36results about How to "Improve electromagnetic shielding performance" patented technology

A highly integrated wide- and narrow-band RF transceiver module includes a housing made of aluminum alloy with a flat structure. An upper cavity is formed with an opening on the housing's surface, and a lower cavity is formed with an opening on the lower surface of the housing. An upper control card and an upper partition are located at the bottom of the upper cavity, with the upper partition fixed to the bottom of the upper cavity by screws. Multiple compartments are formed on the upper partition. An upper cover is fixed to the upper end of the upper cavity. A lower control card and a lower partition are located at the bottom of the lower cavity, with the lower partition located below the lower control card and fixed to the bottom of the lower cavity. Multiple holes are formed on the lower partition, with electronic components on the lower control card located within each hole. A lower cover is fixed to the lower end of the lower cavity. This invention's dual-cavity design evenly distributes the gain in the RF link across both sides, achieving physical isolation and increasing electromagnetic shielding. Simultaneously, power amplifiers and RF front-end circuits arranged on the same side are physically isolated through the upper and lower partitions, ensuring electromagnetic shielding effectiveness.

The invention discloses a bamboo charcoal fiber cloth-based composite material as well as a preparation method and application thereof, and belongs to the technical field of electromagnetic shielding materials. The bamboo charcoal fiber cloth-based composite material comprises: a base cloth, which is a bamboo charcoal fiber cloth subjected to oxidation modification and activation treatment by TEMPO (2, 2, 6, 6-tetramethylpiperidine-1-oxygen radical); the gradient copper layer is chemically plated on the surface of the base cloth; the nickel layer is chemically plated on the surface of the gradient copper layer; wherein the density of the base cloth side copper layer is smaller than that of the nickel layer and the copper layer. The bamboo charcoal fiber cloth is subjected to surface treatment modification through a special process, and meanwhile, a gradient copper layer and a gradient nickel layer are formed on the surface of the bamboo charcoal fiber cloth, so that the bamboo charcoal fiber cloth-based composite material with light weight, structural stability and excellent electromagnetic shielding performance is prepared, and the requirements of flexible and broadband electromagnetic shielding application are met.

The utility model belongs to the technical field of shielding cabinets, particularly relates to a portable shielding cabinet made of lightweight composite materials, and aims to solve the problems that a main body structure of an existing device is integrally made of metal materials, and although the metal materials have excellent electromagnetic shielding performance, the self weight of the metal materials is large, so that in a scene needing frequent movement or temporary construction, the electromagnetic shielding performance of the metal materials is poor. In order to solve the problems that a traditional shielding cabinet is extremely inconvenient to carry and consumes a large amount of manpower and material resources, the utility model provides the following scheme that the portable shielding cabinet made of the lightweight composite material comprises a frame main body which adopts a frame type structure; the utility model has the beneficial effects that the frame main body is formed by splicing high-strength aluminum alloy sections, the density is low, the weight is light, the frame type structure is matched, the frame is stable, the portability is obviously improved, the carrying is easy and labor-saving, the corner connecting pieces are made of high-strength engineering plastics, the weight is reduced, electromagnetic conduction is prevented, and the shielding performance is optimized.

The invention discloses a planar integrated hollow rectangular dielectric waveguide, and relates to the field of planar integrated waveguides, and the planar integrated hollow rectangular dielectric waveguide comprises an upper dielectric layer, a middle dielectric layer and a lower dielectric layer which are distributed from top to bottom, and a metal ground plane attached to the lower surface of the lower dielectric layer. The left side air hole area, the middle wave guide area and the right side air hole area are distributed from left to right; the middle wave guide region is provided with an air slot in the center of the middle dielectric layer to form a hollow wave guide structure; a plurality of columns of air holes penetrating through the upper dielectric layer, the middle dielectric layer and the lower dielectric layer are formed in the left air hole area and the right air hole area, and an air hole array is formed. The planar integrated hollow rectangular dielectric waveguide designed by the application has the advantages of low loss, easy realization of integrated design and planar integration, and simple and stable structure.

