497results about How to "Working frequency bandwidth" patented technology

The invention introduces a microwave device impedance measurement calibration method. The method comprises the following steps: (1), calculating time-delay transmission line transmission parameters through real-time measured data of straight-through calibration member scattering parameters and time-delay calibration member scattering parameters; (2), embedding a newly added virtual transmission line in an original time-delay calibration member, and calculating the transmission parameters of a virtual time-delay calibration member; (3), according to a conventional TRL calibration method, extracting calibration coefficients of a measuring clamp, and performing matrix inversion and multiplication operation to obtain a microwave device de-embedding transmission parameters; and (4), performing impedance normalization transformation on the microwave device de-embedding transmission parameters to obtain normalized microwave device normalization scattering parameters relative to system measurement reference impedance. The method makes up the measurement errors caused by inconsistence of transmission line characteristic impedance and the system measurement reference impedance, and realizes microwave device impedance measurement with an ultra wide band and high precision. At the same time, the improved microwave device impedance measurement calibration method can substantially reduce design processing requirements of a calibration device, thereby having high versatility.

The invention relates to a method for testing the complex dielectric constant of microwave dielectric material and belongs to the field of microwave testing technology. The method comprises the following steps: firstly, processing the microwave dielectric material to be measured into a rectangular thin slice with two parallel surfaces and simultaneously preparing two dielectric material supporting blocks and two metal conduction strips, then forming a double-sided parallel strip line resonator, inputting a microwave frequency sweep test signal into the double-sided parallel strip line resonator through a coaxial coupling probe, measuring the resonant frequency fr and the loaded quality factors QL after the microwave frequency sweep test signal passes through the double-sided parallel strip line resonator and combing the known parameters (Relevant dimension, complex dielectric constants of the dielectric material supporting blocks and the like) to calculate the complex dielectric constant of the microwave dielectric material to the measured. The method has the advantages of wide working frequency band, small volume of a test device, good mixed mode rejection, small test error and the like and is convenient to use. The invention can realize the wide-scope, accurate and quick noninvasive measurement to the complex dielectric constant of the microwave dielectric material within the scope of each microwave frequency band.

The invention provides a single-frequency network-based passive radar system and a signal processing method for the same. A plurality of illumination sources for the system are used for simultaneously transmitting the same signals at the same frequency, and namely work in a single-frequency network system. A plurality of transmission stations and one or more receiving stations form a MISO (multiple-input single-output) or MIMO (multiple-input multiple-output) detection system, wherein the MIMO system is provided with a fusion center for performing communication and data transmission with each receiving station through a communication link and fusing processing results of each receiving station, and works at the same frequency; each transmission station is in the same form, and each receiving station is in the same form. A one-stop space-domain processing and single-frequency network defuzzification method is adopted for the signal processing method. According to the system and the method, a conventional broadcasting single-frequency network is used under the condition of no interference on broadcasting, so that the problems of severe clutter caused by the single-frequency network and fuzziness of the single-frequency network are solved, and the advantages of single-frequency network detection in frequency power reduction, hardware saving, detection stability and tracking continuity are fully exerted.

The utility model discloses a leakage current sensor with high precision broadband pollution insulator, relating to an insulator AC leakage current detection sensor. The sensor of the utility model mainly comprises Rogowski coil and an integral amplifying unit and a coaxial cable; the Rogowski coil and the integral amplifying unit are connected through the coaxial cable. The utility model has the advantages of strongly anti-interfering ability, high detecting precision, sensibility up to 8.3mV/mA, bandwidth up to 2Hz to 100kHz, amplitude range of detecting current reaching 10MuA to 450mA; thus the utility model is widely used in online monitoring of insulator leakage current of power transmission line and transformer station and is also used for micro-current or small current monitoring of other electrical and electronic devices such as grounding current, leakage current and harmonic current.

The invention provides a liquid metal-based air-control deformable antenna. The liquid metal-based air-control deformable antenna comprises a flexible runner, liquid metal, an airbag and an air pump, wherein the liquid metal and the airbag are both arranged in the flexible runner; and the air pump is arranged on the exterior of the flexible runner and used for air inflation or air suction for the airbag. By inflating the airbag to expand the airbag, movement of the liquid metal in the flexible runner is pushed to form a specific shape; by inflating different airbags, volumes and shapes are changed, so that changes of the liquid metal antenna position, changes of the antenna diameter, changes of the antenna lengths, and changes of antenna tilted angle can be realized; the diameter and length of the air-control are relatively large in a changeable range, so that a relatively wide frequency band can be provided; and in addition, liquid metal material has mobility, so that cracking of the antenna can be prevented, and self recovery capability is achieved.

