173results about How to "Improving Impedance Matching Performance" patented technology

A wireless communication device coupled to a wave antenna that provides greater increased durability and impedance matching. The wave antenna is a conductor that is curved in alternating sections. The wireless communication device is coupled to the wave antenna to provide wireless communication. The wireless communication device and wave antenna may be placed on objects, goods, or other articles of manufacture that are subject to forces such that the wave antenna may be stretched or compressed during the manufacture and / or use of such object, good or article of manufacture. The wave antenna, because of its curved structure, is capable of stretching and compressing more easily than other structures, reducing the wireless communication device's susceptibility to damage or breakage that might render the wireless communication device coupled to the wave antenna unable to properly communicate information wirelessly.

A novel package includes a substrate including an upper surface ground plane connected to a lower surface ground plane by vias through the substrate, a die located on the upper ground plane and including a die pad, a transmission path including, on the upper surface of the substrate, a bonding pad connected to a first transmission line itself connected to a transition pad, and on the lower surface of the substrate, a second transmission line connected to the transition pad by a via through the substrate. A wire bond extends from the bonding pad to the die pad. A portion of the upper surface ground plane and the lower surface ground plane are connected by vias defining opposing walls on either side of the transmission path for signal isolation. A low pass filter for compensating wire bond inductance includes: a first capacitance formed between the bonding pad and at least the lower surface ground plane, the wire bond inductance, and a second capacitance formed between the die pad and at least the upper surface ground plane.

A wireless communication device coupled to a wave antenna that provides greater increased durability and impedance matching. The wave antenna is a conductor that is curved in alternating sections. The wireless communication device is coupled to the wave antenna to provide wireless communication. The wireless communication device and wave antenna may be placed on objects, goods, or other articles of manufacture that are subject to forces such that the wave antenna may be stretched or compressed during the manufacture and / or use of such object, good or article of manufacture. The wave antenna, because of its curved structure, is capable of stretching and compressing more easily than other structures, reducing the wireless communication device's susceptibility to damage or breakage that might render the wireless communication device coupled to the wave antenna unable to properly communicate information wirelessly.

A wireless communication device coupled to a wave antenna that provides greater increased durability and impedance matching. The wave antenna may be in the form of a polygonal, elliptical curve and / or coil shape. The wireless communication device is coupled to the wave antenna to provide wireless communication. The wireless communication device and wave antenna may be placed on objects, goods, or other articles of manufacture that are subject to forces such that the wave antenna may be stretched or compressed during the manufacture and / or use of such object, good or article of manufacture. The wave antenna, because of its curved structure, is capable of stretching and compressing more easily than other structures, reducing the wireless communication device's susceptibility to damage or breakage that might render the wireless communication device coupled to the wave antenna unable to properly communicate information wirelessly.

The invention provides a broadband low-section dual polarization microstrip antenna adopting latticed radiation pastes. The broadband low-section dual polarization microstrip antenna comprises two layers of substrates which are placed up and down; 4*4 latticed radiation pastes placed on the front face of the upper layer of substrate, and the lattices have the same sizes and are periodically arranged; cross coupling grooves engraved on the metal floor on the front face of the lower layer of substrate are respectively symmetrical relative to the x axis and the y axis and are used for activating two orthogonal polarization on the radiation pastes; two Y-shaped microstrip feeder lines vertically to each other and placed on the back surface of the lower layer of substrate are used for activating the above cross coupling grooves, and in order to avoid the intersection of the two microstrip feeder lines, four symmetrical crossover structures are introduced. In the broadband low-section dual polarization microstrip antenna, the 4*4 latticed radiation pastes used by the microstrip antenna can activate the TM10 mode and the inverted TM 20 mode, the two modes can be coupled together by adjusting the sizes of the pastes so as to improve the working bandwidth; and in addition, the sizes of the Y-shaped microstrip feeder lines and the cross coupling grooves are adjusted to improve the impedance matching performance of the antenna, and the bandwidth is further improved.

