth silencing technology which is a basic technology of a multistage superconductive antigravity technology, a multistage superconductive silencing technology and a multistage superconductive stealth technology structure foundation. 1, a stealth technology mounting plate for opposition binary power multi-stage superconductive anti-gravity cold and hot gas separation noise elimination; 2, a vertical binary power multistage superconductive anti-gravity cold and hot gas separation silencing invisible structure guide sheet;

The present invention discloses a broadband paper-based honeycomb microwave absorber with bidirectional impedance gradient, relating to the field of electromagnetic radar stealth technology. The absorber comprises a paper-based honeycomb structure comprising N periodically arranged paper-based honeycomb units, each of which has a grounded metal base. Each honeycomb unit comprises six honeycomb walls, which are sequentially designated as first to sixth honeycomb walls. The first to sixth honeycomb walls each have an inner surface printed with an impedance gradient structure; alternatively, the second, fourth, and sixth honeycomb walls each have an inner surface printed with an impedance gradient structure; alternatively, the second, third, fifth, and sixth honeycomb walls each have an inner surface printed with an impedance gradient structure. The impedance gradient structure is constructed using carbon paste and silver paste, achieving a bidirectional impedance gradient from free space to the grounded metal base. The present invention provides a paper-based honeycomb microwave absorber with a lightweight load-bearing capacity, a broadband, low profile, and a small thickness.

An embodiment of the present invention discloses a system for adjusting a frequency-selective absorber, relating to the field of stealth technology. This system enables the frequency-selective absorber to switch its operating mode, thereby achieving tunable performance in its frequency band, and has broader application prospects. The present invention includes: a host computer connected to both a temperature sensor and a water pump device, the water pump device being mounted on the frequency-selective absorber; the water pump device being connected to the water channel and liquid storage tank of the frequency-selective absorber. The temperature sensor is used to collect temperature information and transmit it to the host computer; the host computer is used to determine whether to perform liquid exchange based on the temperature information, and if so, trigger the water pump device to operate, thereby extracting or refilling the liquid in the frequency-selective absorber.

The application discloses a kind of space target luminosity dynamic measurement ground test system, the system includes: multiple degrees of freedom controllable rotary table, controllable rotary table is connected with satellite scale model, and controllable rotary table is used to drive satellite scale model multi-angle rotation adjustment;Visible light detection unit is located in the direction of satellite scale model reflected light path, it is used to image satellite scale model and generates continuous observation image sequence;Light source unit, it is used to simulate the parallel light source of sun, and light source is directly on satellite scale model;And general control unit.General control unit is used to control light source intensity, rotary table motion parameter and image acquisition, and image data is reduced sampling processing, generates the luminosity sequence of simulated long-distance observation.The technical scheme provided by the application can provide reliable technical support for space target identification, orbit prediction and stealth technology verification, with innovation, practicality and economy.

The application relates to a variable sweep wing stealth aircraft afterbody wedge shape design method, and belongs to the field of aircraft general design and stealth technology. The application is simple and practical in shape; comprehensive design factors are considered, and comprehensive requirements such as variable tail wing rotation, component coupling, stealth principle and aerodynamic resistance are covered; design constraints can be accurately converted into geometric design; variable tail wing rotation, the stealth principle, aerodynamic resistance and component coupling can be effectively converted into afterbody wedge shape point position and line tangent vector control design to be realized; the fusion design of the afterbody wedge and the surrounding curved surface is better realized; under the premise of guaranteeing the variable tail wing rotation space requirement and the binary nozzle requirement, the aerodynamic and stealth shape integration design of the afterbody wedge shape is realized. The application is mainly applied to the scheme design of the afterbody wedge shape of the variable tail wing. The method is novel, ingenious and compact in structure, has strong applicability, has a wide application range, and has a wide application prospect in the design of military aircraft.