The invention discloses a broadband bionic yagi antenna with a low radar cross section and mainly solves the problems of high radar cross section and relatively narrow band width in the traditional yagi antenna. The antenna simulates an opposite phyllotaxis plant leaf structure and comprises a director (2), a radiating element (3), a parallel strip line (4), a reflector (5) and a coaxial conversion joint (6). The radiating element (3) is of an oval structure, the director (2) simulates a feather-shaped leaf structure, and the reflector (4) is a rectangle patch with a tooth-shaped structure. The radiating element (3) is printed on a top layer and a bottom layer of a double-layer medium material plate (1) and respectively connected with an inner core and an outer core of the coaxial conversion joint (6) by the parallel strip line (4); the director (2) is printed on the top layer of the double-layer medium material plate (1); and the reflector (4) is printed between two layers of the double-layer medium material plate (1). The broadband bionic yagi antenna with the low radar cross section has the advantages of wide frequency band and good invisibility performance and can be used on an invisible target carrier.

The invention relates to a broadband radial pattern leaky coaxial cable used for subway and a manufacturing method thereof, and the leaky coaxial cable has the double functions of transmission line of information and duplexer. The structure of the leaky coaxial cable consists of an inner conductor, an insulation layer, an outer conductor and a jacket, wherein, the inner conductor is externally covered with the insulation layer which is externally covered with the outer conductor that is externally sheathed with the jacket, and the insulation layer that covers on the surface of the inner conductor adopts nitrogen or carbon dioxide physical foam to form a foamed polyethylene insulation layer; cambered slotted holes are opened on a clutch gold belt of the outer conductor covered outside the insulation layer. The manufacturing method comprises the steps: (1) a spiral wrinkle inner conductor is manufactured by longitudinal covering welding and embossing by using a copper strip; (2) the nitrogen or the carbon dioxide are adopted to be injected into the smelted polyvinyl plastics, and then the physical foamed polyethylene insulation layer is formed on the surface of the inner conductor by extrusion and cladding; (3) the slotted holes broken out by the clutch gold belt of the outer conductor are the cambered slotted holes; (4) the clutch gold belt of the outer conductor is covered on the insulation layer longitudinally, and the surface of the clutch gold belt of the outer conductor is crowded and covered with the jacket.

This invention discloses a broadband symmetrical vibrator antenna different from that of ordinary structures composed of a radiator, a reflector, a supply micro-strip wire, a supply coaxial wire, a parasitic unit and a short circuit device characterizing in utilizing an arm of a plane symmetrical vibrator to constitute an earth surface of the supply micro-strip wire and the coaxial wire to realize broadband balanced supply, which has fine matched property in 2-3 frequency multiplications suitable for VHF/UHF bands, especially for the broadband array antennas with reflectors.

The invention discloses a method for reducing heat of a hypersonic velocity aircraft based on shock wave control, and relates to the fields of flowing control of hydromechanics and plasma physical application. The method comprises the following steps of using a high-pressure gas source gas spraying device or a plasma synthesizing flow jetting device to control shock waves in a hypersonic velocity aircraft flow field, lifting the leading head shock wave of the hypersonic velocity aircraft, and eliminating the leading shock of side wings, or producing reciprocating swinging, so as to eliminate or control the shock wave disturbance area, reduce the heat flow in key periods and key areas, and realize the heat protection of the aircraft. The method has the advantages that by adopting the outer flow field control type, the root produced by high heat flow is prevented or controlled, and the heat reducing and protection can be realized by reducing the production of heat flow in source; compared with the traditional method of performing passive heat protection on the cause of high heat flow, the material revolution is realized, and a new active heat protection control technique is realized.

The invention discloses a high-frequency conversion structure with a rectangular-circular mode, relating to microwave technology. In the high-frequency conversion structure, a rectangular waveguide is orthogonally connected with a circular waveguide; one end of the circular waveguide is connected with a circular waveguide drift section which is closed aiming to a TE11 mode in an operating mode, and the other end of the circular waveguide is sequentially connected with a first tapering circular waveguide, an elliptical waveguide, a second tapering circular waveguide and an output circular waveguide; and the output circular waveguide is used for outputting waves in a TE11 circularly-polarized mode. The invention provides a novel method for converting rectangular waveguides from a TE10 linearly-polarized mode to an operating-mode TE11 circularly-polarized mode, therefore, the input coupling problem of a gyrotron amplifier is solved.