This invention provides a film that combines thermal conductivity, thermal insulation, and electromagnetic shielding. It includes a high thermal conductivity film, a phase change film, and a thermally insulating electromagnetic shielding film. The high thermal conductivity film and the thermally insulating electromagnetic shielding film are respectively disposed on both sides of the phase change film. The thickness of the high thermal conductivity film is 0.01–0.5 mm; the thickness of the phase change film is 0.1–1 mm; and the thickness of the thermally insulating electromagnetic shielding film is 0.05–1.5 mm. This invention, combining thermal conductivity, thermal insulation, and electromagnetic shielding, can effectively solve the problem of poor heat dissipation in electronic devices such as mobile phones under high load, while reducing the impact of electromagnetic radiation on users. The product is lighter, thinner, and more flexible; the entire film product can be completely folded without material breakage.

The application relates to the technical field of mechanical arms, in particular to a high-integration-degree mechanical arm joint module which comprises a control unit, a coding unit, a core driving unit, a speed reduction unit, a bearing unit, a torque feedback unit, a crankshaft and a shell assembly; the bearing unit comprises a bearing inner ring, a bearing outer ring, steel balls and a sealing ring which are coaxially arranged, the bearing inner ring is provided with an outer groove matched with the steel balls on an outer wall, and the bearing outer ring is provided with an inner groove corresponding to the outer groove on an inner wall; the bearing inner ring is provided with an inner ring clamping groove for clamping the sealing ring at a position close to an end portion, and the bearing outer ring is provided with an outer ring clamping groove corresponding to the inner ring clamping groove at a position close to an end portion. The application has the effects of realizing the synergistic optimization of high torque density and low friction loss in a limited space, reducing the volume of a sealing structure and improving the integration degree of the module.

The present invention provides an environmental testing device, comprising: a heat-insulating chamber which includes a test chamber and is formed by an electrically conductive heat-insulating plate; an air conditioner; the heat insulation chamber comprises a chamber main body with an entrance and an exit and a door body for opening and closing the entrance and the exit, the heat insulation plate forming the chamber main body comprises an outer plate and an inner plate arranged on the inner side of the outer plate, and the air supply fan is used for generating air flow enabling the air conditioned by the air conditioner to flow into the test chamber. A heat insulation plate forming a chamber main body and a heat insulation plate forming a door body are connected in a mutually electrically conductive manner, and the heat insulation plate forming the chamber main body is provided with an opening through which at least one of a shaft of an air blower and a part of a component forming an air conditioner is inserted. And a shield box which is attached to the insulation plate having the opening so as to cover the opening from the outside of the insulation chamber, is electrically conductive to the insulation plate, is formed of an electrically conductive member, and defines a space by the shield box and the insulation plate having the opening.

The present application relates to the technical field of aerated concrete preparation, and particularly relates to a method for preparing electrically conductive aerated concrete by using porous carbonized recycled aggregate and the aerated concrete. The process method first places pre-wetted recycled aggregate in a pressurized carbonization kettle, and industrial waste gas with CO2 concentration greater than or equal to 20% is introduced to react for 2-3 hours at 0.5-0.7 MPa and 60-70 DEG C to produce porous carbonized recycled aggregate. Then the porous carbonized recycled aggregate is dry-mixed with gel material, gypsum, conductive carbon black and reinforcing fibers, and then mixing water containing water reducing agent (water aggregate ratio 55-60%) is added to stir into base mortar. Then aluminum paste suspension is added to the mortar, and after stirring to start aeration, the mortar is poured into a mold. After 2-3 hours of static aeration, the mold is finally autoclaved and dried for 6-8 hours to obtain the electrically conductive aerated concrete. Through aggregate pretreatment strengthening, orderly dispersion of the conductive phase and hierarchical curing control, the present application can effectively solve the contradiction between light weight, high strength, electrical conductivity and durability, and provide a multifunctional green building material solution for airport construction.

