142results about How to "With broadband characteristics" patented technology

The invention relates to a lens antenna which comprises a metal loudspeaker (4) and a lens (1), wherein the metal loudspeaker (4) is provided with a feed source; the feed source is embedded in the smaller-diameter end of the metal loudspeaker (4), and the lens (1) is embedded in the larger-diameter end of the metal loudspeaker (4); the lens (1) comprises a core plate (2); the core plate (2) is a planar dielectric plate, and one of the planes is provided with a plurality of core-plate disresonance basic units; a core-plate metal square frame (5) is printed in each core-plate disresonance basicunit; and the areas of the core-plate disresonance basic units and the core-plate metal square frames (5) gradually decrease from the center to the edge of the core plate (2). As the core plate (2) is planar, the lens (1) is easy to manufacture. In addition, the lens (1) also comprises matching plates (3) positioned on both sides of the core plate (2). The matching plates (3) can reduce the reflection of the electromagnetic waves on the interface of the lens (1) and the air.

The invention relates to a system for calibrating receiving performance of a partial-discharge ultrahigh frequency detection device, and the system comprises a giagahertz transverse electromagnetic cell (GTEM) transmission cell, a standard pulse generator, a measure and control computer and a high-speed broadband oscillator, which are sequentially connected with one another through a conducting wire, wherein the high-speed broadband oscillator transmits a branch signal to the GTEM transmission cell, the top of the GTEM transmission cell is provided with a special test window which is provided with a reference sensor and a tested sensor, and the reference sensor and the tested sensor are respectively connected with the high-speed broadband oscillator. The invention also relates to a calibration method by adopting the system. The calibration system and the calibration method have a broadband property and low cost, and not only can be used for electromagnetic radiation sensitivity test, but also can be used for the electromagnetic radiation test; and moreover, the instruments used in the system and the method are simple to configure, low in cost and capable of being used for rapid and automatic test.

The invention discloses a multi-spectral phase-type metasurface device and belongs to the metamaterial technical field. The multi-spectral phase-type metasurface device of the invention is composed of a nano unit structure array which is formed on ultra-thin metal or a medium through etching. According to the multi-spectral phase-type metasurface device of the invention, multi-frequency information is coded onto a metasurface; and phase regulation can be performed on electromagnetic waves of a plurality of wavelengths by using wide-band spin-orbit interaction of nanostructures on the metasurface, so that the electromagnetic waves with different wavelengths and different incident angles can be focused to a specific shape. Therefore, the multi-spectral phase-type metasurface device of the invention can be applied to the design of a multi-wavelength ultra-small optical device and an integrated optical system.

The invention discloses a transparent broadband metamaterial absorber which comprises multiple periodically arranged unit structures. Each of the unit structures comprises an upper layer transparent resonant structure at the center of the unit structure, a middle layer transparent substrate, and a lower layer transparent reflection layer. The upper layer transparent resonant structure is above the middle transparent substrate, and the lower layer transparent reflection layer is under the middle layer transparent substrate. The upper layer transparent resonant structure is a symmetric figure which comprises a ring and a ring with a branch at the periphery of the ring. Both the upper layer transparent resonant structure and the lower layer transparent reflection layer are transparent conductive materials. According to the transparent broadband metamaterial absorber, the reflection rate of incident electromagnetic wave can be effectively attenuated in an X band, the transparent broadband metamaterial absorber is convenient to manufacture, the technology is mature, the light transmittance performance of the overall structure is excellent and a light transmittance rate is larger than or equal to 80% in a visible light range, and the transparent broadband metamaterial absorber has a good prospect in application.

The invention discloses a broadband antenna and a wireless communication device. The wireless communication device with an outer metal frame of the broadband antenna comprises a radiating body, a fixing point, a feed element and a parasitic radiating body. The radiating body is used for receiving and transmitting a radio-frequency signal and coupled to a grounding portion through the fixing point. The feed element is electrically connected between the radiating body and the grounding portion and used for feeding the radio-frequency signal to the radiating body. The parasitic radiating body is electrically connected to the grounding portion. A first distance is formed between the parasitic radiating body and the radiating body. The parasitic radiating body is one part of the outer metal frame. Coupling effect between the parasitic radiating body and the radiating body is generated due to the first distance so as to form a coupling antenna used for receiving and transmitting the radio-frequency signal.