The invention discloses a broadband electromagnetic dipole antenna based on an X-shaped polarization conversion metasurface, and belongs to the technical field of electromagnetic dipole antennas. In order to solve the problems that an existing metamaterial wave absorber RCS is narrow in reduction bandwidth, an RCS antenna of a PCM chessboard structure is concentrated at the frequency band below 20 GHz and the like, the electromagnetic dipole antenna combines a 1 * 8 electromagnetic dipole array with the PCM chessboard structure, and the RCS is minimized while high gain and wide frequency band are kept; by using the X-shaped PCM unit and the mirror image unit array thereof, cross polarization conversion of reflected waves is realized in a working frequency band, a 180-degree phase difference is generated, the PCM disperses back scattering energy to a surrounding area, and normal reflection is reduced, so that the RCS of the antenna is effectively reduced, and the RCS is reduced by more than 10 dB in 74.1% of bandwidth (19.07-41.52 GHz). The electromagnetic dipole antenna disclosed by the invention has the characteristics of high gain, wide bandwidth and low RCS (radar cross section), has a wide application prospect in the fields of high-frequency wireless communication and radar stealth, and shows huge potential of future development of a stealth technology.

The invention relates to the technical fields of electromagnetic sensing, stealth technology and electromagnetic wave regulation and control. An existing sensor structure still has the limitations that invisibility, signal enhancement and stable electric connection cannot be achieved at the same time, and the sensitivity and the invisibility performance restrict each other. The invention discloses an electromagnetic sensor stealth structure capable of enhancing sensitivity, which is characterized in that a plurality of hidden areas and a high-refractive-index core detection area are arranged in an anisotropic medium shell layer, and sub-wavelength communication holes are formed between the hidden areas and the high-refractive-index core detection area; electromagnetic waves can be guided to bypass the sensor main body to realize invisibility, meanwhile, the electromagnetic waves are converged to a high-refractive-index core detection area to realize signal enhancement, and the effect of stable electric connection between the sensor main body and the probe is maintained; the method is applied to the fields of ultra-weak signal detection, stealth monitoring, biosensing, radar detection and the like.

This invention discloses a stealthy metasurface compatible with radar, infrared, and acoustic fields, relating to the field of electromagnetic stealth technology. The invention involves placing a resonant metal square ring on the top surface of a dielectric substrate, with metal patches of varying sizes placed on both the inner and outer regions of the resonant metal square ring on the top surface of the dielectric substrate, and a metal backplate on the bottom surface of the resonant metal square ring. Quarter-circle arcs are formed at the four corners of the dielectric substrate and the metal backplate. Multiple dielectric substrates are rotated in different directions to alternately arrange them into a metasurface. A cavity structure is then formed on the bottom surface of the metasurface, with multiple cylindrical cavities formed at the intersections of the dielectric substrates communicating with the cavity structure to form a micro-perforated plate structure. When electromagnetic waves and acoustic waves are incident on the metasurface, radar stealth, infrared stealth, and sound absorption and noise reduction functions can be achieved simultaneously. The invention also achieves a coupling design of electromagnetic and acoustic fields to simultaneously modulate electromagnetic and acoustic fields.

The application discloses a preparation method and application of a multilayer carbon sphere material. Hollow carbon spheres are obtained by a hard template method, silica is used as a core, and phenolic resin (RF) is used as a shell. The multilayer hollow carbon spheres can be obtained by repeatedly and alternately wrapping the silica and the phenolic resin and then carbonizing and removing the core. By adjusting the particle size of the silica, multilayer carbon spheres with different particle sizes can be obtained. By adjusting the number of layers covered by the phenolic resin, the number of layers of the multilayer hollow carbon spheres can be adjusted. The hollow structure of the hollow carbon spheres reflects and scatters electromagnetic waves, and the interface polarization between the multilayer shells makes the multilayer hollow carbon spheres have excellent absorption effect on electromagnetic waves. The application provides a new preparation method for the multilayer hollow carbon spheres, successfully prepares single-layer, double-layer and three-layer carbon spheres with different particle sizes, the synthesis method is simple, raw material prices are low, and the obtained material has a wide application prospect in stealth technology.

