221results about How to "Good wave permeability" patented technology

The invention relates to a glass steel radar cover single element and a forming method thereof. The radar cover single element is a spherical body, the periphery of which is provided with a sewing structure, wherein the spherical body is formed by assembling the inner skin and the outer skin of the glass steel with a foam core layer and the foam core layer is formed by solidifying injected polyurenthane foam glue material. The forming method comprises the following steps of: presetting a fundamental mould, and copying the female mould and the male mould of the glass steel with the same curvature based on the fundamental mould; respectively manufacturing the inner skin and the outer skin of the radar cover single element on the inner surfaces of the female mould and the male mould of the glass steel; and merging the moulds, and forming an inner cavity between the inner skin and the outer skin. The invention is characterized in that the inner skin is provided with a plurality of through holes which enter into the inner cavity; and the inner cavity is filled with polyurenthane foam glue material from the outside to the inside by the through holes and is solidified to be a foam core layer. The method has simple operation, effectively reduces the use waste of polyurenthane foam, has low cost, guarantees the consilient thickness of the inner skin and the outer skin, and can assemble the radar cover with good safety, reliability and wave permeability.

The invention discloses a fiberglass radome modified by glass beads, which reduces the DK value thereof, and improves the wave penetration performance of the products. The fiberglass radome modified by glass beads is prepared by the following raw materials in weight portion: 100 portions of unsaturated polyester, 2-10 portions of glass beads, 0.5-2 portions of mold release agent, 0.5-2 portions of curing agent and 0.5-2 portions of accelerator.

The invention relates to a composite fiber automobile interior board and a production method thereof. The automobile interior board comprises a base layer and a non-woven or woven surface layer which is laminated on the at least one surface of the base layer, wherein the base layer consists of the following composite fibers: first fibers, namely polylactic acid fibers, second fibers, namely bastose selected from at least one of jute fibers, sisal fibers, ramie fibers, linen fibers, hemp fibers and kenaf fibers, and third fibers, namely basalt fibers in a weight percentage ratio of (20-70):(10-60):(10-60); and the surface layer consists of polylactic acid fibers. The composite fiber automobile interior board can be made into a three-dimensional deep drawing high-strength automobile interior board, and is safe, firm and environment-friendly when used as the base material of an automobile door inner board and a ceiling.

The invention relates to a method for producing a complex-shaped porous silicon nitride ceramic product. The method includes: using Si3N4 powder, Si powder, sintering auxiliaries, pore forming agent and silica sol to prepare mixed slurry; producing a male die with an outer surface identical with the appearance and size of the inner cavity of the product, and coating paraffin on the surface of the die; soaking the die into the slurry to allow the slurry to be adhered to the surface of the die, and then spraying Si3N4 coarse powder to the surface of the die to allow a layer of Si3N4 coarse powder to be evenly adhered to the slurry adhered to the surface of the die; drying the die in a ventilated environment for 1-3 hours to consolidate and harden the slurry on the surface of the die; repeating the soaking, spraying and drying process for multiple times until the thickness of the outer powder layer of the die meets the requirement; placing the die into an oven to melt the paraffin so as to separate a ceramic green body from the die; performing nitridation sintering on the green body to obtain the porous silicon nitride ceramic product. The bending strength of the porous silicon nitride ceramic product produced by the method is not lower than 50MPa, and the porous silicon nitride ceramic product is good in wave transmission performance.

The invention provides a double-layer allotype surface cement-based absorption material and a preparation method thereof, which relate to the cross technology field of electromagnetism and material science. Cement is adopted as a matrix, polystyrene foam and pulverized fuel ash are adopted as admixtures, an appropriate microwave absorption agent is compounded, and the obtained double-layer allotype surface cement-based absorption material is low in cost, energy saving and environmentally-friendly; a traditional panel material is subjected to surface shape designs such as a double-layer shape, a triangular shape, a sinusoidal shape, a semicircular shape and a right-angle groove shape, so that a series of double-layer allotype surface cement-based absorption material with a favorable electromagnetic absorption performance is prepared, the density and the thickness are small, the effective absorption bandwidth smaller than -10dB within the range of 1.7 to 18GHz is 13GHz or more, and the minimum reflectance is less than -30dB.

