385results about How to "Achieve Impedance Matching" patented technology

The invention provides a test system and a test method. The testing system comprises a test fixture, a test device and a differential tunable matching network, wherein the test fixture is provided with a bearing structure for loading a chip to be tested and a test port electrically connected to the chip to be tested; the test device comprises a radio frequency signal source, a receiving unit and a processing and display unit; the radio frequency signal source is provided with at least one radio frequency test port; the receiving unit is used for at least receiving a reflected signal and a transmitted signal which are generated after a radio frequency signal passes through the chip to be tested; the processing and display unit is used for processing the received radio frequency signal and displaying the processed signal; and the differential tunable matching network is provided with an input port and a differential output port and is used for tuning the impedance of a load end including the chip to be tested to make the impedance of the load end matched with the internal resistance of the test device and providing the test device to measure the characteristic of the chip to be detected in the test fixture. Compared with the prior art, the invention has the advantages that: the differential tunable matching network is provided for realizing impedance matching, the test system and the test method are easy and convenient to operate, and a more accurate test result can be acquired.

The invention discloses a high-different frequency isolation broadband double-frequency base station antenna array, which comprises at least one high-frequency antenna unit, a low-frequency antenna unit and a floor board, wherein when one high-frequency antenna unit exists, the high-frequency antenna unit is placed at one side of the floor board, when multiple high-frequency antenna units exist, the high-frequency antenna units are placed at two sides of the floor board respectively, each high-frequency antenna unit comprises multiple oscillator arms and a Balun, the oscillator arms are connected through a distributed inductor, and feeding is carried out through the Balun; the low-frequency antenna unit is placed in the middle of the floor board and comprises multiple oscillator arms and a Balun, the oscillator arms are connected through a distributed capacitor, feeding is carried out through the Balun, the Balun is provided with a feeder line and an H-type microstrip branch, and the H-type microstrip branch is connected with the feeder line. In a condition of not cascading filters, high isolation in a condition in which the distance between the different-frequency antenna units is small and the floor board is small can be realized, insertion loss of a filter is avoided, a stable pattern in a broadband is realized, and due to a decoupling structure, the volume of an antenna unit is not added extraly.

The invention discloses a dual polarization base station antenna with Y-shaped feed units. The dual polarization base station antenna with the Y-shaped feed units comprises a dielectric substrate, a metallic reflection plate, a first coaxial line and a second coaxial line. The two sides of the metallic reflection plate are provided with metal flanges. The lower surface of the dielectric substrate is provided with a first annular radiating element, a second annular radiating element, a third annular radiating element and a fourth annular radiating element, wherein the first annular radiating element and the second annular radiating element are in mutual symmetry to form a first antenna structure, and the third annular radiating element and the fourth annular radiating element are in mutual symmetry to form a second antenna structure. The upper surface of the dielectric substrate is provided with the first Y-shaped feed unit and the second Y-shaped feed unit. The first coaxial line is connected with the second annular radiating element and the first Y-shaped feed unit. The second coaxial line is connected with the fourth annular radiating element and the second Y-shaped feed unit. The dual polarization base station antenna is good in performance, simple in structure, easy to process, low in processing cost and convenient to adjust.

The invention discloses a C / X dual-band microstrip antenna, and belongs to the technical field of antennas. The antenna adopts a dual-layer high-resistance silicon medium structure in which two frequency bands share a rectangular radiation patch; an upper layer of high-resistance silicon media bears a rectangular patch and an X frequency band feed line; an air cavity is etched on an upper layer of high-resistance silicon to reduce a composite dielectric constant of the high-resistance silicon; a lower layer of high-resistance media bear a C frequency band feed line; an X frequency band adopts microstrip coplanar feeding; and a C frequency band adopts slot coupling feeding. The C / X dual-band microstrip antenna or a C / X dual-band two-element microstrip antenna has the following advantages of: 1, singlechip and dual modes, simple structure and flexible design; 2, multiple frequencies; 3, miniaturization and light weight; and 4, integration. The C / X dual-band microstrip antenna can be widely applied to airborne point-to-point communication tools, such as satellite communications, control, guide and radars.