This disclosure provides an electromagnetic shielding structure and a method for fabricating such a structure, relating to the field of semiconductor packaging technology. The electromagnetic shielding structure includes a substrate, a first electronic device, a shielding barrier layer, a reinforcing shielding layer, a molding compound, and a metal layer. A grounding pad is provided on the substrate. The first electronic device is disposed on the substrate and electrically connected to it. The first electronic device is located within the barrier area enclosed by the shielding barrier layer. The shielding barrier layer has corner portions. The reinforcing shielding layer is disposed at the corner portions and electrically connected to the grounding pad. The molding compound is disposed on the substrate and covers the first electronic device, the shielding barrier layer, and the reinforcing shielding layer. The metal layer is disposed on the molding compound and electrically connected to both the shielding barrier layer and the reinforcing shielding layer. This structure provides good electromagnetic shielding and effectively prevents noise interference.

The utility model relates to a middle connecting plate of a transmission, the transmission and a vehicle, and the middle connecting plate comprises a middle connecting plate body which is provided with a first shaft through hole and a second shaft bearing mounting hole; the first valve plate and the middle connecting plate body are integrally formed, the first valve plate is provided with a first surface, a plurality of oil cavities are formed in the first surface, and the first valve plate is in surface-to-surface fit with the second valve plate. The first valve plate is integrated on the middle connecting plate body, so that the integration level can be improved, and the lengths of the middle connecting plate and the second valve plate in the thickness direction can be shortened; an oil cavity is adopted to replace a slender oil duct, the oil cavity is small in depth, large in size area, better in castability than the oil duct and good in product casting quality, the first valve plate and the second valve plate are matched in a face-to-face mode, the leakage risk is reduced, the number of the oil ducts in the middle connecting plate body is reduced, and the space occupied by auxiliary holes and a plugging structure and the number of plugging parts can be reduced; the overall dimension of the middle connecting plate is reduced, product cost is reduced, and reliability is improved.

The invention belongs to the technical field of electronic circuit design, and discloses a differential signal Fanout structure for improving the integrity of a high-speed signal, and the structure comprises a PCB substrate; the differential signal pair is arranged on the PCB substrate, the differential signal pair comprises a P signal wire and an N signal wire, and the P signal wire and the N signal wire are respectively used for connecting chip pins; and a ground shield unit. By adopting layered fan-out and large-spacing decoupling design, crosstalk of high-speed differential signals is remarkably reduced, the limitation that tight coupling wiring must be conducted on the same layer in a traditional Fanout structure is broken through, P signals and N signals are arranged on the surface layer and the inner layer of a PCB respectively, and therefore the signal transmission efficiency is improved. By means of isolation of a vertical space, maximization of horizontal projection spacing is achieved (a decoupling spacing area is formed), inter-line coupling capacitance is remarkably reduced, far-end crosstalk is remarkably reduced through the structure, and the signal-to-noise ratio and eye pattern opening of a high-speed link are improved.

The application relates to a microwave circuit band-stop filtering device based on an artificial magnetic conductor, and belongs to the fields of artificial magnetic conductors and filtering technologies, which solves the problem that a microstrip line causes electromagnetic interference on a circuit board and the surrounding environment in the prior art. The device comprises a shell and a microwave circuit board; the microwave circuit board is arranged in the shell, and a microstrip line is arranged on the microwave circuit board; an artificial magnetic conductor array is arranged on the lower surface of the top cover of the shell, the artificial magnetic conductor array is formed by arranging a plurality of same artificial magnetic conductor structure units, and is used for filtering electromagnetic interference caused by the microstrip line. The microwave circuit band-stop filtering device based on the artificial magnetic conductor is realized.

The utility model relates to the field of joints, in particular to a detachable and replaceable two-joint joint, which comprises a plug main body, a cable and a wall bushing, two groups of plug main bodies are transversely arranged, a wall bushing is arranged between the two groups of plug main bodies, and cables are arranged between the wall bushing and the plug main bodies; according to the utility model, by replacing the common nut on the plug main body, after the plug main body is inserted into a socket, current or signals are conducted from the socket to the cable connected with the plug main body through the plug main body and then are transmitted to equipment or a system needing power supply or signal receiving through the cable, and in the process, the wall bushing ensures the safety and the stability of the cable; according to the detachable plug, the cable is prevented from being damaged by external factors, normal operation of a whole circuit system is guaranteed, connectors of different materials, specifications or functions can be replaced through the detachable plug body according to different working environments, medium transmission requirements or equipment connection requirements, meanwhile, timely cleaning is facilitated, transmission efficiency is maintained, and the service life of equipment is prolonged.

