247results about How to "Improving Impedance Matching" patented technology

The embodiment of the invention provides a base station antenna, and relates to the technical field of communication. The base station antenna comprises a housing, a phase shifter and a combiner. The shell is provided with combining cavities and phase shifting cavities, the two phase shifting cavities are arranged side by side in the first direction, the combining cavities are arranged on the same side of the two phase shifting cavities in the second direction in a stacked mode, the first direction is perpendicular to the second direction, and the size of the combining cavity in the first direction is larger than the size of any phase shifting cavity and smaller than the sum of the sizes of the two phase shifting cavities; the phase shifter comprises two phase shifting modules corresponding to the phase shifting cavities, each phase shifting module is arranged in the corresponding phase shifting cavity, and each phase shifting module is provided with a phase shifting network; the combiner is arranged in the combining cavity and provided with a combining network, and the combining network is connected with the two phase shift networks. According to the base station antenna provided by the embodiment of the invention, multi-frequency, miniaturization and integration are realized, the gain, radiation efficiency and sidelobe performance of the base station antenna are optimized, the feed network is simple, and the resonance phenomenon is avoided.

The invention discloses a graphene magnetic wave-absorbing material and a preparation method and application thereof.A one-step hydrothermal method is creatively adopted for compounding a magnetic loss type material (CoFe2O4) and a resistance loss type material (RGO) to prepare a novel efficient wave-absorbing performance material, specifically, an iron source and a cobalt source are dispersed into an RGO solution, then sodium acetate and polyethylene glycol are dissolved in the RGO solution, cooling is conducted after heating reaction, and the graphene magnetic wave-absorbing material is obtained. And separating, washing and drying to obtain the product. According to the graphene magnetic wave-absorbing material, the optimal impedance matching and the excellent attenuation characteristic are achieved through the synergistic effect of the two components, and the excellent electromagnetic wave absorbing performance is shown under various thicknesses or even ultra-thin thicknesses. In addition, the material source is wide, the cost is low, the preparation process is green, simple and feasible, the method is suitable for large-scale production, and a theoretical method and a preparation route are provided for application in the aspect of electromagnetic wave absorption in the national defense and civil fields.

The invention is applicable to the technical field of microwave plasmas, and provides a normal-pressure microwave plasma jet device which comprises an outer conductor, an inner conductor coaxially arranged in the outer conductor, a nozzle in threaded connection with the bottom end of the outer conductor, a pin at the end of a radio frequency connector connected with the inner conductor through a connecting conductor, and a gas pipe joint in threaded connection with the outer conductor. The short-circuit plug screw is in threaded connection with the top end of the outer conductor, a short-circuit reflecting surface is arranged at the bottom of a connecting piece installed in the short-circuit plug screw, and the air guide ring is nested on the inner conductor and located between the radio-frequency connector and the air pipe joint; the scheme is simple, reliable and low in cost, stable normal-pressure microwave plasma jet can be obtained without configuring a complex control module to adjust the impedance matching degree of the system, the gas flowing state can be more stable, plasma at an outlet is prevented from being affected, the short-circuit reflecting surface is further designed to be in a threaded up-and-down adjusting mode, and the service life of the system is prolonged. And the impedance matching effect is achieved by finely adjusting the short-circuit reflecting surface.

The invention discloses an ultra-wideband carbon / boron doped high-entropy alloy wave-absorbing material which is prepared by adjusting Fe and Ni elements, adding Si and Al elements and doping a small amount of C or B. The specific component of the wave-absorbing material is (FeaCobSicAldNie) 100-xMx. In addition, the invention also discloses a preparation method of the wave-absorbing material, and the preparation method comprises the following steps: 1, high-entropy alloy smelting; 2, preparing high-entropy alloy spherical powder; 3, carrying out flaky treatment; and 4, stress relief annealing. On the basis of FeCoNi medium-entropy alloy, the content of the Fe element with low cost is increased, the content of the Ni element with high cost is reduced, the Si element and the Al element are added at the same time, then a small amount of non-metal C and B elements are doped to serve as interstitial atoms, lattice distortion is increased, the wave-absorbing performance and corrosion resistance are improved, and the ultra-wideband carbon / boron doped high-entropy alloy wave-absorbing material is obtained.