This invention relates to a broadband single ridge waveguide slot array, resolving that the size, weight, loss, scanning angle and other aspects of existing waveguide slot array can not meet the special requirements. Its features are: the radiation waveguide has symmetric metal-single ridge on the center line of hemline and rectangular cross section, which connects with the feeding waveguide just below the bottom. The feeding waveguide has symmetric metal-single ridge on the hemline centerline. Coupling gap is set between radiation and feeding waveguide horizontally. The invention uses a single-ridge radiation waveguide to reduce the width of antenna, divides array into a number of sub-ones and feeds by power divider to improve the working bandwidth, uses ridge waveguide antenna to improve efficiency and reduce processing difficulties, uses coaxial connectors to easily realize impedance matching.

The invention discloses a high-linearity broadband stacking low noise amplifier based on a gain compensation technology. The high-linearity broadband stacking low noise amplifier comprises a two-stacking low noise amplification network, an interstage matching network and a two-stacking gain expansion amplification network which are connected in sequence; and a first power supply bias network and a second power supply bias network which are connected with the two-stacking low noise amplification network and the two-stacking gain expansion amplification network. According to the high-linearity broadband stacking low noise amplifier, a serial stacking structure is realized through adoption of two transistors with different sizes and ultra wide band noise and impedance matching are realized through combination of an RLC feedback network; through utilization of the gain compression compensation technology, the gain compression property of the two-stacking low noise amplification network is cancelled within a certain bias range through the two-stacking gain expansion amplification network and a linearity index of the amplifier is improved, so the whole low noise amplifier has good broadband, linearity, low power consumption and low noise amplification capability; and moreover, the low breakdown voltage property of an integrated circuit technology is avoided and the stability and reliability of a circuit are improved.

The invention discloses a small ultrawide band antenna with a trapped wave characteristic. The small ultrawide band antenna consists of a dielectric substrate (1) and metal coating layers positioned on the upper surface and the lower surface of the dielectric substrate (1), wherein a radiation unit (2), a microstrip feeder (4) and interdigital capacitance loading resonance rings (6) and (7) are arranged on the upper surface of the dielectric substrate; the microstrip feeder (4) consists of a microstrip line with characteristic impedance of 50 ohms and a microstrip line with characteristic impedance which is gradually changed linearly from 50 ohms; the two interdigital capacitance loading resonance rings (6) and (7) with different sizes are printed on two sides of the microstrip feeder and used for forming a trapped wave frequency band; and a metal floor consists of a rectangle (3) and a reversed L shape (5) and is printed on the lower surface of the dielectric substrate (1). The working frequency band of the antenna covers 3.1 to 10.6 GHz; interference signals of a plurality of narrowstrip frequency bands can be filtered as required by adjusting relevant parameters, and available frequency bands are retained; and the antenna has the advantages of wide frequency band, narrow attenuation band, miniaturization and strong anti-interference capacity.

This invention relates to a wireless receiving type, microelectron mechanical, and microwave power level sensor and its preparation method. The invention uses coplane radiating guide (1) to take over microwave power to create resistance heating, through thermocouple to measure microwave signal amplitude. This sensor forms coplane radiating guide on gaas substrate (8). coplane radiating guide then connect with coplane waveguide transmission line(4) to transmit microwave signal. The terminal of coplane waveguide transmission line(4) has two parallel resistance as microwave load resistance(5). Load resistance through heating creates its right side thermopile (7) to heat. Thermopile (7) owing to exothermic disproportionation cause cold and hot point, form temperature variation. This temperature difference owing to seebeck effect creates constant voltage at two output port of thermopile and ouput by two pressure welding piece (6). The ratio between this output thermo voltage and input microwave efficiency is direct ratio, so measuring this volatge could obtain numerical value of microwave power.

The invention discloses a China Mobile 4G full band absorbing material, and a preparation method and application thereof. A composite auxiliary agent of a silane coupling agent and a stearate surfactant is added to a carbonyl iron powder, and a high-energy ball milling process is carried out to prepare a sheet-shape carbonyl iron powder absorbing material with excellent impedance matching performance. The material can meet the following requirements: in the frequency range from 1 to 18 GHz, an absorbing coating has thickness of less than or equal to 2mm; the absorbing material has -8dB absorption bandwidth reaching 1.5GHz (1.3-2.8GHz), which completely covers the whole band of China Mobile 4G (1.8GHz-2.8GHz); the proportion of the silane coupling agent and stearate can be adjusted to obtain proper sheet structure and size, thus changing the relationship between the complex permittivity and complex permeability to reach impedance matching, and then adjusting the absorption peak position. The material achieves the purpose of selecting absorption interference noise at three arbitrary main frequencies of China Mobile 4G and improving the signal-to-noise ratio of the base station and mobile terminal.