The invention discloses a three-frequency-range common-caliber active navigation antenna, for solving the problems of not wide enough work frequency band of a conventional navigation antenna, low radiation efficiency and low elevation angle gain of a directional diagram. The three-frequency-range common-caliber active navigation antenna comprises a common-caliber antenna unit (1), a filter (2), a low-noise amplifier (3) and a back cavity (4). The common-caliber antenna unit (1) comprises a high-frequency radiator, an intermediate frequency radiator and a low frequency radiator, the three radiators are successively laminated from top to bottom, and the high frequency radiator and the low frequency radiator employ capacitance coupling feed and introduce parasitic patches; the filter (2) and the low-noise amplifier (3) are disposed below the common-caliber antenna unit (1) and are installed in the cavity of the back cavity (4); and the common-caliber antenna unit (1), the filter (2) and the low-noise amplifier (3) are successively connected. The three-frequency-range common-caliber active navigation antenna can realize multiplexing of antennas of three system frequency ranges and also has the advantages of wide work frequency band and good radiation characteristic, thereby being applied to reception of signals of a satellite navigation system.

The invention discloses a time division-long term evolution (TD-LTE) dual-polarization radiation unit, which comprises symmetrical vibrator radiation arms, feed baluns and supporting arms, wherein the number of the symmetrical vibrator radiation arms is two pairs, and the two pairs of symmetrical vibrator radiation arms are distributed across; each pair of symmetrical vibrator radiation arms is fixed on a floor through the supporting arms respectively; and the number of the feed baluns is 2, one end of each feed balun is connected with one of the corresponding symmetrical vibrator radiation arm, and the other end of the feed balun is fixed at the bottom of the supporting arm of the other one of the corresponding symmetrical vibrator radiation arm. Because two pairs of symmetrical vibrators form an integrated structure, the dual-polarization radiation unit has electric properties such as high gain, wide working bandwidth, high isolation degree, low cross polarization level and the like.

The invention relates to a high gain broadband dielectric lens Vivaldi antenna. The array antenna comprises a substrate, a radiation slot, a dielectric lens and a Chebychev tapered strip line feeder. According to the high gain broadband dielectric lens Vivaldi antenna, through changing the structural size of the dielectric lens, the fluctuation of antenna radiation impedance can be effectively improved so as to obtain better impedance matching, the transmission speed of an electromagnetic wave in the slot can be reduced according to the high dielectric constant of the lens, the current distribution on an antenna aperture is improved, thus a spherical wave is a nearly a plane wave, the antenna radiation efficiency is raised, and a higher antenna gain is obtained. According to a Chebychev tapered strip line, the impedance matching of the antenna can be improved further, and the working band is broadened. The array antenna in the invention has the characteristics of high gain and broad band and is suitable for a radiation unit of wideband array antennas of the field of mobile communication and a military radar.

The invention relates to a dielectric-loaded based ultra wide band compact field feed source. The ultra wide band compact field feed source comprises an improved dielectric-loaded horn antenna (1), a supporting column (2), a flange plate (3) and a wave-absorbing material (4), wherein a ridge waveguide part is matched with a ridge curve of a horn for increasing the thickness of a ridge (5) to the maximum; two semi rigid coaxial cable electric connectors connected by an SMA connector are adopted as feed probes, and the diameter of the cable is less than 2 mm; the two feed probes are perpendicularly mounted, and are corresponding to two polarities of the feed source respectively; the radiation electric field of the feed source antenna can be concentrated to a dielectric region as far as possible by optimizing the shape of the dielectric-loaded material and the relative position of a four-ridge horn antenna for stabilizing the phase center; the supporting column of a certain length is arranged behind the dielectric-loaded horn antenna to enable the dielectric-loaded horn antenna aperture to be far from a feed source bracket; the wave-absorbing material of a specific size is added at the bottom of the supporting column for restraining multiple times of radiation caused by a complex metal structure of the feed source bracket; and the dielectric-loaded based ultra wide band compact field feed source has the outstanding advantages of small size, light quality and low cost.

The invention relates to the field of vibration application and electric power technology, and particularly to a right-angled piezoelectric cantilever beam vibration energy harvester. The right-angled piezoelectric cantilever beam vibration energy harvester comprises a supporting base and a horizontal metal substrate which is mounted on the supporting base. The horizontal metal substrate is provided with a piezoelectric ceramic wafer at the end which is next to the supporting base. A vertical metal substrate is adhered to the other end of the horizontal metal substrate. The horizontal metal substrate is perpendicular with a vertical metal substrate, thereby forming a right-angled cantilever beam structure. The other end of the vertical metal substrate is provided with a mass block. According to the right-angled piezoelectric cantilever beam vibration energy harvester, the right-angled cantilever beam is formed through adding an auxiliary cantilever beam at the end of the horizontal cantilever beam. Through controlling the structural dimensions of the horizontal cantilever beam and the vertical cantilever beam and the mass of the mass block, controlling for an interval between two front stages of modal frequencies is realized, thereby forming a relatively wide operation frequency band and realizing high-efficiency acquisition and conversion for environment vibration energy.