A tight coupling array antenna based on an integrated microstrip balun is composed of a plurality of polarization units, each polarization unit comprises an antenna floor, a magnetic wave-absorbing material is arranged above the antenna floor, a supporting material is arranged above the magnetic wave-absorbing material, a radio frequency connector is arranged in the antenna floor, the radio frequency connector is connected with one end of a coaxial feeder line, and the other end of the coaxial feeder line is connected with the antenna floor. The other end of the coaxial feeder line sequentially passes through the antenna floor, the magnetic wave-absorbing material and the supporting material; a lower substrate is arranged above the supporting material; a feed balun is printed on the upper surface of the upper-layer substrate, and a multiplexing oscillator arm is printed on the lower surface of the upper-layer substrate; the multi-layer board technology is adopted, the antenna radiator, the coupling body and the feed balun are printed on different copper layers of the multi-layer board respectively, space optimization is achieved, antenna impedance matching is further optimized, and the antenna has the advantages of being excellent in performance and easy to install; according to the invention, the feed balun in the form of the multi-order microstrip transmission line is adopted to optimize all-order microstrip transmission line models, so that the compactness of the antenna unit is effectively improved.

The invention discloses a zigzag structure-based low-pass high-absorption energy selection surface, which comprises a plurality of periodically distributed units, each unit sequentially comprises a frequency selection layer, a dielectric layer and an energy selection layer from top to bottom, the frequency selection layer comprises a first dielectric substrate and a plurality of metal zigzag structures and resistors on the upper surface and the lower surface of the first dielectric substrate, and the metal zigzag structures and the resistors are arranged on the upper surface and the lower surface of the first dielectric substrate. The selectable layer comprises a second dielectric substrate, and a plurality of metal block structures and diodes on the upper surface of the second dielectric substrate; and the frequency selection layer and the selectable layer are separated by the dielectric layer. The energy selection surface and the frequency selection surface are matched in impedance through the dielectric layer, so that when low-power electromagnetic waves are incident, a low-frequency passband with low insertion loss is realized, and a relatively wide absorption frequency band is formed outside the passband; and when high-power electromagnetic waves are incident, a reflection frequency band with relatively high shielding effectiveness is realized in a working frequency band, and a relatively wide absorption frequency band is formed outside the band. The device is simple and clear in overall design structure principle and has a wide application prospect.

The embodiment of the invention provides an indoor embellished antenna, and belongs to the technical field of communication antennae, the indoor embellished antenna comprises a dielectric substrate, and one side of the dielectric substrate is provided with a ground layer substrate; the patch substrate is arranged on the side, away from the stratum substrate, of the dielectric substrate, and hole sets arranged in an array mode are formed in the circumferential edge of the patch substrate and penetrate through the dielectric substrate and the stratum substrate. The main open groove is formed in the patch substrate, the main open groove is formed in an annular closed mode, any two opposite sides of the main open groove are respectively provided with a guide groove, the guide grooves extend to the open hole set, and the guide grooves, the main open groove and the open hole set jointly divide the patch substrate into two resonance areas; wherein the main slot forms a central patch resonant cavity, and each resonant region forms a substrate integrated waveguide resonant cavity. According to the indoor embellished antenna provided by the invention, the central patch resonant cavity and the substrate integrated waveguide resonant cavity are integrated in one frequency band, so that multi-resonance-point operation can be realized under the low-profile size design.

The invention provides a four-frequency-band reconfigurable load modulation balanced amplifier structure and a regulation and control method thereof, and aims to solve the problems that in the existing power amplifier technology, the efficiency is low during power back-off, and multi-scene requirements cannot be met. The four-frequency-band reconfigurable load modulation balanced amplifier comprises a 90-degree Lange coupler of an input port and a 90-degree Lange coupler of an output port; a two-stage reconfigurable balanced power amplifier composed of an input matching network, a reconfigurable inter-stage matching network and an output-stage pre-matching network and a two-stage control signal power amplifier are combined through an active load modulation technology and a reconfigurable technology, a compact matching network is utilized, and a reconfigurable power amplifier is formed. The efficiency of output power rollback is greatly improved, and the system requirements in different frequency band application scenes can be met.