The embodiment of the invention provides a corrosion-resistant electromagnetic shielding material and a preparation method thereof, the corrosion-resistant electromagnetic shielding material is of a layered structure, and the corrosion-resistant electromagnetic shielding material sequentially comprises a conductive layer, an epoxy wave-absorbing layer and a first corrosion-resistant layer. The first corrosion-resistant layer comprises polyphenylene sulfide resin, epoxy fluorosilane modified graphene, polyether-ether-ketone resin and a dispersing agent. According to the corrosion-resistant electromagnetic shielding material provided by the invention, the polyphenylene sulfide resin is adopted as a matrix and has excellent corrosion resistance, the polyether-ether-ketone resin can improve and relieve the brittleness of the polyphenylene sulfide resin, and meanwhile, the epoxy-fluorosilane modified graphene can construct a continuous conductive network to assist in improving the electromagnetic shielding effectiveness; the graphene sheet layer can form a physical barrier network in a polyphenylene sulfide matrix, corrosion medium permeation is blocked, the corrosion resistance is further improved, a covalent bond can be formed between the epoxy group and the epoxy wave-absorbing layer, the interlayer binding force is improved, and the service life of equipment is prolonged.

The utility model relates to tensile resistance structure technical field, especially a kind of tensile resistance structure of AI display shield extension cord, including outer sheath layer and reinforcing rib, the outer surface of reinforcing rib is fixedly connected with several linear array's connecting ring, the inner wall of several connecting rings is rotatably connected with an inner sheath layer, the inner wall of inner sheath layer is sleeved with conductor.The utility model has the advantages of: by optimization design and material selection, the tensile effect and service life of cable are significantly improved.First, reinforcing rib adopts glass fiber material, with high strength and high-temperature resistance, can effectively disperse tension, prevent cable from breaking when stressed.Reinforcing rib outer surface fixedly connected connecting ring adopts polyethylene material, with good flexibility and wear resistance, by with the limiting groove of inner sheath layer outer surface rotatably connected, the relative sliding between reinforcing rib and inner sheath layer is significantly reduced, avoid the abrasion and structural looseness caused by sliding.

The application provides a non-radio frequency piezoelectric acoustic device and earphone. The non-radio frequency piezoelectric acoustic device comprises a substrate, an insulating layer and a piezoelectric functional layer. The substrate is made of a low-resistance material, so that the loss of the non-radio frequency piezoelectric acoustic device during operation can be effectively reduced. The substrate with low resistivity has a large number of free carriers. When the electric field in the piezoelectric functional layer changes, the free carriers can quickly respond and move to form effective mirror charges, which can play a good electromagnetic shielding effect, reflect the energy back to the piezoelectric functional layer, and prevent the energy from leaking and dissipating to the deeper and farther substrate.

This invention discloses a bamboo charcoal fiber cloth-based composite material, its preparation method, and its application, belonging to the field of electromagnetic shielding materials technology. The bamboo charcoal fiber cloth-based composite material comprises: a base fabric, wherein the base fabric is a bamboo charcoal fiber cloth that has been oxidized and activated by TEMPO (2,2,6,6-tetramethylpiperidine-1-oxy radical); a gradient copper layer electroplated on the surface of the base fabric; and a nickel layer electroplated on the surface of the gradient copper layer; wherein the density of the copper layer on the base fabric side is less than that of the nickel layer and the copper layer. By performing a special process to modify the surface of the bamboo charcoal fiber cloth, and simultaneously forming a gradient copper layer and a nickel layer on its surface, a bamboo charcoal fiber cloth-based composite material with lightweight properties, structural stability, and excellent electromagnetic shielding performance is prepared to meet the needs of flexible and broadband electromagnetic shielding applications.