The application discloses a Jerusalem unit double-layer FSS broadband wave-absorbing structure and a preparation method and application thereof, and belongs to the field of electromagnetic wave-absorbing technology design in electromagnetic stealth technology. The structure is sequentially arranged from bottom to top as a metal bottom layer, a dielectric layer 1, a patterned resistance layer 1, a dielectric layer 2 and a patterned resistance layer 2. Periodic array distributed multiple unit cell structures are formed on the surfaces of the patterned resistance layer 1 and the patterned resistance layer 2, and each unit cell structure adopts a Jerusalem cross pattern. The Jerusalem unit double-layer FSS broadband wave-absorbing structure provided by the application has a wide-frequency absorption characteristic. Through the regulation of geometric sizes on a macro scale and the structure design on a micro scale, the wave-absorbing structure can realize an absorption rate of more than 99% in a full frequency band of 8-12 GHz, and has a good absorption effect on low-frequency electromagnetic waves.

The invention relates to the field of titanium alloy grinding, in particular to a titanium alloy anti-radar stealth technology superfinishing grinding method which comprises the following steps that a titanium alloy workpiece is placed on a feeding mechanism, the titanium alloy workpiece is conveyed to a grinding base installed on a workbench along with the feeding mechanism, and then a clamping mechanism is started to fix the titanium alloy workpiece; dry rough grinding is carried out, a precise pneumatic grinding instrument is used for attaching a rough grinding sheet, a machine switch is turned on, and rough grinding is carried out till no machining knife lines exist on the surface; semi-fine grinding: attaching a fine grinding sheet by using a precision pneumatic vibration instrument, turning on a machine switch, and performing fine grinding until the observation surface of the magnifying lens has no coarse grains; coarse wet grinding is conducted, specifically, a precise pneumatic vibration instrument is used for being attached with a fine grinding sheet, and special wet grinding liquid is prepared till the wet grinding surface is slightly darkened; fine polishing is conducted, a precise pneumatic polishing instrument is used for being attached with a plant fiber grinding sheet, special polishing paraffin is configured, and the polished surface gradually becomes bright from dark. The problem that the grinding quality of the surface of the titanium alloy workpiece is poor is solved.

The application relates to the technical field of wave-absorbing materials, and particularly discloses a Zn-Fe-Mn oxide-hard carbon composite material, a preparation method and application thereof. A pomegranate-shaped sphere is prepared through a co-precipitation-calcination method; then, the pomegranate-shaped sphere is uniformly dispersed in a self-prepared solvent combination, and the mixture is solidified and formed through heating treatment; finally, annealing treatment is carried out on the Zn-Fe-Mn oxide-hard carbon composite material in an 800 DEG C high-temperature tube furnace under an argon protection atmosphere (flow rate: 100 sccm). The composite material has a unique three-dimensional layered structure, exhibits excellent wide-band microwave absorption characteristics, and can realize efficient electromagnetic wave attenuation. The application opens up a new way for the structural design and optimization of high-performance wave-absorbing materials, and has a wide application prospect in the fields of advanced stealth technology and novel electromagnetic shielding applications.

The invention relates to the technical field of wave-absorbing materials, and particularly discloses a CaMnO3 / CoNi composite wave-absorbing material and a preparation method thereof. The material takes dielectric loss type CaMnO3 as a matrix, and magnetic loss type CoNi nanoparticles are coated by a liquid phase reduction method to form a heterojunction composite structure. By regulating and controlling the mixing ratio of CaMnO3 to CoNi, the impedance matching characteristic of the material is obviously optimized, and the synergistic enhancement of dielectric loss and magnetic loss is realized. Experiments show that when the thickness of the material is 3.2 mm, the material reaches the minimum reflection loss of 26.6 dB at 8.48 GHz, the effective wave absorbing bandwidth reaches 4.09 GHz, and the performance of the material is obviously superior to that of a single CaMnO3 or CoNi material and a CaMnO3 / Co composite material. The method is simple in preparation process, low in cost and suitable for the fields of electromagnetic shielding, stealth technologies and the like.