The invention relates to the technical field of microwave absorbing materials and provides a composite microwave absorbing agent and a preparation method thereof. The composite microwave absorbing agent is in a porous structure, and carbon-containing Co / CoO nano frameworks are sequentially stringed on carbon nano fibers. The preparation method of the composite microwave absorbing agent includes: acidizing the carbon nano fibers, allowing adsorption of Co<2+> on surfaces of the acidized carbon nano fibers, coordinating with 2-methylimidazole, and pyrolyzing and carbonizing to obtain the composite microwave absorbing agent. Problems of unfavorable absorption performances and high pyrolysis temperature and energy consumption in a preparation process of composite microwave absorbing agents inthe prior art are solved. The prepared composite microwave absorbing agent in the porous framework structure has advantages of light weight, excellent absorption performances, technical simplicity andlow production cost.

The invention provides a waveguide direct-feed-type microwave plasma torch device which comprises a waveguide portion, a tuning and auxiliary portion and a coaxial torch tube portion. The waveguide portion comprises a gradual-changing-type waveguide and a narrow-edge compression waveguide. The coaxial torch tube portion comprises an outer tube, a middle tube, an inner tube, a regulating stud and a coaxial centering washer. The tuning and auxiliary portion comprises a waveguide short-circuit sliding end, a torch tube reflection tuning end and a torch tube upper portion regulating end. The waveguide short-circuit sliding end comprises a waveguide short-circuit plate and a sliding rod. The torch tube reflection tuning end comprises the regulating stud and a reflection plate. The gradual-changing-type waveguide and the narrow-edge compression waveguide are directly fed into the metal coaxial torch tube, a formed plasma has a central channel so that a sample can be conveniently led into the plasma, and meanwhile bearing capacity for the sample is intensified. The device eliminates a coaxial cable, a coupling ring and the like, improves coupling efficiency, and expands the use power of the torch tube. The device can be used as an ionization source of an atomizer and an ionization source of an atom mass spectrum or used for decomposition and treatment of harmful chemicals and rubbish.

The invention discloses an electric vehicle advancing type wireless charging device and control method of the electric vehicle advancing type wireless charging device. The device comprises a rectifier, several magnetic coupling resonate emitting electrode groups, and a vehicle-mounted resonate receiving electrode, wherein every magnetic coupling resonate emitting electrode group comprises a first resonate emitting electrode and a second resonate emitting electrode. The vehicle-mounted resonate receiving electrode comprises a first receiving electrode and a second receiving electrode which are separately placed at front and back ends of an electric vehicle. The section of an emitting coil of the resonate circuit is in the shape of long strip and arranged crossly; the section of a receiving coil in the vehicle-mounted resonate receiving electrode is in the shape of long strip and vertically arranged. Two receiving electrodes are under the mutual complementary state, namely, when one receiving electrode is under the high-efficient emitting scale of the magnetic coupling resonate emitting electrode, the receiving electrode is worked under the resonate power transmission state; the other one receiving electrode is under the state of compensating the receiving electrode. Through reasonable design of the structure and the control strategy, the advancing continuous high-efficient wireless charging of the electric vehicle is realized.

The invention discloses an energy coupler applicable to a cosine grating-loaded folded waveguide slow-wave structure. The end surfaces, which are vertical to the axis of the slow-wave structure, of various gratings between adjacent straight waveguide sections in a folded waveguide, with a periodic structure, of the folded waveguide slow-wave structure have cosine profiles at one side of a waveguide connection segment. The energy coupler comprises a rectangular waveguide; andmetal ridges are formed on the rectangular waveguide corresponding to cosine profile gratings at one side of the cosine grating-loaded folded waveguide slow-wave structure. The energy coupler disclosed by the invention is simple in structure, and is connected with the input and output of the cosine grating-loaded folded waveguide slow-wave structure with a complicated structure to form a high-frequency system with the energy coupler, so that the effective input / output of an electromagnetic field from the rectangular waveguide can be achieved.

The invention discloses an RFID antenna impedance self-adaptive adjustment method under the severe conditions. The implementation of the method mainly comprises the following steps of input signal acquisition, phase difference measurement, phase difference judgment, capacitance compensation, read-write tag judgment and frequency compensation. RFID radio frequency chip and antenna side signals are mainly acquired in the input signal acquisition. Phase difference measurement and judgment are performed on the acquired signals. The capacitance meeting the requirement of phase difference is selected by the capacitance compensation so that radio frequency front-end antenna impedance matching can be realized. When tag reading and writing still fail under the condition that the phase difference meets the requirement, radio frequency front-end antenna impedance matching is realized by changing radio frequency chip transmitting frequency through the frequency compensation. The influence of high temperature, high pressure, mud media, metal environment and other severe conditions on RFID antenna impedance in low-frequency RFID communication can be mainly solved so that the method has important meaning in enhancing the reliability of RFID communication and then enhancing the efficiency of RFID communication.