The invention provides a preparation method of a carbon / magnetic metal / aramid nanofiber composite aerogel wave-absorbing material, and belongs to the field of wave-absorbing material preparation, and the preparation method comprises the following steps: (1) respectively preparing a polyvinyl alcohol solution, an aramid nanofiber solution, a polyphenol solution and a magnetic metal salt solution; (2) sequentially adding the aramid nanofiber solution, the polyphenol solution and the magnetic metal salt solution into the polyvinyl alcohol solution, and stirring at room temperature to uniformly disperse the mixed solution; and (3) pouring the uniformly dispersed solution into a mold for freezing and freeze-drying. And (4) finally, carbonizing the dried sample in an inert atmosphere to obtain the carbon / magnetic metal / aramid nanofiber composite aerogel. The method is easy to operate and environmentally friendly, and the prepared carbon / magnetic metal / aramid nanofiber composite aerogel has excellent wave absorbing performance and mechanical performance.

The invention provides an intrinsic magnetic MXene material and a preparation method and application thereof, the preparation method comprises the following steps: S1, mixing an aqueous solution of MXene with an alkaline reagent, and carrying out ultrasonic dispersion to obtain a mixed dispersion liquid; freezing the mixed dispersion liquid into a solid by liquid nitrogen; the alkaline reagent is potassium hydroxide or sodium hydroxide; s2, the obtained solid is subjected to freeze drying, and the Archimedes screw type MXene aerogel is obtained; s3, the Archimedes spiral type MXene aerogel is subjected to heat treatment under the protection of inert gas, and the intrinsic magnetic MXene material is obtained. The invention designs and develops a single-component pure MXene electromagnetic wave absorbing material on the premise of not introducing magnetic nanoparticles.

The invention relates to a preparation method of a lightweight reduced graphene oxide-silicon dioxide electromagnetic wave absorbing material. The invention belongs to the technical field of electromagnetic wave absorbing materials. The invention solves the problems that the impedance of the existing reduced graphene oxide is mismatched, the density of the modified reduced graphene oxide composite wave-absorbing material is increased and the preparation method is complicated. The method comprises the following steps: performing chemical crosslinking on graphene oxide, silicon dioxide and a silane coupling agent to obtain a precursor; and drying and sintering the precursor. The material prepared in the invention has good impedance matching and abundant interface polarization and relaxation effects, can effectively reduce the reflection loss value of electromagnetic waves and increase the effective absorption bandwidth of the electromagnetic waves, and has excellent electromagnetic wave absorption performance. When the thickness of the material is only 1.5 mm, the RL of the material can reach-54.08 dB, and when the thickness of the material is 1.7 mm, the effective absorption bandwidth of the material can reach 5.12 GHz. In addition, the density of the material is only 0.083 g / cm < 3 >, the process is simple, and stable batch production can be realized.

The invention relates to a semi-active pressure-resistant low-frequency sound absorption covering layer containing a piezoelectric composite material. The semi-active pressure-resistant low-frequency sound-absorbing covering layer containing the piezoelectric composite material structurally comprises a surface protecting layer which is arranged on the outermost side of the covering layer and converts sound energy into heat energy through a damping effect; the piezoelectric composite material layer is arranged on the inner side of the surface protection layer, converts sound energy into electric energy through a direct piezoelectric effect, and dissipates the electric energy through a shunt branch; the cavity layer is arranged on the inner side of the piezoelectric composite material layer and absorbs sound through a cavity resonance effect, waveform conversion and a damping effect; the substrate layer is arranged on the inner side of the cavity layer to seal the cavity layer so as to absorb sound with a damping effect; wherein the composite material layer is electrically connected with an external shunt branch, and the shunt branch is formed by connecting a negative capacitance element, a resistance element and an inductance element in series.