The present application relates to the technical field of functional new material, and more particularly to a radio electromagnetic wave high-transmission infrared low-emissivity material and a preparation method thereof.The radio electromagnetic wave high-transmission infrared low-emissivity material has a reflection effect in the 2-20 mu m infrared band and a direct transmission effect in the 100 kHz-1.6 THz communication electromagnetic wave band.The radio electromagnetic wave high-transmission infrared low-emissivity material comprises a scattering body.The present application has the advantages of solving the problems of electromagnetic shielding effect and limited application of the existing low-emissivity material, simple preparation method, and application of the material in the fields of new energy vehicles, low-carbon energy-saving buildings, cold-chain logistics, low-carbon agriculture, smart cities, and infrared thermal camouflage of radiation heat insulation and compatible multi-band stealth technology, and has a good application prospect.

The invention belongs to the technical field of electromagnetic stealth, and discloses a frequency selective surface unit and a reconfigurable frequency selective surface. The frequency selection surface unit adopts a cascade unit structure of four metal layers and three dielectric layers, and a PIN diode, a feed connecting line, a square patch, a double-square-ring patch shaped like a Chinese character'hui ', a single-square-ring patch and the like are combined to form a filtering structure with good performance. According to the reconfigurable frequency selective surface, lower passband insertion loss, wider passband, better incident angle stability, narrower transition band, better out-of-band rejection and good polarization stability are achieved, and the problems that an existing reconfigurable frequency selective surface is insufficient in passband bandwidth, poor in out-of-band rejection and the like are solved. According to the reconfigurable frequency selective surface, the PIN diodes and the patch structures on all the units are connected through the metal feed connecting lines, so that after the array structure is formed, all the units can be fed only by feeding a certain unit, the design of an extra feed network layer is avoided, and the unit structure is simplified.

The invention relates to the technical field of terahertz metamaterial devices, in particular to a dynamic switchable broadband terahertz wave absorber based on vanadium dioxide. The insulator-metal reversible phase change characteristic of vanadium dioxide is utilized to realize effective regulation and control of the conductivity; through the innovative design of the top layer resonance pattern, the wave absorber achieves efficient wave absorption with the average absorption rate exceeding 90% at the frequency band of 5.9-12.4 THz in the vanadium dioxide metallic state, the absorption bandwidth is 6.5 THz, and the relative bandwidth is 71.6%. The wave absorber has quadruple rotational symmetry, polarization insensitivity and excellent oblique incidence stability, and the absorptivity of TE polarized waves within the incidence angle range of 0-60 degrees and the absorptivity of TM polarized waves within the incidence angle range of 0-40 degrees are both maintained to be 80% or above; the average absorptivity of vanadium dioxide in an insulation state is lower than 1%, and a dynamic switch with a wave absorbing function is realized. The device is simple in structure, high in design robustness and high in preparation feasibility, and can be widely applied to the fields of terahertz imaging systems, high-speed communication electromagnetic compatibility shielding, high-performance radar stealth technologies and the like.

The invention discloses a wide-angle stable ultrathin low-frequency wave absorber based on an electromagnetic metamaterial, and belongs to the technical field of artificial electromagnetic structures and radar stealth. A core of the wave absorber is of a multi-layer composite structure formed by a plurality of wave absorbing units which are periodically arranged in a hexagonal honeycomb shape in space, and each unit comprises a copper-based resonance layer etched with three curve narrow slits, an epoxy plate layer, a hexagonal patch layer, a high-molecular polymer layer and a conducting substrate layer from top to bottom. Through the special geometric configuration and the spatial alignment relationship of the resonance layer and the patch layer, and in combination with the lamination design of the sub-wavelength thickness (0.908 mm), efficient absorption with the reflection loss superior to-19.7 dB is realized at the low frequency of 0.21 GHz, and the relative thickness is as low as lambda 0 / 1573. The structure has excellent angle and polarization stability at the same time, the resonant frequency deviation is smaller than 5 MHz in the incidence range of 10-70 degrees, and the absorption performance is kept consistent in the full polarization range of 0-180 degrees. The invention effectively solves the problems of'thickness-performance 'contradiction and angle sensitivity of the traditional wave-absorbing material in a low-frequency band, and provides a high-performance solution for the fields of radar stealth, electronic countermeasure, electromagnetic compatibility and the like.