The invention discloses a low-frequency multidirectional vibration energy recovery device, which comprises a mass block and an outer frame, wherein the mass block is positioned in the outer frame; the mass block is connected with the outer frame by foldable elastic beams; each foldable elastic beam is provided with a piezoelectric sheet; the periphery of the mass block is provided with the foldable elastic beams with the same folding mode; and the folding mode of the foldable elastic beams is characterized by folding by layers from outside to inside and decreasing the folding length progressively. The device can be used for low-frequency vibration energy recovery in various large machine engine bases or vibration elements, automobile engines, blenders, washing machines and various micro-structures, and can provide electric power for various types of portable equipment, wireless sensors and micro electro mechanical systems.

The invention discloses a beam controllable Vivaldi antenna. The antenna comprises a dielectric substrate and a copper foil which covers the dielectric substrate and comprises a horn-shaped opening. A cylindrical lens is arranged at the horn-shaped opening. The lens comprises two parts along a longitudinal direction. The refractive index of the first part of the lens is 1-1.1. The refractive index of the second part of the lens is shown as an equation in the specification, wherein x represents the position of a horizontal ordinate by taking the circle centre of the lens as the origin of a coordinate axis; and y represents the position of a vertical ordinate by taking the circle centre of the lens as the origin of the coordinate axis. After translating for 14 mm along the horizontal ordinate direction of the coordinate axis, the circle centre of the lens and a space in which the original lens is located form an interface which is a separating surface of the first part and the second part. The antenna disclosed by the invention has the advantages of simplicity for manufacture and convenience for processing. The traditional beam control is generally realized by using a plurality of antennas to form a phase array, thus, the complexity of a system is increased and the manufacture process is fussy, but, the refractive index of an equivalent medium can be adjusted and controlled conveniently by utilizing a perforated dielectric slab, therefore, the requirements of the lens can be satisfied.

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 present invention discloses a method for extracting efficient small-signal equivalent circuit model parameters based on a gallium nitride high-electron-mobility transistor (GaN HEMT) and belongs to the field of power devices. The method, for error accumulation problems in conventional parameter extraction methods, based on a GaN HEMT 20-element small-signal model, provides an iterative algorithm, which is implemented in Matlab by programming. In an iterative process, the algorithm uses a more accurate element value than a previous element value each time for calculation, thereby leading a result to tend to an optimal solution. Compared with the conventional parameter extraction methods, the method can accurately fit S-parameters of a GaN HEMT device under full bias by running a Matlab program once, thereby obtaining all parameters of an equivalent circuit model, greatly reducing human labor in a parameter extraction process, and greatly improving the efficiency of device modeling.

The invention discloses an electromagnetic code basic unit with a self-adaptive function and a metamaterial. The metamaterial comprises N*N 2-bit programmable coding units, wherein N is a non-zero positive integer, an intelligent metamaterial unit structure comprises a metal structure layer, a surface-layer control diode, a dielectric plate layer, a total-reflection zero-transmission layer and a dielectric plate layer, all units can be used for achieving synchronous and independent real-time control by a programmable gate array, and four coding states can be generated and are corresponding tofour reflection phases of 0 degree, 90 degrees, 180 degrees and 270 degrees. The intelligent metamaterial is used for sensing position and angle of the metamaterial by a spectrometer, various types ofapplication such as beam deflection, special-mode orbital angular momentum beam and target radar cross section (RCS) reduction can be generated according to program setting in advance, so that the metamaterial is used for generating different electromagnetic responses under a special space state. The metamaterial has the advantages of simple-layer structure and the like and is easy to process.