The input terminal 101 is connected to the output terminal 102 via an open stub 107 , a main line 105 , an open stub 108 . The coupling terminal 103 is connected to the isolation terminal 104 through the sub-line 106 electromagnetically coupled with the main line 105 . Open stub 107 and open stub 108 have a stub length corresponding to 1 / 4 wavelength at the desired cutoff frequency. Thereby, even in the microwave to millimeter wave frequency band, it is possible to provide a directional coupler and a directional coupling method that are small in size, low in loss, and have good high-frequency spurious suppression characteristics.

The invention provides an ultra wide band plasma filter provided with an artificial surface. The ultra wide band plasma filter comprises a coaxial waveguide of which the two ends are symmetrical, a transitional waveguide from the coaxial waveguide to a cylindrical plasma waveguide, and the intermediate cylindrical plasma waveguide, wherein the transitional waveguide comprises an inner conductor transition and an outer conductor transition; the inner conductor transition is realized through a periodic ring-shaped groove array of which the radius and the depth change simultaneously; the outer conductor transition is realized through a horn antenna of which the opening changes gradually as a curve changes; the cylindrical plasma waveguide consists of the periodic ring-shaped groove array of which the radius and the depth are constant. The ultra wide band plasma filter provided by the invention has an open symmetrical structure, the compact size, the wide band, a high performance and a simple structure, is especially suitable for being used with a traditional microwave or a terahertz transmission line in a matching manner, can be used as the novel wide band plasma filter, and provides a fire-new thought and scheme for the design and the application of the filter.

The invention relates to an impedance matching method of a plasma etching system. The impedance method comprises the steps of providing a plasma etching system, wherein the plasma etching system comprises an impedance matching device, the input end of the impedance matching device is electrically connected with a source power and a bias power supply, the output end of the impedance matching device is electrically connected with a reaction cavity, the end, connected with the source power, of the impedance matching device is electrically connected with one end of a voltage-current detector, and the other end of the voltage-current detector is connected with the source power through a frequency regulation control unit; the source power and the bias power supply simultaneously work under a continuous power mode, and a first matching frequency can be obtained by adjusting the frequency of the source power; the bias power supply is converted into a pulse power mode, and the first matching frequency serves as a benchmark frequency of the source power under a bias power supply pulse opening state, and when the bias power supply is converted to a pulse closing state from the pulse opening state, the benchmark frequency is adopted as the benchmark, so that a second matching frequency can be obtained by increasing or reducing the frequency of the source power.

The invention discloses a ball grid array millimeter wave broadband matching structure in wafer-level packaging and a design method, and belongs to the technical field of microwave and millimeter wavepackaging circuit systems. A first branch signal line, a multistage stepped impedance resonator and a front-end circuit transmission line are sequentially connected with an upper surface of a microwave dielectric substrate in the positive direction of the x axis, a central signal BGA solder ball connection structure outputs millimeter wave signals, the signals are transmitted to a multi-stage stepped impedance resonator through a first branch signal line to realize broadband matching, the signals are transmitted to a front-end circuit transmission line for output by the multi-stage stepped impedance resonator, broadband matching between the central signal BGA solder ball connection structure and the front-end circuit transmission line is realized, a problem that impedance between a silicon through hole BGA interconnection impedance compensation structure and the front-end circuit signal line is not matched due to the fact that the size of the bottom of a BGA solder ball is larger thanthe width of a signal line of a front-end circuit of a microwave dielectric substrate in the silicon through hole BGA interconnection impedance compensation structure in three-dimensional wafer levelpackaging is solved.

The invention provides a medium / low-frequency impedance adjusting device and an impedance matching system comprising the same, which can ensure that the impedance of a load and the impedance adjusting device is conjugate and matched with the characteristic impedance of a power supply. The device comprises a transformer and a capacitor C1, wherein the transformer is orderly connected with the capacitor C1 and the load to form a circuit. The transformer (the ratio of the number of turns of a primary coil to the number of turns of a secondary coil) and a capacitance value of the capacitor C1 are adjusted, so that impedance matching between the impedance of the load and the impedance adjusting device and the characteristic impedance of the power supply can be realized to further load the power of the medium / low-frequency power supply to the load and avoids power loss.