The invention provides a characteristic impedance testing method, device and equipment and a medium, and relates to the technical field of radio frequency, the characteristic impedance testing method is used for testing to obtain a characteristic impedance value of a cable, the cable is provided with an input end and an output end, and the input end of the cable is used for accessing a radio frequency signal. The characteristic impedance test method comprises the steps of controlling an input end of a cable to access a radio frequency signal, controlling an output end of the cable to be grounded, obtaining a first voltage value and a first current value of the output end of the cable, and obtaining a first impedance value according to the first voltage value and the first current value; controlling the input end of the cable to access a radio frequency signal, controlling the output end of the cable to open, obtaining a second voltage value and a second current value of the output end of the cable, and obtaining a second impedance value according to the second voltage value and the second current value; and determining a characteristic impedance value of the cable according to the first impedance modulus value and the second impedance modulus value. According to the invention, the characteristic impedance value of the cable can be tested.

The invention discloses a multi-component alloy / carbon black composite wave-absorbing material. The molecular formula of the composite wave-absorbing material is (Fe50Co20SiaAlbNic)-xC, the invention also discloses a preparation method of the composite wave-absorbing material. The preparation method comprises the following steps: step 1, preparing the multi-component alloy spherical powder; 2, ball milling and powder mixing; step 3, spray granulation; step 4, carrying out primary flaking; step 5, dry grinding; and step 6, carrying out second-time flaking. The composite wave-absorbing material is obtained by compounding the multi-component alloy mainly containing magnetic loss and the carbon material mainly containing conductive loss, so that the problems that the reflection loss is low and the absorption frequency band is narrow when the multi-component alloy is singly used and the effective absorption frequency band is narrow and the oxidation resistance is poor when the carbon black is singly used can be solved; the combination of the two can improve the impedance matching of the material, and is suitable for the technical field of electromagnetic shielding wave-absorbing materials.

The utility model relates to the technical field of refrigeration and storage, in particular to a silencer and a refrigerating and freezing device. The silencing device comprises a silencing body, heat dissipation through holes horizontally penetrating through the two opposite side walls are formed in the silencing body, and sound absorption holes are formed in the hole walls of the heat dissipation through holes. Noise elimination cavities which are formed around the heat dissipation through holes and communicate with the sound absorption holes are further formed in the noise elimination body, at least one noise elimination cavity is provided with a bent position, and the bent position is of a first arc-shaped structure. When airflow enters the silencing cavity, the risk that the airflow generates secondary noise at the bending position of the silencing cavity can be reduced. According to the utility model, the impedance matching problem can be essentially improved, so that the silencer not only has a wide negative refractive index frequency band, but also can be well matched with air impedance. According to the refrigerator, the problem that in the prior art, a silencer is poor in noise reduction effect on the compressor bin is solved, the sound quality of the refrigerator is improved, and therefore the purpose of improving user experience is achieved.

The invention discloses a low-pass high-absorption energy selection surface based on a magnetic material, which comprises a plurality of periodically distributed units, and each unit comprises a magnetic material layer and an energy selection layer which are tightly attached from top to bottom; wherein the selectable layer comprises a dielectric substrate, and first to seventh metal structures and first to eighth diodes which are arranged on the dielectric substrate. A complete loop is formed through a plurality of diodes, and through impedance matching between a magnetic material and an optional layer, when low-power electromagnetic waves are incident, a low-frequency passband with low insertion loss is realized, and an ultra-wide absorption band is realized at a high-frequency position; when high-power electromagnetic waves are incident, high shielding effectiveness is achieved in a working frequency band, and an ultra-wide absorption band is achieved outside the band. The device is simple in overall design structure, clear in principle, convenient to machine, low in cost and very wide in application prospect.

The utility model relates to the field of microwave heating, in particular to a microwave assembly for heating. The microwave assembly comprises a microwave generator, a waveguide power division network and a shell, a heating cavity is formed in the shell; at least one side of the heating cavity is provided with a microwave assembly, and the microwave assembly comprises a plurality of antenna units and a rotating assembly; the antenna units are distributed in an array; the microwave generator is connected with the antenna unit through a waveguide power division network; the rotating assembly is connected with the antenna units, and the antenna units rotate in the array distribution to form a phased array. The stirring of microwave energy is realized through the rotation of the antenna unit, so that microwaves radiated into the heating cavity through the antenna change continuously, and the purpose of uniform heating is achieved. Through the combination of the dynamic antenna and the static heated object, the utilization of the heated object to the heating cavity almost reaches the maximum size of the diagonal line in the heating cavity, and the space occupation of a rotating disc required by the rotation of the rotating disc type heated object to the heating cavity is also eliminated.