The invention discloses a method for achieving wavefront modulation based on a dielectric conformal metasurface, and belongs to the technical field of micro-nano optics and holography. The implementation method comprises the following steps of designing a unit structure of the metasurface, wherein the metasurface is composed of dielectric circular nanopillar arrays with different geometric sizes,and by changing the geometric radius and height of a nanopillar unit, the phase of an emergent light beam is randomly adjusted and controlled by the metasurface; when a single curved surface is considered only, calculating out phase distribution phi 0 of incident light passing the curved surface according to a ray tracing method or a finite-different time-domain (FDTD) method, and then calculatingout phase distribution phi d of user-customized functions according to a diffraction theory or a holographic principle analysis method, thereby compensating a phase difference phi p of the two by using the dielectric conformal metasurface; and carrying out coding on the phase of the metasurface. The user-customized functions include lens focusing, adjustable abnormal refraction, optical camouflage and illusion functions. According to the method, the corresponding technical problems in the field of wearable electronic products, medical equipment or photoelectric devices can be solved.

The invention discloses a fractal acoustic metamaterial based broadband acoustic focusing lens and a preparation method thereof. The broadband acoustic focusing lens comprises a base material and a fractal structure unit array located on the base material. The fractal structure unit array is formed by arranging a plurality of fractal periodic units, and each fractal periodic unit corresponds to a refraction point of the focusing lens. The fractal period unit comprises a fractal unit and air, and a refractive index of the fractal unit corresponding to any refraction point conforms to a theoretical refractive index of the refraction point. According to the invention, the fractal units are adopted for the first time to form the acoustic focusing lens, thereby providing a new way for designing a new material for the acoustic engineering. The actual path length of spreading of acoustic waves in a unit structure is increased in a fractal mode, and the refractive index of the unit structure is improved. The acoustic focusing lens disclosed by the invention has a broadband characteristic, and can realize a good focusing effect of the acoustic waves in the scope of a broad band.

The invention relates to a wideband log-periodic dipole array antenna for feeding a substrate integrated waveguide. An upper metal coating (2) is provided with an upper assembly line (5), upper feed source element antennae (7), an upper surface (9) of the substrate integrated waveguide, a microstrip taper transition line (6) and a 50-ohm output microstrip line (8) which are sequentially connected, wherein the upper assembly line (5) is connected with the upper surface (9) of the substrate integrated waveguide, the upper feed source element antennae (7) are respectively arranged at both sides of the upper assembly line (5); a lower metal coating (3) comprises a lower surface assembly line (11) of the log-periodic dipole array antenna, lower surface feed source element antennae (12), a lower surface (13) of the substrate integrated waveguide and a ground surface (14) of a microstrip line; the lower surface assembly line (11) of the log-periodic dipole array antenna is symmetric in parallel to the upper assembly line (5) of the log-periodic dipole array antenna, the lower surface feed source element antennae (12) are symmetric in cross to the upper feed source element antennae (7); and the lower surface (13) of the substrate integrated waveguide is symmetric to the upper surface (9) of the substrate integrated waveguide and is connected with the ground surface (14) of the microstrip line.

The invention discloses a broadband circularly polarized millimeter wave multi-feed multi-beam lens antenna. The antenna comprises a multi-port broadband circularly polarized planar feed antenna array(1) and a planar lens (2); a plane of the multi-port broadband circularly polarized planar feed antenna array (1) and a plane of the planar lens (2) are arranged in parallel; and a signal of the multi-port broadband circularly polarized planar feed antenna array (1) is output or received through the planar lens (2). A plurality of focal points are distributed on the planar lens (2) in a phase-shifting mode, and the planar lens is formed by arranging completely identical anisotropic unit structures (5) in a periodic mode. Each anisotropic unit structure (5) is composed of an upper-layer metalpatch (5a), a middle-layer metal patch (5b) and a lower-layer metal patch (5c). The antenna can realize a multi-feed multi-beam characteristic and has a wide application prospect in the aspects of wireless communication and satellite communication.