The application provides an electromagnetic shielding packaging structure, which comprises a lead frame with a base island and a pin; a chip structure arranged on the surface of the base island; a plastic packaging layer arranged on the surface of the lead frame and covering the chip structure, wherein a first step groove is formed on the surface of the plastic packaging layer close to the lead frame, and the bottom surface of the first step groove is a certain distance away from the pin of the lead frame; an electromagnetic shielding layer arranged on the surface of the first step groove; an electromagnetic shielding wire arranged on the side of the chip structure away from the lead frame, and the electromagnetic shielding wire is electrically connected with the electromagnetic shielding layer; and a grounding wire, the two ends of the grounding wire are electrically connected with the electromagnetic shielding layer and the grounding pin respectively. Through the structure, the electromagnetic shielding structure can be formed by wire bonding in the lead frame packaging structure, and the electromagnetic shielding wires do not need to be grounded by direct contact, which can greatly reduce the wire bonding difficulty of the electromagnetic shielding wires.

The utility model discloses a signal module and connector, and the connector includes support frame and a plurality of signal modules, and the signal module includes insulating seat, a plurality of terminals inserted into the insulating seat and adapter plate, the insulating seat includes base, docking portion, the positioning wall of protruding out of the base, the base is provided with a plurality of positioning blocks that are arranged in sequence and are spaced, and the insulating seat is provided with mounting structure, each terminal includes welding section, and the welding section of each terminal is embedded in the interval between each adjacent positioning block respectively, the adapter plate is provided with a plurality of through -holes for each welding section respectively inserted, and the welding section is electrically connected with the adapter plate through welding, and the mounting structure is connected with the adapter plate to guide the welding section to insert into the through -hole, the terminal and the adapter plate are positioned and installed in the insulating seat, and the welding section can be positioned and kept in the through -hole even if not welded with the through -hole, so that the welding section does not come out from the through -hole when assembling other components, realizes that each component is connected and is carried out one -time welding uniformly, and improves processing efficiency.

The utility model provides a photoelectric isolation 16-port concentrator with a built-in power supply, and relates to the technical field of network communication equipment. The hub comprises a shell, wherein a mounting cavity is formed in the shell to accommodate each component; the power supply module is fixed on one side of the bottom of the mounting cavity and provides power for the concentrator; the photoelectric isolation module is arranged above the power supply module at intervals through an insulating bracket to realize a photoelectric isolation function; the port group comprises 16 RJ45 interfaces, odd-numbered ports are inclined upwards, and even-numbered ports are inclined downwards, so that connection is facilitated; the heat conduction structure effectively dissipates heat; and the shielding structure enhances the electromagnetic shielding effect. In addition, heat dissipation fins are arranged on the side wall of the shell, heat dissipation grids are arranged on the top of the shell, and the heat dissipation performance is further improved. The concentrator solves the technical problem of contradiction among high-density port layout, multi-module heat dissipation requirements and multi-band electromagnetic interference collaborative suppression in a compact space, and achieves the effect of synchronously optimizing heat dissipation efficiency and electromagnetic interference suppression in the compact space.

The application discloses a cable connector, which comprises an insulating seat, a first terminal array, a second terminal array, a metal shell and a cable; the insulating seat is provided with a support platform; the first terminal array and the second terminal array each comprise at least one pair of differential signal terminals and ground terminals; the cable comprises a core wire group, and the core wire group comprises signal conductors and ground conductors; wherein a plurality of accommodating grooves are arranged between the first terminal array and the second terminal array; the signal conductors are electrically connected to the differential signal terminals on one side of the support platform; and the ground conductors are bent into one of the accommodating grooves and are electrically connected to the ground terminals on the other side of the support platform. The ground conductors are directly arranged on the lateral sides of the differential signal terminals, thereby improving the electromagnetic shielding effect between two adjacent pairs of differential signal terminals, improving the electromagnetic shielding effect of the first terminal array and the second terminal array, reducing the electromagnetic interference in the signal transmission process, and ensuring the stability of high-frequency signal transmission.

