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483 results about "Plane wave" patented technology

In physics, a plane wave is a special case of wave or field: a physical quantity whose value, at any moment, is constant over any plane that is perpendicular to a fixed direction in space.

Channel modeling method and device suitable for satellite-ground communication

The invention provides a channel modeling method and device suitable for satellite-ground communication, and the method comprises the steps: generating a satellite motion track, and setting ground environment parameters and simulation parameters; converting the satellite motion trail from a global coordinate system to a local coordinate system; acquiring a satellite position from the converted satellite motion trail, and performing ray tracing calculation based on plane wave hypothesis to obtain all effective ray paths between the satellite position and the position of a ground receiver; for each effective ray path, calculating large-scale fading caused by a meteorological environment and small-scale fading caused by ground end multipath propagation and multi-end movement; and a channel model is generated by combining large-scale fading and small-scale fading. According to the method, large-scale fading caused by the meteorological environment is modeled, the influence of meteorological attenuation on the multipath receiving power is considered, small-scale fading caused by multipath propagation and multi-end movement at the ground end is modeled, and the modeling accuracy is improved.
Owner:PURPLE MOUNTAIN LAB

Method for realizing acoustic vortex tunneling transmission on metasurface based on topology

The invention provides an acoustic vortex tunneling transmission method based on topology pairing metasurfaces, and the method comprises the steps: respectively arranging an absorption type metasurface and an emission type metasurface which have opposite topological charges at an inlet and an outlet of a tunneling channel, forming a pair of topology pair TPMs structures, and forming a vortex tunneling system together with a sub-wavelength channel; mode conversion between vortex waves and plane waves is achieved through multi-period fan-shaped grooves etched in the angular direction and the radial direction, and the transmission efficiency is enhanced through Fabry-Perot resonance in a sub-wavelength channel. When the length of the tunneling channel meets specific conditions, periodical adjustment of transmissivity and perfect tunneling can be achieved, and the tunneling structure has high OAM mode coupling and transmission efficiency while guaranteeing the compact structure and low material cost. The metasurface designed by the invention supports diversified acoustic vortex tunneling transmission along a straight line and a curve, and shows excellent flexibility and stability.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Light-weight paper-based reflecting lens for electromagnetic wave beam modulation and planar reflecting antenna of light-weight paper-based reflecting lens

The invention discloses a light paper-based reflection lens for electromagnetic wave beam modulation and a planar reflection antenna thereof, and belongs to the technical field of antennas. The reflecting lens comprises a paper-based main body, the paper base main body is formed by forming a hole structure which is surrounded by a sheet-shaped paper base and is periodically arranged at intervals, and the paper base main body is provided with an upper surface and a lower surface which are opposite to each other and are respectively an electromagnetic wave control surface and a reflection plane; film-shaped symbol units made of metal materials are distributed and attached to the sheet-shaped paper base; the planar reflection antenna further comprises a feed source. The feed source is close to and inversely installed on the control surface, and the feed source reciprocates along the track of the control surface. An electromagnetic wave reflecting plate is arranged on the surface of the reflecting plane. The feed source can be placed at any position of the control surface, and electromagnetic waves emitted by the feed source at any position can be spread out of the reflection lens in a plane wave form after passing through the plane reflection antenna. Moreover, the bandwidth of wide-angle scanning realized by the plane reflecting antenna can reach 80%, which is far wider than that of the traditional reflecting surface antenna.
Owner:SOUTH CHINA UNIV OF TECH

Diffracted wave separation method and device under non-uniform space-time sampling

The invention provides a diffracted wave separation method and device under non-uniform space-time sampling, and relates to the technical field of seismic prospecting, the method comprises the following steps: obtaining common offset seismic data of a target area, the common offset seismic data comprising fluctuation signals of a plurality of sampling points, the position intervals among the sampling points of different seismic traces are non-uniform, and / or the time intervals among different sampling points of the same seismic trace are non-uniform; calculating the plane wave slope of each sampling point of the common offset seismic data through a finite difference method to obtain plane wave slope data; determining a reflected wave travel time curve of each sampling point according to the plane wave slope data; and diffracted wave separation of the common offset seismic data is carried out according to the reflected wave travel time curve of each sampling point. According to the method, accurate diffracted wave separation under non-uniform space-time sampling is realized, and the seismic data analysis accuracy is improved.
Owner:CHINA UNIV OF MINING & TECH (BEIJING)