The invention relates to the field of electromagnetic metamaterials, stealth technology and weak target detection, and aims to solve the problem that the scattering cross section of a miniature platform with an extremely small geometric size is extremely low, and the miniature platform with the extremely small geometric size is difficult to effectively find and track by a traditional radar detection means. The invention discloses an electromagnetic scattering enhancement device with a stealth function and a weak target detection method, a coaxial nested structure is adopted, the electromagnetic scattering enhancement device sequentially comprises a balance dielectric cylinder, a sensing cavity for accommodating a to-be-detected object and a multi-layer dielectric shell from inside to outside, and through the electromagnetic and geometric parameter distribution design of the balance dielectric cylinder and the multi-layer dielectric shell, the sensing cavity is used for accommodating the to-be-detected object. The dual functions of no-load stealth and load amplification are achieved under the preset working frequency, a high-gain response mechanism for tiny disturbance is established through the balance dielectric cylinder, signal amplification of a weak target is achieved, and the robustness of compensating machining errors through parameter adjustment of the balance dielectric cylinder is achieved. The method can be widely applied to the fields of micro target detection, self-adaptive detection and safety protection.

The present application belongs to the field of infrared-laser stealth technology, and discloses a radar wave-transparent infrared-laser stealth film, which comprises, from bottom to top, a substrate, a photonic crystal multilayer film structure and a top surface patterning structure; the photonic crystal multilayer film structure is composed of two kinds of transparent medium materials with high and low refractive indexes alternately stacked and arranged; the top surface patterning structure is used for realizing surface phase control; by using the constructive interference effect of the photonic crystal multilayer film structure on the incident wave with a wavelength near a preset target wavelength, and cooperating with the top surface patterning structure, the reflected wave front can be controlled, and the vertical mirror reflection can be reduced. Based on the photonic crystal high-reflection multilayer film structure, by using the constructive interference effect and cooperating with the phase control pattern structure, the phase control reflected electromagnetic wave front can be controlled, so that the vertically reflected electromagnetic wave is deflected to other directions, the conversion from high mirror reflection to high scattering of 8-14 mu m infrared waves can be realized, and the mirror reflection is inhibited.

The application relates to a method for characterizing the RCS of a heterogeneous target passive scattering, belonging to the technical field of radar and communication. Firstly, the method judges the target surface roughness type based on the Rayleigh criterion, reveals the electric wave propagation mechanism of electromagnetic wave interaction with the target, and constructs an RCS model in combination with the target scattering characteristics. Then, in combination with the target passive scattering characteristics and the bistatic radar equation, the RCS radiation direction mode caused by the target passive scattering is characterized. Then, the three-dimensional structure model is reconstructed by using the target electromagnetic parameters, and the RCS data under different frequency bands and incident angles are obtained through full-wave simulation and microwave darkroom measurement. Finally, the simulation data and the measured data are used to fit the normalized radiation direction mode, the RCS model parameters are determined, and the accuracy and effectiveness of the model are verified. The method effectively combines theoretical analysis and simulation technology, can accurately and efficiently characterize the passive scattering characteristics of a heterogeneous target, and provides strong support for the development of radar detection and stealth technology.

This invention discloses a large-angle broadband electromagnetic absorber based on the reciprocity principle and a metal-free floor structure, belonging to the field of electromagnetic stealth technology. The electromagnetic absorber of this invention includes several vertically placed, rectangularly arranged absorbing structural units and several horizontally placed, rectangularly arranged absorbing suppression units. In this electromagnetic absorber, the absorbing structural units are vertically placed above the absorbing suppression units; the absorbing structural units are used to absorb electromagnetic waves incident at large angles; the absorbing suppression units serve to minimize the transmission coefficient and achieve impedance matching; this structure can absorb high-frequency, large-angle incident electromagnetic waves outside the band while ensuring the transmission of low-frequency, normally incident electromagnetic waves within the band.