An antenna module is provided. The antenna module includes a radiator, a feed pin, a ground element, a first parasitic arm, a second parasitic arm and an impedance matching unit. The radiator includes a first section and a second section, wherein an end of the first section is connected to the second section, and the first section is perpendicular to the second section. The feed pin is connected to another end of the first section. The first parasitic arm is parallel to the second section, wherein an end of first parasitic arm is connected to the ground element, and the first parasitic arm couples with the second section of the radiator. The impedance matching unit is connected to the second section and the ground element. The second parasitic arm is partially parallel to the first section, and the second parasitic arm couples with the first section of the radiator, and an end of the second parasitic arm is connected to the ground element.

The invention relates to a fire-retardant type wide-frequency-band high-power compound wave-absorbing material and a preparing method thereof. The material comprises an outer shell, an inner core and a base, wherein the outer shell is a polyhedron formed by a set of pyramids arranged side by side, the wedges of the pyramids are towards the same side, the inner core is located inside the outer shell, the base is located at the bottom of the outer shell, the outer shell is made of non-woven cloths, the inner core and the base are made of polyurethane foams, the inner surface and the outer surface of the outer shell are respectively provided with a first fire-retardant wave-absorbing agent layer in a coating mode, and the inner core and the base are immersed in second fire-retardant wave-absorbing agents. Both the first fire-retardant wave-absorbing agents and the second fire-retardant wave-absorbing agents comprise acetylene black, alpha-SiC, aluminum hydroxide, kaolin, pentaerythritol, and App-3. The corresponding preparing method comprises the steps of preparing the outer shell, preparing the inner core and the base, and inserting the inner core into the outer shell, and therefore the wave-absorbing material is obtained. The wave-absorbing material has good wave absorbing performance and fire retardance, and the preparing method is simple and easy to implement.

The invention provides a radio frequency coaxial electric coupler with a quick-locking device. The quick-locking device comprises a plug quick-locking device and a socket quick-locking device. The back of an elastic jack catch (16) of the plug quick-licking device is fixed on the plug outer conductor (11). The front portion of the elastic jack catch (16) extends with a snap joint (161). A cone face of the snap joint (1611) is arranged on the front lateral surface of the snap joint (161). The cone face of the snap joint (1611) of the elastic jack catch (16) enables the snap joint (161) to contract inward along the radial direction under the effect of the external force. The periphery of the elastic jack catch (16) is provided with a columnar-shaped unlocking sleeve (15). The plug quick-locking device refers to that a block groove (222) is formed on the front end of an outer conductor (22) of the plug along the axial direction. A catching groove (223) is formed radially outward on the wall of the block groove (222). The quick-locking device of the electric coupler has the advantages of being simple in structure, quick in product assembling, and saving the production cost of the quick-locking device.

The invention discloses a multi-spectral broadband anticorrosion stealth coating material. The coating sequentially comprises a camouflage painting coating layer, a graphene anticorrosion coating layer and a radar wave absorbing coating layer from the outside to the inside. The camouflage painting coating layer is a matt polyaspartate polyurea system containing a high-performance pigment, and hasvisible and near-infrared camouflage functions; the graphene anticorrosion coating layer is an epoxy zinc-rich / aluminum-rich system containing graphene, and has anticorrosion and infrared stealth functions; and the radar wave absorbing coating layer is an epoxy resin system containing a wave absorbing material, and has a broadband wave absorbing function. Materials of the camouflage painting coating layer, the graphene anticorrosion coating layer and the radar wave absorbing coating layer are respectively prepared by adding corresponding resins, assistants and pigment fillers at certain proportions according to a certain sequence proportion, and performing high-speed dispersion and grinding. The compatibility among the coating layers is good, and the multi-spectral broadband anticorrosionstealth coating material can be applied to camouflage stealth and corrosion protection in the fields of military vehicles, military devices, power stations, emitting devices and the like.

The invention discloses a ferrite-based ceramic composite material as well as a preparation method and application thereof. The composite material is composed of ferrite, a carbon nanotube and a ceramic material, wherein the ferrite and the ceramic material are cladded on the tube wall of the carbon nanotube, and the ceramic material is one or several kinds of aluminum oxide, aluminum nitride, and silicon nitride. The three phases of materials, namely, the ferrite, the carbon nanotube and the ceramic, are compounded to make the advantages and disadvantages of all phases of materials complementary, so that the electrical conductance of the composite material is increased, the impedance matching performance of the composite material is improved, the wave absorption performance of the composite material is made adjustable, the structure and function integration of the ferrite-based ceramic material is realized, and thus, the application range of the composite material in the high-tech field is expanded. In addition, the powder of the composite material is prepared by adopting a coprecipitation hydrothermal method and is further prepared into a block material by adopting a microwave sintering method, and the ferrite-based ceramic composite material has the advantages that all phases are dispersed uniformly, the densification degree of the sintered material is high, the production cost is low, and the large-scale industrialization is easy to realize.