The invention provides a preparation method of a high-temperature wave-transparent composite material toughened by hybrid-woven fibers. The preparation method comprises the following steps: (1), weaving boron nitride fibers, high silica fibers and quartz fibers into prefab forms in a hybrid manner by virtue of a weaving method or a knitting method, wherein the prefab types are 2.5-dimensional or 3-dimensional forms; (2), mixing phosphoric acid in a certain mass fraction with aluminum hydroxide, adding deionized water and sufficiently stirring until mixing uniformly, and standing for 2 hours-4 hours to prepare aluminum phosphate sol; (3), placing fiber prefabs in the prepared aluminum phosphate sol, and sufficiently impregnating; (4), placing the fiber prefabs impregnated by the aluminum phosphate sol into an oven for carrying out a thermal-treatment drying process; (5), placing a dried composite material at 700 DEG C-900 DEG C for sintering and treating for 1 hour-2 hours; and (6), repeating the processes in step (3) to step (5) for 5-7 times to prepare the compact composite material. According to the invention, the technical process is relatively simple, easy to operate and low in cost; and the prepared composite material has very good high temperature resistance and wave-transparent performance.

The invention belongs to the technical field of manufacturing of communication radome materials, and particularly relates to a wave-transmitting material for a millimeter wave radome and a forming method thereof. A polyethersulfone resin material is adopted as a skin layer, a polyether sulfone foam material is adopted as a core layer, and the skin layer and the core layer are both made of the samethermoplastic material which is easy for machine shaping; and the polyethersulfone material has excellent flame retardant properties, and the flame retardant grade of the polyethersulfone material can reach the UL94-V0 grade. When a thermosetting material or a conventional thermoplastic material is used as a wave-transmitting material in the prior art, a flame retardant is added to improve the flame retardant property of the material, but the addition of the flame retardant seriously influences the dielectric properties of the material, so the problem of reduction in wave-transmitting rate ofthe material occurs; and the wave-transmitting material provided by the invention overcomes the above-mentioned problem and can maintain excellent wave-transmitting performance on the premise of meeting flame-retardant requirements.

The invention discloses a method for preparing a double-layer wave-permeable heat proofing and insulating composite structural part. The structural part comprises an inner heat insulation material and an outer heat-proof +material. The method includes steps of preparation of the outer heat-proof material, preparation of silicon oxide hollow microspheres, preparation of chopped fiber reinforced silicon oxide hollow microsphere slurry, casting of the chopped fiber reinforced silicon oxide hollow microsphere slurry and thermal treatment of a structural part blank material. Quartz fiber reinforced quartz composite ceramic serves as the outer heat-proof material, chopped fiber reinforced silicon oxide hollow microsphere ceramic serves as the inner heat insulation material, compact combination of the inner and outer materials is realized by means of slurry casting and high-temperature sintering moulding, and integration of advantageous performances of high temperature resistance, heat proofing, heat insulation, wave permeability and the like is realized.

The invention discloses a glass fiber reinforced plastic antenna housing modified by aluminum hydroxide, which has the advantages of reducing DK value thereof and improving the wave penetrating property of the product. The glass fiber reinforced plastic antenna housing modified by aluminum hydroxide is prepared from the following raw materials in part by weight: 100 parts of unsaturated polyester, 5 to 30 parts of aluminum hydroxide, 0.5 to 2 parts of releasing agent, 0.5 to 2 parts of curing agent and 0.5 to 2 parts of accelerant.

The invention relates to a making method of a high temperature-resistant wave transmitting ceramic coat on a metal surface, and concretely relates to a making method of an amorphous aluminum phosphate-based high temperature-resistant wave transmitting ceramic coat on the metal surface. The purpose of the invention is solving the problems of low high temperature resistance temperature and low wave transmittance of present organic coat systems. The method comprises the following steps: 1, weighing a raw material; 2, preparing an amorphous AlPO4 adhesive solution; 3, preparing a wave transmitting ceramic coating; and 4, preparing the amorphous aluminum phosphate-based high temperature-resistant wave transmitting ceramic coat on the metal surface. The coat obtained in the invention has good dielectric properties, and the dielectric constant is small, so the dielectric loss angle is small, thereby the electromagnetic wave transmittance is improved, and the wave transmittance is greater than 80% in 1-18GHz; and the high temperature resistance is good, the high temperature resistance temperature is 500-1300DEG C, and the amorphous aluminum phosphate-based high temperature-resistant wave transmitting ceramic coat has the advantages of environmentally-friendly and nontoxic raw material, good film forming property, low cost, simple preparation method and short period.