The invention relates to a rare earth composite magnetic material, a rare earth composite magnetic wave-absorbing material and a preparation method thereof. The rare earth composite magnetic material comprises rare earth permanent magnet alloy particles and magnetic metal micro powder which are compounded together, and the surfaces of the rare earth permanent magnet alloy particles are modified with oleic acid. The rare earth composite magnetic wave-absorbing material is obtained by arranging rare earth composite magnetic materials in multiple layers according to an impedance matching principle. According to the method, rare earth permanent magnet alloy blocks are converted into rare earth permanent magnet alloy particles by introducing a ball milling process, electromagnetic parameters of the rare earth permanent magnet alloy particles are optimized, and the rare earth permanent magnet alloy particles are further compounded with magnetic metal micro powder, so that a heterogeneous interface is formed between a rare earth compound and the metal micro powder; impedance matching of the rare earth composite magnetic material is optimized by regulating and controlling the dielectric constant of the rare earth composite magnetic material, electromagnetic parameter regulation and control of the composite wave-absorbing material and effective improvement of the wave-absorbing performance are achieved, and finally the rare earth composite magnetic wave-absorbing material with the broadband absorption characteristic is prepared by optimizing different interlayer matching thicknesses and concentrations.

The present invention discloses a core-shell Ni / Co alloy @ nitrogen-doped carbon-based absorbing composite material and a preparation method thereof. First, a Ni / Co-MOF precursor is prepared by a simple hydrothermal reaction, and then a core-shell Ni / Co@C composite absorbing material is obtained by high-temperature treatment under an argon inert environment. The composite absorbing material has an optimal effective absorbing bandwidth (RL) value of 8.9 GHz at a thickness of 3.5 mm, and can reach 71.9 dB at a frequency of 8.9 GHz. The effective absorbing bandwidth of RL<10 is as high as 16 GHz, covering the S, C, X and Ku bands, and due to the formation of a carbon-wrapped nickel-cobalt core-shell structure, the material has good stability. The absorbing material prepared by the method of the present invention is environmentally friendly, has good stability, has a wide absorbing bandwidth, has high reflection loss, is simple in process, and is suitable for large-scale production.

The invention relates to the technical field of wireless communication, and discloses a low orbit satellite communication K / Ka frequency band broadband dual circularly polarized antenna. According to the technical scheme, the antenna is characterized by comprising a radiation port surface, a resonant cavity, a dual-circular polarizer, a quasi-TEM transmission air cavity layer, a left polarization broadband feed network layer, a right polarization broadband feed network layer, a TEM mode conversion terminal, a polarization switch, a transceiving duplexer, a first standard waveguide port layer and a second standard waveguide port layer. The antenna is simple in structure, has a self-packaging characteristic, is good in electromagnetic compatibility, and can achieve the high gain, wide bandwidth and high circular polarization purity of the antenna. The shielding air cavity is formed by structure stacking and the metalized through holes, and when a plurality of circuits are integrated together, mutual interference is small, the structure is compact, assembling is convenient, and electrical performance is excellent.

An ultra-wideband end-fire antenna with a common aperture embedded in a metal carrier includes a metal cavity with a coaxial cable compartment on one side. A radiator module is connected to the bottom of the metal cavity via a radiator fixing slot. The radiator module includes a common aperture antenna substrate. A low-frequency radiator is printed on the side of the common aperture antenna substrate closer to the coaxial cable compartment, and a high-frequency radiator is printed on the side farther from the coaxial cable compartment. This invention utilizes a dual-band antenna in a common aperture design to enhance the channel capacity and anti-fading capability of the communication system. At the same time, by achieving the antenna's carrier conformal characteristics, high isolation, and miniaturization, it enriches the antenna's application scenarios and improves the overall performance of the communication system.