A wireless communication device coupled to a wave antenna that provides greater increased durability and impedance matching. The wave antenna may be in the form of a polygonal, elliptical curve and / or coil shape. The wireless communication device is coupled to the wave antenna to provide wireless communication. The wireless communication device and wave antenna may be placed on objects, goods, or other articles of manufacture that are subject to forces such that the wave antenna may be stretched or compressed during the manufacture and / or use of such object, good or article of manufacture. The wave antenna, because of its curved structure, is capable of stretching and compressing more easily than other structures, reducing the wireless communication device's susceptibility to damage or breakage that might render the wireless communication device coupled to the wave antenna unable to properly communicate information wirelessly.

The invention discloses a centimeter wave-millimeter wave compatible absorbing composite material. The material has a five-layer structure including a substrate which is an irregular surface made of a random material, a topmost first layer which is composed of a W-shaped hexagonal ferrite absorbent and a acrylic resin adhesive, a second layer which is composed of a carbonyl iron powder absorbent and an epoxy resin adhesive, a third layer which is composed of an Fe85Si1Al6Cr8 nanocrystalline sheet-like absorbent and an epoxy resin adhesive, a fourth layer which is composed of a polycrystallineiron fiber absorbent and an epoxy resin adhesive, and a fifth layer which is composed of a short carbon fiber / carbon black mixed absorbent and a polyurethane adhesive. The material can well solve theproblem of poor centimeter wave-millimeter wave compatible absorbing performance in the prior art, and is a composite wave-absorbing material compatible with electromagnetic waves of centimeter wave-millimeter wave bands.

The invention relates to a nano lead zirconate titanate / cement piezoelectric composite material used in civil engineering sensors and preparation method thereof. The piezoelectric composite material is composed of nano lead zirconate titanate and cement. The preparation method comprises: blending uniformly nano lead zirconate titanate powder and cement powder and water, pressing the mixture in disc shape, then hydrating, drying. The processed material through polarizing and ageing can be used for preparing civil engineering sensors. The piezoelectric composite material of the invention has better connectivity and well piezoelectric response.

A wireless communication device coupled to a wave antenna that provides greater increased durability and impedance matching. The wave antenna is a conductor that is curved in alternating sections. The wireless communication device is coupled to the wave antenna to provide wireless communication. The wireless communication device and wave antenna may be placed on objects, goods, or other articles of manufacture that are subject to forces such that the wave antenna may be stretched or compressed during the manufacture and / or use of such object, good or article of manufacture. The wave antenna, because of its curved structure, is capable of stretching and compressing more easily than other structures, reducing the wireless communication device's susceptibility to damage or breakage that might render the wireless communication device coupled to the wave antenna unable to properly communicate informaton wirelessly.

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 discloses a hierarchical structure hollow CNTs / Co / C fiber wave-absorbing material and a preparation method thereof, and belongs to the technical field of radar wave-absorbing materials.The method takes cotton fibers and Co-containing zeolite imidazole structure metal organic framework ZIF-67 nanoparticles as raw materials. ZIF-67 nanoparticles with a regular dodecahedron microstructure grow and coat the surfaces of the cotton fibers in situ, cotton fibers are carbonized into hollow carbon fibers through a high-temperature carbonization process in a reductive H2 / Ar mixed atmosphere, the pyrolysis of the ZIF-67 metal organic framework nanoparticles and the catalytic growth of the carbon nanotubes are realized so that the hollow CNTs / Co / C fiber wave-absorbing material with themicron carbon fiber-nanotube hierarchical structure is obtained, and under the conditions that the density is 0.02 g / cm<3> and the thickness is 2 mm, the maximum absorption intensity of electromagnetic waves at 14 GHz reaches -59.5 dB, and the effective absorption frequency band width reaches 6.2 GHz (11.8-18 GHz). The technical problems that a traditional wave-absorbing material is high in density, low in absorption strength and narrow in frequency band are solved.