The invention discloses a method for preparing a carbon nano spiral electromagnetic wave absorbent coated by a magnetic material. The method comprises the following steps of: pyrolyzing copper carboxylate at a high temperature to obtain copper nano particles, and carrying out a chemical vapor deposition reaction to obtain a carbon nano spiral by using the copper nano particles as a catalyst and acetylene as a carbon source; dispersing the carbon nano spiral on a quartz plate, putting the quartz plate into a reaction cavity of an atom layer deposition device and implementing the deposition of an Al2O3 protection film; directly implementing the deposition of a metal oxide Fe2O3 or NiO to the carbon nano spiral protected by an aluminum oxide film, reducing the carbon nano spiral product coated by Fe2O3 or NiO in a mixture atmosphere of H2 and N2, thereby obtaining a carbon nano spiral coated by a magnetic Fe3O4 or Ni coating. The method disclosed by the invention has the advantages of simple process and easiness for control.

The invention belongs to the field of composite material manufacturing and structure microwave-absorbing materials, and relates to a microwave-absorbing composite material with a discontinuous impedance gradient structure. A five-layer discontinuous impedance gradient structure comprising a wave-transparent layer, a low-concentration electrical loss layer, another wave-transparent layer and a high-concentration electrical loss layer and yet another wave-transparent layer is adopted; the used absorbent is electrical loss absorbent short carbon fibers; a mixed liquid is sprayed on quartz glass fiber cloth by adopting a spraying technology; and the short carbon fibers are uniformly distributed. An impedance gradient structure design is adopted by the electrical loss microwave-absorbing composite material, impedance matching can be achieved and an absorption band is effectively expanded. The short carbon fibers have the advantages of light weight, diversified loss mechanism and relatively high electromagnetic wave loss ability as an electrical loss absorbent, and the weight of the microwave-absorbing composite material is not increased. The designed and manufactured microwave-absorbing composite material has good micro-wave absorbing ability on X and KU bands.

The invention discloses an ultra-high-frequency sensor for monitoring partial discharge in a switch cabinet online. The ultra-high-frequency sensor comprises a micro-strip slot antenna and an SMA (Sub-Miniature A) connector, wherein the micro-strip slot antenna comprises a dielectric substrate, wherein a grooved metal grounding plate is arranged on one side of the dielectric substrate, and the micro-strip slot antenna is arranged on the opposite side of the dielectric substrate; the SMA connector is electrically connected with the micro-strip slot antenna. From an overall perspective, the shape of the groove in the metal grounding plate is an inverted U shape; a detail design adopts a meander technology, and the path of exciting current on the surface of the metal grounding plate is changed by bending, so that the miniaturization of an antenna is realized. In application, the ultra-high-frequency sensor is light in weight, small in size and easy to manufacture, and is beneficial to be arranged in the switch cabinet; meanwhile, the sensitivity is high; a feed structure is simple and compact; the loss of a feed line is low. Simulation and experiments prove that the return loss of the sensor in a bandwidth range is less than -10 dB; in addition, the impedance matching with a standard 50-Ohm coaxial transmission line is effectively realized by optimizing micro-strip feed line parameters and feed positions.

The invention discloses a three-dimensional packaging device for a photonic integrated chip matching circuit. The three-dimensional packaging device comprises a first carrier substrate, a first microwave transmission line array, a second carrier substrate, a second microwave transmission line array, an electrode array and a microwave circuit, wherein the first microwave transmission line array is evaporated on the upper surface of the first carrier substrate and used for providing bias voltage and high-frequency modulating signals for photonic integrated chips; the second carrier substrate is perpendicular to the first carrier substrate or forms a certain angle with the same so that a three-dimensional stereoscopic structure is formed; the second microwave transmission line array is evaporated on the lower surface of the second carrier substrate and is matched with an electrode of the first microwave transmission line array by welding or sintering; and the electrode array is evaporated on one side face or two opposite side faces of the second carrier substrate. The three-dimensional packaging device for the photonic integrated chip matching circuit solves the problem that a matching circuit is limited in size due to limitation on array chip spacing during integrated chip array packaging and breaks through limitations that a microwave circuit is just in a two-dimensional plane in traditional design, dimensionality of circuit design is increased, and space for designing the microwave circuit is reserved.