The invention discloses a method and equipment for improving matching of a measured piece in an attenuation measurement system, belongs to the field of radio metering, and comprises the method for improving matching of the measured piece in the attenuation measurement system, and the core of the method is that a precise matching absorption load is added in a front-end transmission system of the measured piece; energy transmission is realized on a waveguide wide side of the precise matching absorption load through a coupling hole; a transmission waveguide is additionally arranged above the coupling hole, and energy is transmitted to a measured piece in the forward direction; and a precise matching absorption load is added in the reverse direction to absorb energy in the reverse direction, so that the measured piece matching improvement equipment in the attenuation measurement system is formed, and finally the measured piece matching of the attenuation measurement system is improved. According to the method and the equipment, the impedance matching of the measured piece is improved by using the precise matching load, the voltage standing-wave ratio of the load level is realized, and the attenuation measurement accuracy is improved. The tested piece matching improvement equipment developed by using the method is directly connected to two ends of the tested piece in an attenuation measurement system, so that the impedance matching of the tested piece is improved.

The utility model provides an antenna and an automobile, and relates to the technical field of automobile accessories. The antenna comprises a base which is used for being arranged on an automobile; the shell is detachably connected to the base; the antenna module is used for receiving radio signals, the antenna module is arranged on the base, and the antenna module is located in the shell; the antenna module is electrically connected with the power supply adaptation module, the power supply adaptation module is detachably connected to the base, the power supply adaptation module is located in the shell, and the power supply adaptation module is used for simultaneously adapting the antenna module to at least two power supplies with different voltages. According to the antenna and the automobile, the applicability of the antenna is improved.

This invention discloses a coatable, moldable dual-functional coating material for heat protection and stealth, and its preparation method. The coating material is formed from a SiC-based composite ceramic aerogel slurry, a perovskite / MAX phase composite ceramic absorber, and a high-temperature resistant binder. The composite ceramic aerogel slurry is composed of SiC micro / nano-scale aerogel powder, SiC nanowires, and a high-temperature resistant binder; the perovskite ceramic absorber is lanthanum strontium manganese oxide (La). 1‑x Sr x MnO3), lanthanum strontium iron oxide (La) 1‑ x Sr x FeO3), lanthanum strontium cobalt oxide (La) 1‑x Sr x The MAX phase ceramic absorber is Ti3SiC2, and it contains substances such as CoO3. The technology of this invention enables the rapid application of coating materials to the surface of equipment via brushing, enhancing high-temperature radar absorption stealth and thermal protection capabilities, and facilitating the preparation and efficient repair of high-temperature stealth coatings.

The invention relates to the technical field of antennas, and discloses a double-blade radiation patch which is in a flat shape with a narrow middle part and two wide ends. The invention further discloses a fractal feed double-leaf antenna, a reflecting plate, a first micro-strip plate, a fractal feed structure, a second micro-strip plate, a coupling structure with a coupling gap, a third micro-strip plate and the double-leaf radiation patch are sequentially arranged from one end of the antenna to the other end of the antenna, and in the direction perpendicular to the reflecting plate, the fractal feed structure is arranged on the first micro-strip plate, and the fractal feed structure is arranged on the second micro-strip plate. The fractal feed structure and the coupling slot are arranged in a coupling manner, and the double-leaf radiation patch is correspondingly arranged right above the coupling slot. The antenna adopts a fractal structure for feeding, a single feed point introduces a double-branch structure and is respectively coupled to two slots, and meanwhile, a secondary matching branch is introduced, so that the current distribution is effectively improved, and the impedance matching is further improved. The unit spacing in the form can be one time of wavelength of high frequency, and a large-spacing antenna under the condition of a single feed point is successfully realized.

The application belongs to the technical field of antenna in the communication system comprehensive design, and particularly relates to a kind of omnidirectional broadband antenna based on multimode resonance, L-shaped folded dipole, rectangular loop, U-shaped branch and SMA joint are located at the lower surface of dielectric substrate, feed line is located at the upper surface of dielectric substrate, first metallized via hole and second metallized via hole in the up-down direction are opened on dielectric substrate, the outer conductor of SMA joint is connected with the right arm of L-shaped folded dipole, the inner conductor of SMA joint is connected with one end of feed line by passing through the right arm of L-shaped folded dipole and first metallized via hole, the other end of feed line is connected with the left arm of L-shaped folded dipole by passing through second metallized via hole, the application generates new resonance frequency by bending traditional dipole to form L-shaped folded dipole;rectangular loop is added around L-shaped folded dipole, two new resonance modes are introduced, and the bandwidth of antenna is further widened.