Provided is a microwave antenna wide-frequency flexible antenna cover having the periphery fixed on a fence surrounding the antenna and opposite to the reflection surface of the antenna, the antenna cover is formed by compounding a high-molecular polymer outer layer and a composite fiber textile structure layer mixed with a shielding wave-absorbing filament, a tensioning element used for being connected with a traction mechanism is arranged on one surface, facing the antenna reflection surface, of the antenna cover, the traction mechanism is connected to the inner wall of the fence, and a traction force which enables the antenna cover to change to form a concave surface acts on the antenna cover via the tensioning element. The antenna cover of the structure is good in wave permeability, and the thickness of the antenna cover does not need to be selected according to the working wavelength of the antenna. The antenna cover with a uniform thickness can obtain lower antenna insertion lossin multiple frequency bands, the use of a multi-frequency-band microwave antenna can be met, and the universality of the antenna cover is realized in a relatively wide frequency range, and the defectthat traditional antenna covers made of ABS and other materials have different frequency bands and have poor specificity is overcome.

A microwave sinter material container is formed by a glass container 1 with a cover, a flameproof material 2 and a diamond pot 3, for resolving the problems as non-uniform heating and acute temperature change. The glass container 1 contains the flameproof material 2, the diamond pot 3 is embedded in the material 2, and the thickness of the material 2 is not lower than 2cm, therefore, the invention can quickly heat and save energy, and heat uniformly to prolong the service life of diamond pot.

The invention relates to a frequency selection composite material. The material comprises a composite sheet layer, wherein the composite sheet layer comprises two medium base plates and a structure layer which is arranged between the two medium base plates, the structure layer comprises a plurality of first discontinuous metal wires which are parallel to one another, each of the discontinuous metal wires comprises a plurality of wire segments which are arranged at intervals, the lengths of the first discontinuous metal wires are equal, the widths of the first discontinuous metal wires are equal, and the distances between any two adjacent ends of any two adjacent wire segments are equal; the distances between any first discontinuous metal wires and adjacent first discontinuous metal wires are equal, two corresponding ends of wire segments of corresponding positions of any two adjacent first discontinuous metal wires are flush with each other, the composite material is low in reflection and high in wave transmission rate for low-frequency range electromagnetic waves, so that the material has good wave transmission performance, and at the same time, the material can inhibit high-frequency stage electromagnetic waves and has a band elimination function, so that the material has low-pass high-resistance frequency-selection selection characteristics. The invention also relates to a frequency selection antenna housing and an antenna system made of the frequency selection composite material.

The invention relates to a wideband-elimination metamaterial which comprises a metamaterial slice, the metamaterial slice comprises a media substrate and two structure layers which are attached to two opposite surfaces of the media substrate respectively, each structure layer comprises a plurality of regularly hexagonal metal micro-structures, the two metal micro-structures in the two structure layers, positioned at corresponding positions of the media substrate, form a pair, two adjacent sides of any two adjacent metal micro-structures in each structure layer are parallel to each other, so that the central interval of any two adjacent metal micro-structures is reduced, thus being capable of restraining electromagnetic wave in an ultrawide high frequency range so as to enable the metamaterials to have a wideband-elimination function; and the electromagnetic wave in low frequency range has the advantages of high wave transmittance and small reflection as well as good wave transmitting property. The invention further relates to a wideband-elimination metamaterial antenna housing and an antenna system which are produced by the wideband-elimination metamaterials.

The invention discloses a forming method for an antenna housing based on single layer sandwich foam prefabricated body resin. The forming method comprises the following steps of cutting a foam flat plate to obtain a plurality of flat plate foam units; respectively performing compression molding and peripheral processing on the flat plate foam units to obtain polygon-shaped foam prefabricated bodyunits; paving a first vacuum auxiliary layer, a plurality of layers of fiber cloth, an antenna housing sandwich foam prefabricated body formed by splicing foam prefabricated body units, a plurality oflayers of second fiber cloth and a second vacuum auxiliary layer in a forming mould in sequence; and introducing a resin-based permeable colloidal material between the first vacuum auxiliary layer and the second vacuum auxiliary layer and curing to form an antenna housing blank. The preparation of a foam prefabricated body ensures the configuration of antenna housing sandwich foam with complex curvature molded surfaces; various layers of housing body are cured layer by layer in a curing process, so that the interlayer defects of the housing body are reduced; the state of various layers of thehousing body can also be detected layer by layer; the overall quality of the antenna housing is ensured; the overall strength and rigidity of the antenna housing are improved; and the bearing capacity of the antenna housing is improved.