Broadband 4T4R automobile radar antenna

A broadband 4T4R automobile radar antenna disclosed by the present invention comprises an upper-layer radiation plate and a lower-layer feed plate, the upper-layer radiation plate is provided with a plurality of horn mouths and a plurality of EBG choke grooves, the horn mouths and the EBG choke grooves are distributed at intervals in a staggered manner, each horn mouth is internally provided with a plurality of radiation slots at unequal intervals, and the upper-layer radiation plate is provided with a plurality of feed slots. A waveguide feed port is arranged on the lower surface of the lower layer feed panel; compared with the prior art, in order to ensure the antenna gain, the choke design in the EBG form is adopted between the antenna units, the transmission of surface waves is effectively restrained, and the isolation degree between the antenna units is improved; the horizontal plane realizes a good gain effect by accurately optimizing taper pin distribution of the slot array and amplitude-phase excitation of the feed network, and has better sidelobe envelope directional diagram characteristics; and the width of the lobe on the horizontal plane is adjusted by adjusting the inclination angle of the horn mouth, so that the width reaches 63 + / -3 degrees, and the gain effect is effectively improved.
Owner:SHENZHEN HUILIANDA TECH CO LTD

Target trajectory tracking method and product based on azimuth statistical analysis and prediction

The invention discloses a target trajectory tracking method and product based on azimuth statistical analysis and prediction, and the method comprises the steps: converting a horizontal array manifold vector according to a set interval, carrying out the array signal processing of the array manifold vector at each angle according to a set scanning interval, and obtaining the beam width at the angle; performing spatial spectrum synthesis on the horizontal array receiving data according to a plane wave array signal processing method to obtain a horizontal array data synthesis azimuth spectrum; presetting an initial azimuth angle of a to-be-tracked target, and solving a target azimuth angle at the current moment in combination with a target operation attribute corresponding to the azimuth angle, an array azimuth estimation error and a beam width; within the statistical time, adopting a least square method to predict a target azimuth angle, and adopting a target azimuth angle track compensation value to compensate a target azimuth angle prediction value; the target azimuth angle at the current moment is extracted according to the target azimuth angle predicted value, and then continuous and stable tracking of the target azimuth trajectory is completed.
Owner:INST OF ACOUSTICS CHINESE ACAD OF SCI

Reconfigurable acoustical holography modulation method and device based on crystalline polymer

The invention discloses a reconfigurable acoustical holography modulation method and device based on a crystalline polymer. The programmable acoustical holography device is composed of a single-layer photoresponse crystalline polymerization flat plate, is switched between two phases when the temperature irradiated by laser changes, has a crystalline state and a non-crystalline state, and reversibly changes along with the temperature. Space sound field modulation can be realized by spatially arranging the coding units, the crystalline polymer flat plate subjected to laser patterning phase change is recovered to the previous crystalline state after being cooled, the patterned coding acoustical holography disappears, and new phase acoustical holography is written in, so that a new sound field modulation function is realized. According to the programmable phase acoustical holography device based on the crystalline polymer, the incident plane wave of the probe can be modulated into any three-dimensional complex sound field, and the programmable phase acoustical holography device is of a complete plane type, is matched with underwater acoustic impedance, and is high in acoustic energy coupling efficiency, compact in structure, easy to prepare and low in price.
Owner:ZHEJIANG UNIV