The invention discloses a four-arm spiral antenna. The four-arm spiral antenna comprises a spiral arm, and the spiral arm comprises a first spiral arm portion, at least one second spiral arm portion arranged at an interval from the first spiral arm portion, and a third spiral arm portion, wherein one end of the first spiral arm portion and one end of the second spiral arm portion are connected with one end of the third spiral arm portion, and the other end of the third spiral arm portion is connected with a spiral arm feed end feeding the spiral arm. The spiral antenna provided by the invention can realize multi-frequency-range work of more than two frequency ranges with quite large frequency intervals and can also adjust input impedance of the spiral antenna through structural adjustment of the spiral arm of the spiral antenna so as to realize impedance match between an input port and a feed pot, reduce energy loss and improve the overall gain of the antenna. The spiral antenna provided by the invention is compact in structure, light in weight, small in volume and easy to process.

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 voltage-control adjustable film inductance. Wherein, on the piezoelectric ceramic substrate, it prepares film inductance with magnetic layer; uses the inverse piezoelectric effect of piezoelectric ceramic and the inverse magnetic flexible effect of magnetic film, via external voltage, to adjust the deformation of substrate and change the magnetic conductivity of magnetic film, to adjust the inductance. The invention can be used in movable communicator, T / R element, GPS, etc.

The invention belongs to the technical field of a sound barrier acoustic member, and specifically relates to a cup-shaped noise reduction and sound absorption member of a sound barrier. The cup-shaped noise reduction and sound absorption member is composed of a plurality of cup-shaped noise reduction and sound absorption member units, wherein a panel of each unit is composed of a plurality of rectangular arrays and trapezoidal transverse bars; each rectangular array is composed of a plurality of uniformly distributed reflector cups with a paraboloid-shaped acoustic construction; diffraction holes are formed in the bottom of each reflector cup; a rectangular connecting groove is respectively arranged in the longitudinal center on the upper surface and the lower surface of a back plate of each unit; the connecting groove and the rectangular connecting grooves of other sound absorption member units in the same position form a square cavity during installation, wherein a square steel pipe is embedded in the cavity as a connecting piece for clamping two adjacent cup-shaped noise reduction and sound absorption member units; a sound insulation plate is mounted in a tubular cavity which is formed by connecting the panel and the back plate; support frames are arranged on the transverse bars inside the cavity; and spaces divided by the support frame are filled with sound absorption wools and gauzes. The cup-shaped noise reduction and sound absorption member has stronger sound absorption ability, and the low-frequency sound absorption ability is improved.

An antenna structure (106) comprising a first electrically conductive element (102) having a first end and a second end, a second electrically conductive element (103) having a first end and a second end, and a coupling structure (104) short- circuiting the first electrically conductive element (102) with the second electrically conductive element (103) by means of electrically connecting the electrically conductive elements (102, 103) at positions between the first and the second ends, wherein an integrated circuit (105) is connectable between the first end of the first electrically conductive element (102) and the first end of the second electrically conductive element (103).

A double-layer printed-circuit board capable of realizing the impedance control comprises a dielectric layer and several high-speed signal transmission lines and a ground plane adjacent to each high-speed signal transmission line on the dielectric layer. Using the said double-layer printed-circuit board can input the two-dimensional sectional graphic of the double-layer printed-circuit board to an artificial software. An ideal characteristic impedance value is obtained via the multiple adjustment of parameter value of the said high-speed signal transmission line and the relative location of the high-speed signal transmission line and the ground plane, the multiple input of the two-dimensional graphic and the multiple computation of the artificial software after comparing the characteristic impedance value of the high-speed signal transmission line counted by the artificial software and its standard impedance value.

The invention discloses a microwave single-pole multi-throw switch which comprises an input transmission line. One end of the input transmission line serves as an input end, the other end of the input transmission line at the same time is connected to a switch group and a compensating circuit; the switch group is composed of at least two switch arms, and the other end of each switch arm serves as an output end; and the compensating circuit changes an input impedance of the switch group, so that the switch group and the input transmission line are matched in terms of the impedance. In the invention, based on a single-pole double-throw switch, a plurality of switch arms adds to constitute the single-pole multi-throw switch. At the same time, the plurality of switch arms are connected in parallel with the compensating circuit, and the compensating circuit is composed of a reactive component capacitor and / or an inductor group. When the microwave single-pole multi-throw switch is in actual use, the inductor and capacitor in the compensating circuit is enabled to choose the appropriate capacitance and inductance values, so as to realize the impedance matching between the switch arms and the input source and the input transmission line.