The invention, which belongs to the vacuum electronic technology field, relates to an input / output structure of a broadband phase shift travelling wave tube. The structure comprises six parts of waveguide type elements: a first double-ridge loading rectangular wave guide; a double-ridge loading rectangular wave guide, which is in a bending state of 90 degrees; a second double-ridge loading rectangular wave guide; a double-ridge gradient double-ridge loading rectangular wave guide; a first rectangular wave guide and a second rectangular wave guide. The first double-ridge loading rectangular wave guide and the second double-ridge loading rectangular wave guide are respectively connected with two ends of the double-ridge loading rectangular wave guide that is in a 90 degree bending; the double-ridge gradient double-ridge loading rectangular wave guide is connected between the second double-ridge loading rectangular wave guide and the first rectangular wave guide; and the second rectangular wave guide is connected with an outboard curved surface window of the double-ridge loading rectangular wave guide that is in a 90 degree bending, wherein a central axis of the double-ridge loading rectangular wave guide that is in a 90 degree bending is superposed with a central axis of the first rectangular wave guide. According to the invention, broadband microwave signal energy and a band shape electronic beam can be well introduced and a sine wave guide structure can be lead out; besides, the input / output structure is simple and is easy to process and realize.

The invention discloses a dual-circularly-polarized millimeter wave reflection array antenna with independently controllable beams, which comprises a broadband circularly-polarized feed horn antenna (1) and a planar reflection array (2). The broadband circularly-polarized feed horn antenna (1) is located near the focal plane of the planar reflection array (2). The planar reflection array (2) is composed of sub-wavelength dual-circularly-polarized phase shifting elements (3) arranged periodically. Each dual-circularly-polarized phase shifting unit (3) contains four metal layers, wherein a firstlayer is a metal patch (3a), a second layer is a metal floor (3c) with two H-shaped slots (3b), a third layer is composed of two metal micro-strip transmission lines (3d) of different lengths, and afourth layer is a metal base plate (3e). The antenna can realize dual-circularly-polarized highly-directional beams, can independently control the beam directions of left-hand circularly-polarized waves and right-hand circularly-polarized waves, and has a broad application prospect in wireless communication and satellite communication.

The invention discloses a single-layered broadband random surface. The random surface comprises a dielectric substrate (2), a windmill metal patch 1 basic unit (1) and a metal floor (3), wherein the windmill metal patch 1 basic unit (1) and the metal floor (3) are respectively coated on the upper surface and lower surface of the dielectric substrate (2); the metal floor (3) is used for preventing electromagnetic wave transmission; the basic unit (1) is formed by using a single-layered double-resonance unit with a randomly distributed size, and composed of a regular square ring located in the center of the unit and a branch-containing square ring located at the periphery of the regular square ring. The random surface disclosed by the invention can be used for effectively reducing the RCS (radar cross-section) of a two-dimensional metal target body in an X waveband; the random surface is simple in manufacturing and easy to operate; the random surface has absolute advantages in comparison with previous multilayer modes, so that the random surface has extremely high application prospect in practice.

The invention discloses a broadband high-gain flat-plate Vivaldi antenna. In the antenna, a medium substrate (2) is taken as a carrier; a copper foil (1) with a horn-shaped opening is coated on one plane of the medium substrate (2); gradient anisotropic zero-refractive index materials (3) formed by a series of bending line artificial units (4) with different arm lengths (my) are arranged at the horn-shaped opening; and a plurality of the gradient anisotropic zero-refractive index materials (3) are arranged on the two sides along a direction vertical to an antenna plane to form a multi-layer gradient anisotropic material. The multi-layer gradient anisotropic material can effectively improve the E-plane directing property and the gain of an original Vivaldi antenna, has a very obvious multi-layer effect, is simple to manufacture and convenient to operate, has absolute advantages compared with a conventional improved mode, and has very high application prospect in practice.

The invention discloses a wideband Yagi aerial for half-mould substrate integrated waveguide feed, comprising a dielectric substrate which is provided with a metal coating on both sides. The structurecomprises a half-mould substrate integrated waveguide, a Yagi aerial, a micro-strip gradual-change transition wire and a 50 Ohm micro-strip output wire. The half-mould substrate integrated waveguidecomprises a metallic through hole, an upper metal coating and a lower metal coating. The Yagi aerial comprises a wave director, a cross feed source matrix of upper and lower surfaces, and parallel wires. For measuring conveniently, the micro-strip gradual-change transition wire is connected between the half-mould substrate integrated waveguide and the 50 Ohm micro-strip output wire. The half-mouldsubstrate integrated waveguide structure is used as the feeding structure of aerial, so the 180 DEG balanced line structure with a current phase difference of upper and lower metal surfaces is formedand can be directly connected to the Yagi aerial. For improving the plus, four wave directors are used to form a printed antenna structure, with wideband, high plus, low cost and low outline.