The invention discloses a piezoelectric energy collector based on a linear resonator and a nonlinear vibration exciter. The piezoelectric energy collector comprises an energy collecting structure and an energy collecting circuit, wherein the energy collecting structure comprises a piezoelectric cantilever beam, the linear resonator and the nonlinear vibration exciter. According to the piezoelectric energy collector, the linear resonator is further arranged on the piezoelectric cantilever beam, so that two resonance peaks which are close to each other are obtained, and a reverse resonance peak of the energy collector can be further moved outside of the two resonance peaks through designing parameters such as the mass ratio, the frequency ratio and the position ratio of the linear resonator and the piezoelectric cantilever beam, so that a wider working band can be obtained; the arrangement of the nonlinear vibration exciter can increase the number of the resonance peaks of a system, and the working band of the system can be further expanded through designing system parameters, or the performance at a valley between the two resonance peaks can be improved.

The invention relates to an RFID (radiofrequency identification) tag applied to intensive distribution scenarios and a mutual impedance design method thereof. The RFID tag designed comprises a dielectric substrate, a metal microstrip antenna and a chip; the metal microstrip antenna and the chip are arranged on the dielectric substrate. The metal microstrip antenna is composed of a pair of radiation patches, a pair of bent radiation arms and a resonant matching ring. The radiation patches are in a rectangular shape. The bent radiation arms are in an M shape; 10 folds are made on each side of the bent radiation arms. The resonant matching ring is U shaped; two vertical arms of the resonant matching ring are connected with a feeder; the feeder is welded to an anode and a cathode of the chip and connected in a single-port manner. By the use of the mutual impedance design method to the RFID tags, mutual coupling of RFID tags is decreased. The RFID tag has a maximum transmission coefficient 0.8, a maximum gain 2.28dbi and a longest reading distance 10m under operating frequencies; the RFID tag has a wider range of coverage. Under the frequency 920MHz, the RFID tags spaced by 2mm generate mutual impedance less than 50ohm; a good capacity to recognize multiple RFID tags is provided.

An 18-40GHz double balanced mixer in structure belongs to the microwave and millimeter wave technical field and relates to a double balanced mixer in star structure. The mixer comprises a double ridge waveguide and a hybrid circuit board and an intermediate frequency output terminal which are arranged on the plane E at the center of the double ridge waveguide. In the invention, the height of the two ridges of the 18-40GHz double ridge waveguide is linearly decreased in a gradient way, thus being convenient for installing diodes and being beneficial to improving impedance matching between a fin line and a coplanar strip line; when leading the intermediate frequency out, an inner conductor passes through a medium substrate and extends to the interior of a cavity and close to the wall of the cavity, so as to improve the symmetrical characteristic of an LO and RF signal field structure, thus improving the balance of four diodes, frequency conversion loss and insulation between an LO signal and an RF signal; a bead is adopted to lead the intermediate frequency out, installation is convenient, and reliability is good; and a boss is additionally arranged at the lead out point of the intermediate frequency at the narrow side of the ridge waveguide, thus being beneficial to improving intermediate frequency bandwidth. The invention has the advantages of wide working band, small size, low frequency conversion loss and high insulation and has a favourable application prospect in an ultra wide band transceiver.

The invention discloses a design method for a pure medium electromagnetic lens based on a meta-surface. The method includes the following steps that firstly, according to medium materials of the lens and the wavelength of working electromagnetic waves, the relation between phase changes and medium thicknesses is obtained; secondly, according to requirements for the type and focal length of the lens (a convex lens or a concave lens or a reflecting mirror), needed distribution of phase jumps is worked out; thirdly, according to phase distribution requirements, the medium lens with the corresponding thickness is established in electromagnetic simulation software, is simulated and finely adjusted and then can be manufactured, wherein the phase distribution phi is obtained according to the requirement of the lens designed in the second step, distribution of the medium thicknesses is worked out, and modeling and simulating are conducted in the electromagnetic simulation software. The design method is simple and flexible; along with reduction of incidence wavelengths, the focal length of the lens will be increased; a lens set composed of the lens and a traditional lens can eliminate chromatic aberration.