The invention relates to the technical field of manganese zinc ferrite and discloses a method for preparing a manganese zinc ferrite material. A composite material containing both a "conductive" element and a "magnetic" element is prepared by a physical mixing method. The manganese zinc ferrite has a large resistivity, and electromagnetic waves can easily enter the interior of the material to achieve electromagnetic impedance matching, so that the magnetic loss performance is outstanding; the polythiophene Schiff base conductive polymer can coordinate with metal ions to form a metal complex, thereby increasing the dielectric loss of the composite material and reducing the reflection of electromagnetic waves on the incident interface; the Schiff base structure transfers charges through the conjugation of single and double bonds, and the double bond electron rotation makes it magnetic, and the pinning effect of rare earth lanthanum increases the loss caused by domain wall resonance, thereby effectively improving the magnetic properties and wave absorption performance of the composite material, so that the prepared manganese zinc ferrite material has excellent properties of broadband and high conductivity.

The application relates to the technical field of electromagnetic wave absorbing materials, in particular to an electromagnetic wave absorbing material and a preparation method thereof. The electromagnetic wave absorbing material comprises an inverse perovskite type palladium iron nitrogen compound, the inverse perovskite type palladium iron nitrogen compound is one or more of PdNFe3, PdN(Fe 1‑x M x )3 and (Pd 1‑y L y )NFe3, wherein M is selected from one or more of Co, Ga and Sn, L is selected from one or more of Zn, Ni and Cu, 0 < x < 1 and 0 < y < 1. The electromagnetic wave absorbing material has strong electromagnetic wave attenuation capacity, a wide effective absorption bandwidth and good impedance matching performance, and is simple to prepare and has good application prospect.

The invention provides a magnetron structure. The magnetron structure comprises a main body part which is provided with an accommodating cavity; the main body part is provided with a plurality of fan blade parts, and the multiple fan blade parts are arranged around the containing cavity at intervals; a resonant cavity is formed in a gap between every two adjacent fan blade parts; the resonant cavity is communicated with the accommodating cavity; the mounting groove is formed in the multiple fan blade parts and communicates with the resonant cavity, so that an annular groove is defined; the diaphragm belt is arranged in the mounting groove; wherein the mounting groove comprises a shallow groove section and a deep groove section, and the depth of the deep groove section is larger than that of the shallow groove section in the extending direction of the containing cavity; at least two shallow groove sections and at least two deep groove sections are arranged, and the shallow groove sections and the deep groove sections are alternately arranged at intervals. Through the technical scheme provided by the invention, the technical problem that the supporting stability of the structure for supporting the diaphragm belt in the magnetron in the prior art is relatively poor can be solved.

The utility model discloses a coupler which comprises a coaxial line and a multilayer circuit board arranged on the coaxial line, and the coaxial line comprises an inner conductor and an outer conductor. The multilayer circuit board comprises a dielectric substrate, a first ground layer, a first microstrip line, a second ground layer, a third ground layer, a second microstrip line, a third microstrip line and a first via hole, wherein the first ground layer and the first microstrip line are arranged on one side surface of the dielectric substrate; the second ground layer is arranged in the dielectric substrate; the third ground layer, the second microstrip line and the third microstrip line are arranged on the other side surface of the dielectric substrate; and second and third vias through the second formation. The first ground layer is connected with the outer conductor, the first microstrip line is located in a through hole of the first ground layer, the line width of one end of the first microstrip line is smaller than 50 ohm, the line width of the other end of the first microstrip line is larger than 50 ohm, and the first microstrip line is coupled with the inner conductor through the slot of the outer conductor; the second microstrip line and the third microstrip line are located in the two gaps of the third ground layer; the second and third microstrip lines are connected with two ends of the first microstrip line through the second and third via holes.