The application provides an anti-icing and drag-reducing stealth patch, a preparation method thereof and an aircraft, and relates to the field of stealth technology.The anti-icing and drag-reducing stealth patch comprises, from bottom to top, a substrate layer, a heating layer and a super-smooth drag-reducing layer, wherein the heating layer is composed of a glass fiber cloth layer connected to the substrate layer and a graphene layer distributed in an island-like network on the glass fiber cloth layer, the super-smooth drag-reducing layer is composed of a polydimethylsiloxane coating layer and silicon oil injected into the polydimethylsiloxane coating layer, and a plurality of drag-reducing micro-grooves are arranged on the super-smooth drag-reducing layer in an interval manner.The application can realize the functions of radar wave penetration, anti-icing and drag reduction, can be used in harsh environments, and can meet the use requirements of civil and military aircrafts.

This invention belongs to the field of electromagnetic metasurface technology, specifically disclosing an RCS-reduced circularly polarized metasurface antenna for C-band satellite communication. It comprises, from top to bottom, a first metasurface layer, a first dielectric layer, a second metasurface layer, a second dielectric layer, a slotted metal plate, a third dielectric layer, and a feed antenna layer. The first metasurface layer consists of four sets of unit structures arranged mirror-image each other in a two-dimensional direction, with two types of square chamfered patches arranged non-contactly in each set. The second metasurface layer also consists of four sets of unit structures arranged mirror-image each other in a two-dimensional direction, with L-shaped resonant rings arranged in an array in each set. The total number of square chamfered patches and L-shaped resonant rings is the same, with an L-shaped resonant ring located below each square chamfered patch. This antenna is suitable for satellite communication, can reduce the radar cross-section in the 4-10.5 GHz range, and has significant application value in electromagnetic stealth technology.

The application discloses a carbon-based superstructure integrated with wave-absorbing stealth and electric heating deicing and a preparation method thereof, and belongs to the field of functional composite materials and aerospace stealth technology. The carbon-based superstructure comprises a substrate layer and a periodic array structure on the top surface of the substrate layer. The periodic array structure comprises a plurality of superstructure units. Each superstructure unit comprises a cylindrical dielectric layer and a circular-truncated-cone wave-absorbing layer which are alternately stacked from bottom to top, and the two are alternately stacked to form a multi-stage impedance gradient junction. The application combines machine learning to accurately optimize the geometric parameters of each layer in the superstructure unit, so that the superstructure realizes efficient wave absorption in a super-wide frequency range of 2-40 GHz (the bandwidth of the reflection loss lower than -20 dB is significantly widened), and still maintains excellent stealth performance under large-angle incidence (greater than 45 degrees). Meanwhile, the superstructure has efficient and rapid electric heating deicing capacity, and solves the problems that the traditional aviation materials are difficult to be compatible with stealth and deicing functions, and have poor large-angle stealth performance.

The invention belongs to the technical field of infrared stealth, and particularly relates to a multiband infrared stealth curtain and application thereof. The infrared stealth material provided by the invention comprises a flexible substrate; the metal coating is arranged on one surface of the flexible substrate; the infrared stealth film is arranged on the other surface of the flexible substrate; the infrared stealth thin film is of a multi-layer film structure. The average emissivity of the infrared stealth film in the wave band of 3-5 microns is smaller than or equal to 0.15, the average emissivity in the wave band of 8-14 microns is smaller than or equal to 0.15, and the average emissivity in the wave band of 5-8 microns is larger than or equal to 0.7. The infrared stealth material provided by the invention is used as a curtain of a vehicle air inlet and has the characteristics of preventing radiation heating of an air inlet device and selective low infrared emissivity, so that the infrared stealth material has a relatively low infrared characteristic and is not easily found by infrared equipment of an opposite side, a good infrared stealth function is realized, and the service life of the infrared stealth material is prolonged. The method is of great significance in improving the battlefield viability of the vehicle.