The invention discloses a wave-transparent multilayer heat insulation structure for realizing thermal control of a spacecraft antenna. The wave-transparent multilayer heat insulation structure comprises reflecting screens (1), spacing layers (2), a surface film (3) and an inner side film (5). The laminated structure of the multiple layers of reflecting screens (1) has the effect of increasing infrared radiation thermal resistance. The spacing layers (2) are arranged between every two layers of reflecting screens (1) to isolate the heat conduction between layers of the reflecting screens (1).The surface film (3) has the effect of reflecting solar spectrum heat radiation. A sewing material (4) is used for multilayer sewing of the reflecting screens (1). An inner side film (5) and the reflecting screens (1) are made of the same material, and the inner side film mainly plays a role in protection to avoid damage caused by friction between the multilayer heat insulation structure and a product . According to the invention, the wave-transparent multilayer heat insulation structure has good transmissivity for working electromagnetic waves of the antenna and has high reliability.

The invention relates to a method for preparing a borosilazane ceramic fiber precursor, which comprises the following steps of: reacting boron trichloride (BC13) with methylamine (CH3NH2) at -80DEG C for 12 to18 hours, reacting at -40 DEG C for 12 to 18 hours to synthesize B(NHCH3)3 micromolecules, and synthesizing Si(NHCH3)4 micromolecules by silicon tetrachloride (SiCl4) and the methylamine (CH3NH2); and removing excessive methylamine from the two type of micromolecules, filtering, mixing, condensing at the temperature of between 135 and 165 DEG C to obtain the precursor with good filament picking effect. The method has the advantages of low cost of raw materials, pure product, and high synthetic yield; and the prepared ceramic fiber precursor is heated to 1,700 DEG C in the ammonia atmosphere, the obtained product has the carbon content of less than 0.05 percent through element analysis, and has good wave permeability and good application prospect.

Provided are a rapidly synthesized polishing-free cordierite ceramic sheet for a microwave oven and a production method of the rapidly synthesized polishing-free cordierite ceramic sheet. The production method comprises the following steps: basic materials including 35-55% of mullite, 15-35% of attaclay, 10-25% of black soil, 0-10% of cordierite, 0-10% of petalite, 0-5% of kaolin, 0-2% of calcium carbonate, 0-2% of potassium feldspar and 0-10% of Al2O3 are prepared according to weight ratio, the additives are polyvinyl alcohol (PVA) and sodium humate, the above all powdery basic materials are subjected to ball-milling to be crushed, the two additives are added into the basic material and are subjected to proper ball-milling to be fully mixed, then the basic materials and the additives are screened through a screen with 200-400 meshes, the iron in the basic materials and the additives is attracted, then the basic materials and the additives are sprayed with mist, dried to make powder, mechanical pressed, applied with glaze, and rapidly sintered at the intermediate temperature of 1220-1300 DEG C to make the product. According to the invention, the raw ores of mullite and attaclay are used to make the sheet, so that the cost of raw materials is greatly lowered, the glaze can be co-fired at one time, and the cordierite crystalline phase is rapidly synthesized by taking advantages of lattice imperfection of various raw mineral materials. The sheet can be pressed very thin and flat so as to avoid polishing.

The invention discloses a basalt fiber prepreg comprising basalt fiber, epoxy resin and release paper, wherein the epoxy resin is soaked into a basalt fiber layer; and the release paper is directly attached to the outer surface of the basalt fiber layer. In addition, the invention discloses a two-step hot melting preparation method of the basalt fiber prepreg, and the preparation method comprises the steps of film preparation and presoaking. The method disclosed by the invention is simple, and the prepared basalt fiber prepreg is favorably applied to the market field of composite materials such as plates, fishing poles and profiled bars. The basalt fiber and a product thereof have abnormally excellent performances on the following aspects of remarkable high temperature resistance and thermal shock resistance, relatively low heat conduction coefficient, high elasticity modulus and tensile strength, good chemical stability, relatively high sound absorption coefficient, favorable electric insulation and dielectric properties, relatively low moisture absorptivity and natural silicate intermiscibility.