The present application relates to the technical field of polyvinyl chloride foam material preparation, and particularly relates to a polyvinyl chloride electromagnetic shielding foam material and a preparation method thereof, wherein polyvinyl chloride resin, diisooctyl phthalate, magnesium hydroxide, copper-plated Mxene, light calcium carbonate, a heat stabilizer, a light-proof agent and a lubricant are uniformly mixed according to a certain weight ratio, and then are mixed by using a high-temperature mixing machine, and then are subjected to mold pressing to obtain a PVC composite material forming sample; the PVC composite material forming sample is added into a barrel of a conical twin-screw extruder, is subjected to extrusion forming, is subjected to pre-stretching, and then is subjected to foaming treatment to obtain the polyvinyl chloride electromagnetic shielding foam material. After the pre-stretching process, the polyvinyl chloride electromagnetic shielding foam material is obtained, the cell morphology in the polyvinyl chloride electromagnetic shielding foam material has a certain orientation along the stretching direction, the cell size is large, the specific surface area of the cells is increased, and the electromagnetic shielding performance of the material is improved.

The utility model discloses a kind of composite motion cables for machine dog leg part. The composite motion cable outer diameter is less than 8mm, composite core wire is mainly composed of two insulated core wires and is covered with aluminum foil layer, tinned copper foil silk braided shielding layer is covered outside four composite core wires, at least one power line is arranged outside tinned copper foil silk braided shielding layer, cotton thread is arranged outside tinned copper foil silk braided shielding layer, tape layer is covered outside tinned copper foil silk braided shielding layer, power line and cotton thread. The outer surface of tape layer is covered with outer sheath. The utility model has good flexibility, wear resistance, signal transmission stability and anti-interference, and can meet the demand of machine dog leg complex motion.

The present application belongs to the technical field of laminated composite materials, and specifically discloses a basalt fiber laminated plate and a preparation method thereof, which comprises n layers of basalt fiber layers, a group of electromagnetic shielding components and two groups of damage positioning components; the electromagnetic shielding component comprises at least one layer of a first LIG film layer, the first LIG film layer and the basalt fiber layer have the same size; the first LIG film layer is inserted into the laid basalt fiber layer; each group of damage positioning components comprises m groups of second LIG film layers, and the lateral spacing c of one group of damage positioning components is arranged in parallel into the basalt fiber layer; the longitudinal spacing c of the other group of damage positioning components is arranged in parallel into the basalt fiber layer; the two groups of damage positioning components and the first LIG film layer are respectively located in different layers of the basalt fiber layer. The present application can improve the electromagnetic shielding efficiency and the damage positioning capability while maintaining the interlaminar fracture toughness of the basalt fiber laminated plate.

An electrical connector includes an insulating body, at least one row of terminals, multiple inner grounding plates, and multiple outer grounding plates. The insulating body has a mating groove. The row of terminals includes multiple signal terminal pairs, each signal terminal pair including two adjacent signal terminals. Each signal terminal includes a fixing part, a signal elastic arm, and a signal foot. The signal elastic arm has a signal contact part protruding into the mating groove. Each outer grounding plate extends two grounding elastic arms, each grounding elastic arm having a ground contact part protruding into the mating groove. The two grounding elastic arms are located on both sides of the corresponding two signal elastic arms. Each inner grounding plate extends two overlapping arms and two grounding feet. The two grounding feet are located on both sides of the two signal feet, and each overlapping arm abuts against the corresponding grounding elastic arm. The inner and outer grounding plates of this invention can expand the grounding effect, improve electromagnetic shielding capability, and adapt to higher frequency resonant signals.

The utility model relates to an electric drive system shell, electric drive system and vehicle, include: electric control shell is equipped with the partition, the partition is in the electric control shell and is divided into first cavity and second cavity, and the partition is equipped with first power module installation platform, and first power module installation platform is located in the first cavity, motor shell is connected with electric control shell, and the motor shell cover is located in the first cavity, the cover plate is connected with electric control shell, and the cover plate cover is located in the second cavity. The utility model embodiment's electric drive system shell's coupling degree between motor shell and electric control shell is lower, and production and maintenance are relatively simple, can reduce cost.