Design method for realizing virtual polarization element

The invention discloses a design method for realizing a virtual polarization element, relates to the field of optical device design, and aims to solve the problems of large size, difficulty in integration and limited regulation and control capability of a traditional polarization device. According to the method, a virtual polarization function (including a Jones matrix and an additional phase) is preset on a target plane, a plane wave weighting factor is solved through high-dimensional Fourier transform, and source plane light field distribution is generated through superposition. The metasurface is used as a platform, and accurate mapping from a source plane Jones matrix to a device structure is realized by adjusting geometric parameters of a nanostructure and combining a double-matrix holography. According to the design scheme, a polarization state with controllable spatial distribution can be generated as required in a two-dimensional plane at any propagation distance, and additional phase information can be flexibly superposed, so that the flexibility, precision and integration capability of light field regulation and control are remarkably improved, and technical support is provided for applications such as new-generation lens-free imaging, polarization coding communication, light field synthesis and the like.
Owner:SHENZHEN RES INST OF XIAMEN UNIV +1

Three-dimensional ultrasonic imaging method and system, computer equipment and computer program product

The invention is suitable for the technical field of ultrasonic imaging, and provides a three-dimensional ultrasonic imaging method and system, computer equipment and a computer program product, and the method comprises the steps: transmitting a multi-angle composite plane wave sequence to a target region through a one-dimensional ultrasonic array with the frequency gradual change characteristic in the elevation direction, and receiving a reflected echo signal sequence, generating a target gray-scale image sequence corresponding to the echo signal sequence, acquiring coordinates of each ultrasonic contrast agent microbubble in each frame of gray-scale image, generating a two-dimensional coordinate set, calculating the axial half-peak full width of a point spread function region of each ultrasonic contrast agent microbubble, and calculating the axial half-peak full width of the point spread function region of each ultrasonic contrast agent microbubble; determining the coordinate of each ultrasonic contrast agent microbubble in the elevation angle direction based on the axial half-peak full width, generating an elevation angle coordinate set, and generating a three-dimensional contrast image of the target area based on the two-dimensional coordinate set and the elevation angle coordinate set. According to the method provided by the invention, the problem that three-dimensional ultrasonic imaging is limited by the surface ultrasonic array can be solved, and low-cost, simple and efficient three-dimensional ultrasonic imaging based on the one-dimensional ultrasonic array is realized.
Owner:SOUTHERN UNIVERSITY OF SCIENCE AND TECHNOLOGY +1

On-line automatic bar flaw detection method and device based on full-focusing phased array technology

The invention relates to the technical field of full-focusing phased arrays, and discloses an on-line automatic bar flaw detection method and device based on a full-focusing phased array technology. According to the method, after water immersion type coupling is carried out, array elements of a concave array phased array probe are excited in a plane wave emission mode, multi-angle acoustic beams are formed, and full-matrix echo data are captured; for transverse wave detection, the sound field uniformity is improved by adopting a grouped alternate emission mechanism. Full-domain dynamic focusing is realized through coherent superposition processing, and real-time alarm and mark spraying are carried out on standard exceeding defects in combination with encoder data. The device comprises an off-line automatic calibrator, a conveying roller way, a steel splitting instrument platform, a pinch roll system, a lifting transverse moving platform, an ultrasonic detection host, a mark spraying system, a water circulation system and a PLC system, and efficient and accurate on-line bar flaw detection is achieved.
Owner:JIANGSU JINYU INTELLIGENT DETECTION SYST CO LTD

Transmission-type metasurface loading antenna and transmission-type metasurface plate

[Problem] To provide a transmission-type metasurface plate and a variable directivity antenna that make it possible to reduce loss in a transmission line and reduce costs by standardizing components compared to the prior art. [Solution] This transmission-type metasurface loading antenna comprises a transmission-type metasurface plate and an antenna section arranged parallel to the transmission-type metasurface plate. The transmission-type metasurface plate has a plurality of transmission elements, and near-plane waves incident from one surface are converted in one plane by the transmission-type metasurface plate into directional electromagnetic waves having directivity in a predetermined direction. The transmission elements transmit the incident near-plane waves with a predetermined phase difference. The transmission-type metasurface plate has transmission elements with different predetermined phase differences. The antenna section is a plane wave antenna that emits near-plane waves.
Owner:DENKI KOGYO CO LTD