The invention discloses a quantitative correlation amplitude holographic method based on a photon sieve and belongs to the field of micro-nano holography. The implementation method comprises the following steps: obtaining two binary amplitude holograms according to a holographic reproduction image, and representing phase information in an amplitude form to improve a traditional phase retrieval GSalgorithm to generate two independent binary amplitude holograms; establishing a quantitative association relationship between the two independent binary amplitude holograms by introducing a concept of 'holographic mask' to realize the quantitative association of the binary amplitude holograms, performing evaluation and cyclic optimization by measuring a peak signal to noise ratio (SNR) to obtaina group of quantitative associated amplitude holograms corresponding to the holographic reproduction image, and generating a processing file. Two mutually associated transmission type photon sieves are prepared by using a pixel with a transparent unit coding value of 1 and a pixel with a lightproof unit coding value of 0. Visible light or near-infrared incident light irradiates on two mutually associated transmission type photon sieves, and the holographic reproduction is carried out on a Fourier surface to obtain two completely different reproduction images.

The invention discloses a scattering and wave-transmitting integrated electromagnetic coding metamaterial integrated with multiple phase regulation and control. The scattering and wave-transmitting integrated electromagnetic coding metamaterial is composed of metamaterial basic units of a multi-layer stacked structure. Each basic unit comprises a first metal layer, a first dielectric layer, a honeycomb layer, a second dielectric layer and a second metal layer which are arranged in sequence, wherein the first metal layer comprises a deformed Jerusalem cross, and the second metal layer comprisesa cross groove. Due to the special structural design, the units have anisotropism, and different reflection and transmission characteristics are shown under incidence of x and y polarized waves. According to the invention, the structure is simple, the processing is easy, the RCS reduction can be realized by using a scattering mechanism in a broadband, and a wave-transparent frequency point with high transmissivity exists in an RCS reduction band, so that the working environment of radio equipment is effectively improved.

The invention discloses a broadband directional pattern reconfigurable antenna, which comprises a substrate and a broadband coupling feed Balun, wherein the front surface of the substrate is etched with two parallel main radiating elements of the antenna, the two main radiating elements are mutually spaced, the back surface of the substrate is etched with the broadband coupling feed Balun; the two parallel and mutually-spaced main radiating elements are each provided with a pair of ''L''-shaped bending dipole radiating elements at the end parts; and the two parallel and mutually-spaced main radiating elements are each provided with a pair of straight dipole units at the end parts. The broadband directional pattern reconfigurable antenna has the advantages of being small in size, light in weight and simple in structure, having no baffle board and being wide in bandwidth, can achieve E plane and H plane pattern reconfigurability simultaneously, is suitable for fields of military and civilian radar, wireless communication and intelligent weapon guidance and the like.

The invention discloses a double-fed wind turbine generator subsynchronous oscillation suppression method of a broadband rotor additional damping, which is implemented in control of a rotor-side converter of a doubly-fed fan and used for suppressing subsynchronous oscillation of a doubly-fed wind turbine generator; the three-phase currents of a double-fed fan rotator is detected; after the rotor current is detected, Park transform is performed on the three-phase currents to form a DQ axis system; filtering is performed by using a filter, sub-synchronous frequency band components of the rotor currents are extracted in real time, and then phase compensation and proportional amplification control is performed, the virtual additional rotor damping is added to an original converter DQ-axis rotor voltage control command. A control strategy of a fan rotor-side converter is changed to perform subsynchronous oscillation suppression, broadband additional damping control is increased on the rotor-side so as to enhance the damping characteristics of a subsynchronous frequency band of the wind turbine generator, the electrical damping of the whole wind turbine generator is enhanced, the subsynchronous oscillation of the system is suppressed; and the method can avoid additional devices, and is conductive to engineering implementation.