The invention relates to a ferroferric oxide / molybdenum disulfide / carbon fiber composite wave-absorbing material and a two-step reaction preparation method thereof. The preparation method comprises the following steps: firstly, carrying out surface treatment on chopped carbon fibers, mixing the chopped carbon fibers with sodium molybdate and thioacetamide, and carrying out hydrothermal reaction soas to grow a layer of self-assembled molybdenum disulfide nano-sheet on the surfaces of the carbon fibers; and secondly, carrying out hydrothermal reaction so as to modify the surface of a molybdenumdisulfide / carbon fiber composite wave-absorbing material with certain ferroferric oxide magnetic nano-particles, so that the impedance matching of the composite material is further improved, and themicrowave absorption performance of the material is further improved by virtue of high magnetic loss of the magnetic nano-particles. The composite wave-absorbing material is an ideal wave-absorbing material simultaneously having small density, high temperature resistance, high resistance loss (carbon fibers) and dielectric loss (3D nano-molybdenum disulfide) and magnetic loss (ferroferric oxide magnetic nano-particles) and excellent impedance matching performance and oxidation resistance and further has huge practical and application values in the production of composite wave-absorbing materials.

The invention discloses a multilayered structure integrated filter antenna based on a filter Balun, and mainly solves the problem that the volume of the filter antenna of a traditional monolayer micro-strip structure is larger. The multilayered structure integrated filter comprises a dielectric substrate, a filter part and a radiation unit, wherein the dielectric substrate comprises two micro-strip dielectric substrates and a metal ground; the filter part comprises an input port, the filter Balun positioned on the left sides of the dielectric substrates and two output ports connected with thefiler part; the filter Balun comprises two face-to-face C-shaped second-order stepped impedance resonators etched on the upper dielectric substrate and two back-to-back C-shaped second-order stepped impedance resonators etched on the upper surface of the lower dielectric substrate; the radiation unit is etched on the upper surface of the upper dielectric substrate, and comprises two micro-strip lines, two butterfly printing dipoles and a director. The multilayered structure integrated filter antenna has the advantages of compact structure, wide bandwidth, high frequency edge selectivity and good out-of-band rejection, and can be used for the radio frequency front end of a wireless communication system.

The invention relates to a preparation method of high iron slag power doped wave-absorbing foam concrete, wherein the preparation method comprises the step of mixing cement, a physical foaming agent, an addition agent, microfiber, a polycarboxylic acid efficient water reducing agent and water. The preparation method is characterized in that the addition agent is high iron slag power, wherein the high iron slag power and cement are mixed according to the mass ratio of (10-40):(60-90). The adopted material for preparing the foam concrete comprises the high iron slag power which belongs to byproducts in the steel smelting process, wherein the high iron slag power contains a great amount of ferric oxide components, has the properties of magnetism loss and dielectric loss, and can act as a wave-absorbing agent of a cheap building material; and the high iron slag power has wide sources, is low in price, can turn waste into wealth when being used as the building material, and achieves the aim of energy conservation and environment friendliness.

The invention relates to a metal organic framework derived Co / C nanoparticle coated carbonized cotton fiber wave-absorbing material and a preparation method thereof and belongs to the technical fieldof electromagnetic wave-absorbing materials. In the method, cotton, 2-methylimidazole and cobalt nitrate are taken as raw materials, through in-situ growth of a cobalt-containing metal organic framework ZIF-67 on a cotton surface in a methanol solution environment, a cotton fiber precursor uniformly coated by ZIF-67 metal organic framework particles is acquired. And then high-temperature thermal carbonization in a protective atmosphere is performed to prepare the metal organic framework derived Co / C nanoparticle coated carbonized cotton fiber wave-absorbing material, wherein a density is 0.0198 g / cm<3>. A 2-18GHz complex dielectric constant and complex permeability are tested by adopting a transmission line method, a reflection loss curve is calculated, an effective absorption frequency band width is 5.6 GHz (12.0-17.6 GHz) when the reflection loss is lower than-10dB under a thickness of 2mm, and maximum absorption strength at 14.3 GH reaches-45.3 dB. The technical problems that a traditional wave-absorbing material is high in density, low in absorption strength and narrow in frequency band are solved.