Ultrafast three-dimensional wave number domain imaging method based on row-column addressing ultrasonic array

The invention discloses an ultrafast three-dimensional wave number domain imaging method based on a row-column addressing ultrasonic array, which realizes ultrafast three-dimensional ultrasonic volume imaging by combining wave number domain image reconstruction based on row-column addressing (RCA) ultrasonic array probe data acquisition. According to the method, the three-dimensional volume imaging capability and channel number advantages of an RCA ultrasonic array probe and fewer emission times of plane wave imaging (PWI) are utilized, so that the volume acquisition rate is increased, and the data volume is reduced; according to the method, wave number domain image reconstruction is executed, rapid reconstruction of three-dimensional volume data can be realized by utilizing the calculation efficiency of fast Fourier transform, and the three-dimensional imaging requirements of high resolution and high frame rate are met. Compared with a time domain delay superposition algorithm, the method has remarkable technical advantages and is expected to be popularized and applied to medical and industrial detection scenes needing real-time three-dimensional volume imaging.
Owner:ZHEJIANG UNIV

Magnetic nanoparticle concentration distribution inversion method and related device

The invention discloses a magnetic nanoparticle concentration distribution inversion method and a related device, and relates to the technical field of biomedical engineering.The method comprises the steps that firstly, magnetic nanoparticles in biological tissue are excited through an external magnetic field to generate infinitesimal displacement; and then ultrasonic equipment is adopted to collect ultrasonic ultrafast plane wave imaging data and carry out axial vibration displacement detection, axial vibration displacement actual measurement data and corresponding discrete space and time coordinates are input into the inversion model for iterative inversion, and a magnetic nanoparticle concentration distribution inversion result is obtained. A loss function of the inversion model includes a data-driven loss item and a physical information-driven loss item (based on a Navie equation). Compared with the prior art, the method has the advantages that the physical information neural network is introduced, control equations such as a nano-dimension equation and the like are encoded to the full-connection neural network, physical equations do not need to be excessively simplified, complex and time-consuming modeling for an experimental environment is not needed to obtain simulation data, and higher accuracy and stability are achieved.
Owner:SHENZHEN UNIV

Sparse array large plane wave generator for OTA test

According to the sparse array large plane wave generator for the OTA test, the amplitude and the phase of each antenna unit in an array are reasonably regulated and controlled, and large plane waves are synthesized in a short distance. The generator comprises a vector network analyzer, a signal generator, a channel simulator, a power amplifier, N paths of amplitude-phase adjustable feed networks, an antenna unit and a sparse array antenna. The signal generator generates an analog communication test signal, the analog communication test signal enters the power amplifier through a target channel created by the channel simulator, the signal is transmitted to the sparse array antenna through the N paths of amplitude-phase adjustable feed networks, and a large plane wave is formed on a radiation aperture of the sparse array antenna. Excitation amplitude and phase distribution of the sparse array antenna are calculated through a constraint optimization algorithm, and a saddle-shaped beam can be formed in a far-field area, which is equivalent to forming a plane wave at a radiation aperture of the sparse array antenna. Amplitude and phase distribution of the sparse array antenna is realized by adopting an amplitude and phase adjustable feed network.
Owner:NANJING UNIV OF INFORMATION SCI & TECH

Base station antenna and base station

The embodiment of the invention provides a base station antenna and a base station. The base station antenna comprises a first antenna array, a metasurface lens and a second antenna array, the metasurface lens is located between the first radiator of the radiation unit of the first antenna array and the second antenna array, and is used for reflecting a radiation signal of the first antenna array and carrying out wavefront phase regulation and transmission on the radiation signal of the second antenna array. Therefore, the radiation signal of the second antenna array penetrating through the metasurface lens is approximately focused into a plane wave. The base station comprises the base station antenna. According to the scheme, a common-caliber array antenna can be realized, the defects of mutual shielding of antennas and mutual interference of antenna performance are avoided, the problem of structural interference can be avoided, and the antenna gain can be improved.
Owner:HUAWEI TECH CO LTD