The application discloses a kind of combined mutual inductor precision test's calibrating device, including test shell, mounting plate and heat dissipation mechanism;Test shell: its bottom wall is fixedly connected with heat conduction plate, and the fin lower end between heat conduction plate is provided with heat dissipation pipeline, and the upper surface of heat conduction plate is fixedly connected with booster;Mounting plate: its fixed connection is in the upper end of mounting bracket of heat conduction plate, and the upper surface of mounting plate is provided with resistance voltage divider and current sensor;Heat dissipation mechanism: it includes shell, heat exchange fin and heat exchange pipeline, the shell is placed in the left side of test shell, and the inside of shell is fixedly connected with heat exchange fin, and the fin between heat exchange fin is fixedly connected with heat exchange pipeline, and the water inlet two of heat exchange pipeline lower end is connected with the water outlet one of heat dissipation pipeline, this combined mutual inductor precision test's calibrating device, by the heat dissipation mode of full-closed type is for the element inside test shell high heat and is dissipated heat, with better electromagnetic shielding effect, more accurate.

The invention provides a multi-spectrum compatible camouflage and protection film and a preparation method thereof, and belongs to the technical field of camouflage films, and the method comprises the following steps: screening and determining a phase change functional layer material and a directional emission module material; coupling a directional transmitting module material, a phase change functional layer material and a mechanical protective layer material, constructing a Fabry-Perot resonant cavity type multilayer film structure, and calculating an initial thickness range of each layer of material in the directional transmitting module; carrying out parametric scanning by taking the initial thickness range of the optical spacing layer material as a variable, calculating the transmittance and the directional emissivity of the multi-layer film in a middle and far infrared band, and determining the optimal thickness of each layer of film at the same time; and according to the structure of the multi-layer film and the optimal thickness of the multi-layer film, sequentially depositing each layer of film material on the substrate by adopting a magnetron sputtering process to obtain the multi-spectrum compatible camouflage and protection film. The thin film in the scheme has dynamic infrared camouflage, efficient electromagnetic shielding, thermal management performance and mechanical protection performance.

This invention provides a magnesium-lithium-based composite material and its preparation method, belonging to the technical field of magnesium-based composite materials. The magnesium-lithium-based composite material provided by this invention comprises alternating layers of a first magnesium-lithium alloy layer, a second magnesium-lithium alloy layer, and a third magnesium-lithium alloy layer. The first magnesium-lithium alloy layer comprises, by mass percentage, 2-5.7% Li and the balance Mg; the second magnesium-lithium alloy layer comprises, by mass percentage, 10.3-16% Li and the balance Mg. In this invention, the matrix structure of the first magnesium-lithium alloy layer is an α-Mg single phase, and the matrix structure of the second magnesium-lithium alloy layer is a β-Li single phase, arranged in a sandwich structure of α-Mg / β-Li / α-Mg. This integrates the high-strength α-Mg phase with the high-plasticity β-Li phase, utilizing the impedance mismatch effect of the two different matrix phases to improve the electromagnetic shielding performance of the magnesium-lithium-based composite material.

The utility model provides a kind of integrated circuit board, comprising: electrically conductive patch group, measured integrated circuit, drive circuit and circuit;Measured integrated circuit and drive circuit are respectively arranged on the first surface and the second surface of circuit board;Drive circuit connects the drive end of integrated circuit;Measured integrated circuit is arranged on the working area of first surface, and electrically conductive patch group is arranged at the magnetic flux leakage of first shielding area of first surface, and / or the magnetic flux leakage of second shielding area.The utility model also provides a kind of electromagnetic testing device, comprising: integrated circuit board and electromagnetic wave chamber, integrated circuit board is based on first shielding area and is arranged on the test window of electromagnetic wave chamber.The utility model can well exclude the interference of electromagnetic noise, and utilize the easily obtained advantages of electrically conductive patch, save time and cost, without affecting the original working state of measured integrated circuit.