The invention provides an ultra-wideband high-gain antenna based on a radial disk impedance converter. According to the ultra-wideband high-gain antenna, the radial disk technology is introduced into the ultra-wideband antenna design for the first time, the design of the radial disk impedance converter is added to a feeding position of the antenna, the ultra-wideband operation problem of different transmission line converters in a feeding system can be solved, and the effect that an antenna radiator can achieve effective conversion and directed radiation of electromagnetic energy under the condition of wideband feeding can be guaranteed. Meanwhile, a ridge waveguide structure with electric field and magnetic field centralizing effects is adopted, and two side surfaces of a ridge waveguide cavity used for energy exchange adopt a triangular ridge structure with an ultra-wideband property, thereby guaranteeing the effect that electromagnetic waves of different frequencies have well matched electromagnetic energy conversion cavities. The ultra-wideband high-gain antenna based on the radial disk impedance converter adopts the large-diameter gradually changing and ridge directional horn radiator design technologies, can achieve high gain and directed radiation of the antenna within ultra-wideband, and can control polarization characteristic and directional diagram sidelobes of the antenna.

First touch patterns of a touch display device are disposed on a first substrate, and have bridge units and first electrode portions. The first electrode portions are disposed spaced from each other. The bridge units are connected with adjacent two of the first electrode portions. A second substrate is disposed opposite to the first substrate. A liquid crystal layer is disposed between the first substrate and the second substrate. One of the bridge units has two first portions, a second portion and two third portions. The first portions are located on the first electrode portions, and directly contact with the first electrode portions. The third portions are located on two of the first portions, and the second portion is located between two of the third portions. The first portion has a first width, and the second portion has a second width smaller than the first width.

The invention discloses a preparation method of a nano composite absorbing material, belonging to the field of electromagnetic. The preparation method comprises the steps of first preparing alkynyl modified magnetic nano particles, and preparing an azide modified graphene oxide substrate by taking graphite as a raw material, then chelating the alkynyl modified magnetic nano particles on the surface of tazide modified graphene oxide in a covalent manner through a cycloaddition reaction, and finally reducing by using hydrazine hydrate, so as to form the nano composite absorbing material; according to the preparation method disclosed by the invention, magnetic nano particles are chelated on the surface of the graphene in the covalent manner through a click coupling method, and the chelated nano particles are not liable to fall off from the surface of the graphene, thus a graphene-ferrite composite material has good conductivity and magnetic property, and has the advantages of high acid resistance, good stability, high practicability and the like; meanwhile, the impedance matching performance of the absorbing material is improved, the material prepared by the invention has better microwave absorbing property on a C waveband and a Ku waveband, and has important application value in the field of electromagnetic shielding.

A novel package includes a substrate including an upper surface ground plane connected to a lower surface ground plane by vias through the substrate, a die located on the upper ground plane and including a die pad, a transmission path including, on the upper surface of the substrate, a bonding pad connected to a first transmission line itself connected to a transition pad, and on the lower surface of the substrate, a second transmission line connected to the transition pad by a via through the substrate. A wire bond extends from the bonding pad to the die pad. A portion of the upper surface ground plane and the lower surface ground plane are connected by vias defining opposing walls on either side of the transmission path for signal isolation. A low pass filter for compensating wire bond inductance includes: a first capacitance formed between the bonding pad and at least the lower surface ground plane, the wire bond inductance, and a second capacitance formed between the die pad and at least the upper surface ground plane.

The invention discloses a transition metal doped magnetic molybdenum disulfide microwave absorbent and a preparation method thereof. The chemical formula of the absorbent is D<x>Mo<1 x>S<2>, wherein Drepresent a transition metal element. The preparation method comprises following steps: mixing a molybdenum source, a sulfur source, transition metal salts, and water; and carrying out hydrothermal reactions of the mixed solution to obtain the absorbent. The transition metal doped magnetic molybdenum disulfide microwave absorbent has the advantages of good impedance matching effect, strong wave absorbing performance, and good uniformity; meets the thin, light, wide, and strong requirements; can be used to shield electromagnetic radiation, can be used an electromagnetic radiation shielding material of mobile phones and household appliances, and has a good application value and application prospect. The preparation method has the advantages of simple technology, easy operation, low production cost, and high yield, can be applied to massive production, and is beneficial for industrial production.