The invention discloses a voltage controlled oscillator capable of realizing oscillation during the whole range of voltage control from zero to power voltage. The voltage controlled oscillator comprises a main biasing circuit, a secondary biasing circuit, a ring oscillator, an oscillator generating circuit of a main power supply regulating circuit and a secondary power supply regulating circuit; the secondary biasing circuit outputs secondary biasing voltage to the secondary power supply regulating circuit under the function of voltage control, the secondary power supply regulating circuit is turned on and controls the ring oscillator to generate oscillation signals; the main biasing circuit outputs main biasing voltage to the main power supply regulating circuit under the situation that the control voltage is less than voltage threshold and the main power supply regulating circuit is turned off; the main biasing circuit outputs main biasing voltage to the main power supply regulating circuit when the control voltage is more than or equal to the voltage threshold, the main power supply regulating circuit is turned on and controls the ring oscillator to generate oscillation signals. The oscillator is capable of realizing oscillation during the whole range of voltage control from zero to power voltage and is characterized by high degree of linearity and broadband.

The invention belongs to the field of antenna technology, and discloses a broadband surface wave antenna loaded based on an inhomogeneous period structure. The antenna comprises a periodical metal path array which is printed on the upper surface of a first dielectric substrate. The first dielectric substrate is arranged above a second dielectric substrate and an air medium is utilized for separating. A circular patch is printed on the upper surface of the second dielectric substrate. A metal floor is arranged on the lower surface of the second dielectric substrate. An inner conductor in a coaxial probe is connected with the center of the circular path and the center of the metal floor. Compared with a uniform period patch unit which is utilized in an existing surface wave antenna, the inhomogeneous periodical path unit is advantageous in that two adjacent resonant modes are excited simultaneously; and the bandwidth of the antenna is expanded through combining the two resonant modes. Compared with a no-air-medium structure of an existing surface wave antenna, the broadband surface wave antenna is advantages in that a feeding unit utilizes air near-coupling for supplying a relatively wide impedance bandwidth; and furthermore the broadband surface wave antenna has advantages of reducing radius of the metal floor, prolonging path of a surface wave diffraction field, and realizing a broadband characteristic.

The invention relates to the technical field of radio frequency, and discloses a tunable broadband low-noise amplifier. The tunable broadband low-noise amplifier comprises a matching network, a switched capacitor output frequency selection network and an amplifying circuit; a signal input end is connected with the matching network for noise matching; the amplifying circuit is of a common-source common-gate structure. The grid of the first transistor is connected with the matching network; the grid electrode of the second transistor is grounded after being connected with a third capacitor, thesource electrode of the first transistor is grounded after being connected with a third inductor, the drain electrode of the second transistor is grounded after being connected with a fifth inductor and a fourth capacitor, the drain electrode of the second transistor is further connected with a switched capacitor output frequency-selecting network and a fourth inductor, and the fourth inductor isconnected with a signal output end. According to the structure, the switched capacitor can be adjusted to output the frequency-selecting network, and the conversion of the working frequency is realized, so that the performance of the low-noise amplifier on each frequency band is improved, the gain and noise indexes are improved, and the receiver sensitivity is improved. The input network with thestructure has broadband characteristics, and the output network has narrowband and tunable characteristics.

The invention discloses a sierpinski fractal MIMO antenna based on time reversal, and belongs to the technical field of electronics. The antenna is provided with three ports, work frequency bands of two MIMO ports can cover common frequency bands of mobile communication GSM / WCDMA, and the work frequency band of the supplement port can cover common frequency bands of a wireless network WLAN / WiMAX. Two sierpinski fractional triangles are distributed in a short distance, the sierpinski fractional triangles each have a sub-wavelength structure and can form a near-field scatterer, and accordingly the antenna has a super-resolution characteristic on a time reversal electromagnetic environment, isolation of the ports can be naturally improved on the time reversal electromagnetic environment, and when the antenna is designed, an overall design concept is adopted, the coupling effect is considered and accordingly radiant efficiency is prevented for descending.