System for measuring performance of equipment under test, and method therefor

Disclosed are a system and a method for a high-speed performance measurement. The system includes: a fixing part; a positioner for controlling the rotation of the equipment by controlling the fixing part; a measurement probe; a curved reflective plate for reflecting, in the direction of the measurement probe, an electromagnetic wave radiated by the equipment and transforming the spherical wave of the measurement probe into a plane wave at the position where the equipment is provided; an arc structure including an arc arranged to be adjacent to the fixing part; a probe set including near-filed probes arranged to be spaced predetermined intervals apart from each other on the inner side of the arc; and a control unit, which receives, through a signal analyzer, signal data corresponding to an input signal from some of near-filed probes and the measurement probe.
Owner:REPUBLIC OF KOREADIRECTOR GENERAL NAT RADIO RES AGENCY

Balun-integrated full-wave oscillator radiation unit

The utility model discloses a balun-integrated full-wave oscillator radiation unit, and aims to solve the problems that a low-frequency bowl-shaped oscillator and a high-frequency die-cast half-wave oscillator are used in the conventional high-low frequency nesting scheme, so that the requirements of miniaturization and light weight of an antenna are difficult to meet, the processing cost is extremely high, and the cost is low. And meanwhile, the high-frequency oscillator is arranged in the bowl-shaped oscillator, so that the horizontal plane wave width deformation of the high-frequency oscillator is caused, the gain is influenced, and the market demand cannot be met. The Balun-integrated full-wave oscillator radiation unit comprises a fixed support and a PCB radiation plate installed on the fixed support. The structure of the full-wave oscillator is relatively simple, assembly can be completed only by installing the single-balun integrated feed sheet in the fixing support and welding and fixing the single-balun integrated feed sheet and the PCB radiation plate, miniaturization design can be achieved through the microstrip technology, the printed circuit technology and the like due to the fact that single-face embedded coupling is adopted, the requirement of miniaturization equipment is met, machining is easy, and cost is low. The production efficiency can be greatly improved, and the production cost is reduced.
Owner:DONGGUAN YUNTONG COMM TECH CO LTD

Fourier finite difference deconvolution imaging method based on inclination angle adaptive noise suppression

The invention discloses a Fourier finite difference deconvolution imaging method based on inclination angle adaptive noise suppression, and relates to the technical field of geophysical exploration of petroleum. The method specifically comprises the following steps: designing a scattering point speed model to solve a partial point spread function of an underground space; solving a partial point spread function by a speed disturbance method; solving point spread functions of all positions of the underground space by carrying out Gaussian filtering technology and inverse distance weighted interpolation on part of the point spread functions; using a plane wave destruction method to solve the inclination angle attribute of the work area, and constructing an inclination angle self-adaptive diagonal diffusion Fourier finite difference migration method based on the inclination angle attribute to solve a high-quality initial image suitable for an inversion system; and performing multi-dimensional deconvolution in the wave number domain to obtain a final migration imaging result. According to the method, the point spread function is successfully introduced into Fourier finite difference imaging, and the resolution and deep amplitude of a conventional Fourier finite difference imaging method can be effectively improved.
Owner:CHINA UNIV OF PETROLEUM (EAST CHINA)

Short-wave channel modeling method and system based on signal wavefront recovery

The invention belongs to the technical field of short-wave communication channel modeling, and discloses a short-wave channel modeling method and system based on signal wavefront recovery, and the method comprises the steps: projecting standard plane waves to an antenna array from different angles through a cooperative target radiation source, collecting antenna array signals in different directions under the condition of no disturbance, and storing the signals as calibration data; calculating the time delay of each antenna before receiving the wavefront relative to the center of the antenna array, calculating the relative time delay of the time delay and the calibration data, and multiplying the relative time delay by the wavelength to realize the time domain-space domain conversion of wavefront distortion to obtain wavefront slope distribution; and calculating the size of a Zernike polynomial coefficient of each order based on wavefront slope distribution, analyzing specific components of aberration contained in signal wavefront, and performing wavefront fitting reconstruction so as to complete short-wave channel modeling. According to the method, the Zernike polynomial is adopted to fit the wavefront disturbance quantity, the influence of the ionized layer on the wavefront of the short-wave signal is quantified in real time, and a high-precision channel model is constructed.
Owner:Chinese People's Liberation Army Cyberspace Force Information Engineering University