An optical module is provided. The optical module includes a circuit board, wherein the circuit board includes a surface layer, a reference layer, and an intermediate layer positioned between the surface layer and the reference layer. The surface of the surface layer is provided with a first row of golden fingers and a second row of golden fingers, and the first row of golden fingers is closer tothe edge of the circuit board than the second row of golden fingers. At a projection area for by projecting that second row of goldfinger onto the intermediate layer, the intermediate layer is hollowed out to form a hollowed-out area. The hollowed-out area can be formed so that the second row of goldfingers does not flow back through the intermediate layer, but through a reference layer formed therewith, which is conducive to improving the impedance matching effect of the high-speed signal. The hollowed-out area can be formed so that the second row of goldfingers does not flow back through theintermediate layer but through a reference layer formed therewith.

The invention discloses a preparation method of coated flaky carbonyl iron powder. The preparation method comprises the following steps of: (1) preparing an aqueous solution of sodium hydroxide; (2) mixing and ball-milling the aqueous solution of sodium hydroxide, stearate, carbonyl iron powder and absolute ethyl alcohol; (3) cleaning the ball-milled slurry, and carrying out vacuum drying to obtain flaky carbonyl iron powder containing hydroxyl functional groups; (4) mixing the flaky carbonyl iron powder, deionized water and absolute ethyl alcohol, adjusting the pH value of the solution to 6-7with weak acid, and then adding a silane coupling agent and a titanate coupling agent for secondary ball milling; and (5) cleaning the slurry subjected to secondary ball milling, and carrying out vacuum drying to obtain the coated flaky carbonyl iron powder. According to the invention, two ball milling processes are adopted to prepare the flaky carbonyl iron powder which is low in density and good in impedance matching performance and is coated with an organic thin film layer on the surface, the absorption peak value of the carbonyl iron powder is lower than -29.7 dB within the frequency bandrange of 2.2 GHz to 2.9 GHz, the bandwidth of -10 dB reaches 1.72 GHz, and the carbonyl iron powder has the broadband efficient electromagnetic wave absorption characteristic.

The invention relates to the technical field of wireless communication, and provides a liquid-state metal-based antenna and a preparation method therefor, and an antenna radiation symmetrical vibrator. The antenna comprises a control unit, an antenna feeder line, a supporting sleeve, an air pressure balance cavity, a base and two flexible side plates which are prepared from a piezoelectric material with an inverse piezoelectric effect; a ventilating opening is formed in the top of the air pressure balance cavity, and the bottom is connected with the top of the supporting sleeve; openings are formed in the left and right sides of the base respectively, and the two flexible side plates cover the corresponding openings to form a hollow cavity with the base in a jointly surrounding manner; thebottom of the supporting sleeve is connected with the hollow cavity, and the hollow cavity is filled with liquid-state metal; one end of the antenna feeder line is inserted in the bottom of the basewhile the other end is electrically connected with a transceiver; and the control unit is electrically connected with the flexible side plates and used for applying voltages of corresponding values tothe flexible side plates according to a to-be-received frequency signal. The liquid-state metal-based antenna is small in size, convenient to carry, high in radiation gain, electromagnetically compatible, large in frequency band width, and high in impedance matching.

The invention belongs to the technical field of electromagnetic wave absorbing materials, and particularly relates to Co / MnO@C composite electromagnetic wave absorbing material and a preparation method and application thereof. The electromagnetic wave absorbing material is composed of nano-scale manganese oxide, nanoscale cobalt particles and a carbon layer which coats an outer layer, wherein themanganese oxide and the cobalt particles are compounded to form a sheet layer structure, the sheet layer structure forms a monodisperse three-dimensional flower-shaped ball structure, and the carbon layer coats the outer surface of the flower-shaped ball structure. According to the preparation method, the flower-shaped Co / MnO@C composite electromagnetic wave absorbing material is prepared by adopting a synthetic route of a solvent thermal method and high-temperature carbon reduction. The composite powder material has the advantages of being high in saturation magnetization rate, large in coercive force, strong in oxidation resistance, excellent in electromagnetic wave absorption performance, simple in preparation process and low in cost.