Self-adaptive electromagnetic radiation suppression method for equipment in high-intensity radiation field

The invention discloses a self-adaptive electromagnetic radiation suppression method for equipment in a high-intensity radiation field. The method comprises the following specific steps: establishing an electronic equipment model under external plane wave irradiation; plane wave intensity is set, and field intensity distribution of an inner cavity of the electronic equipment model is obtained; determining shielding electromagnetic effect weak points according to the field intensity distribution of the inner cavity of the electronic equipment model; establishing an energy selection surface structure comprising a plurality of slot resonance patches arranged in an array; the energy selective surface structure is arranged on the surface where the shielding electromagnetic effect weak point is located, and an energy selective surface protection structure model is established; and comparing the field intensity at the shielding electromagnetic effect weak point in the energy selective surface protection structure model with a protection requirement, and judging whether the energy selective surface structure meets the protection requirement or not.
Owner:SHANGHAI RADIO EQUIP RES INST

Method and device for observing internal structure of cavitation bubble group based on plane wave ultrasonic imaging

The invention discloses a cavitation bubble group internal structure observation method and device based on plane waves in the technical field of cloud bubble measurement, and the method comprises the steps: carrying out a hydrofoil experiment in a water tank, and generating to-be-observed cloud bubbles; adjusting the ultrasonic imaging probe array through computer programming, and adjusting time delays of different array elements to generate a plurality of plane waves with different deflection angles; collecting plane wave echoes received by each array element, and storing echo data corresponding to each deflection angle; coherent superposition is carried out on image data obtained at different deflection angles, the contrast ratio and the signal-to-noise ratio of imaging are improved, and the effect equivalent to focusing imaging is obtained.
Owner:INST OF MECHANICS CHINESE ACAD OF SCI

Large plane wave generator based on periodic rectangular reflector antenna array

The invention provides a large plane wave generator based on a periodic rectangular reflector antenna array. The large plane wave generator comprises the periodic rectangular reflector antenna array, a rectangular reflector antenna array mounting bracket, N paths of equipower distribution networks, N amplitude-stable and phase-stable cables and a microwave signal source, the periodic rectangular reflector antenna array is vertically mounted on the rectangular reflector antenna array mounting bracket and is connected with the N amplitude-stabilized and phase-stabilized cables, the N amplitude-stabilized and phase-stabilized cables are connected with the N paths of equipower distribution networks, and the N paths of equipower distribution networks are connected with the microwave signal source. By optimizing the amplitude and phase distribution of the feed source array antenna, the equal electric field intensity and phase on the radiation aperture are realized, so that quasi-plane waves are formed on the radiation aperture of the rectangular reflector antenna unit. And the N rectangular reflector antenna units are periodically arranged, so that a large plane wave is formed on the radiation aperture of the periodic rectangular reflector antenna array.
Owner:NANJING UNIV OF INFORMATION SCI & TECH

PML-coupled three-dimensional magnetotelluric anisotropy parallel finite element forward modeling method

The invention relates to a PML-coupled three-dimensional magnetotelluric anisotropy parallel finite element forward modeling method. The method comprises the following steps: according to a continuity condition of an electromagnetic field and a dispersion relation of a plane wave in TE and TM modes, determining a non-reflection condition which needs to be met by a PML; determining a parameter form of the PML meeting stable absorption performance by utilizing a relationship between an incident field and a transmission field in the lossy medium; constructing an improved wide-frequency-band PML parameter tensor according to a non-reflection condition, a parameter form meeting stable absorption performance and preset characteristic parameters; and realizing finite element forward modeling under a preset multi-level parallel architecture by using the improved wide-frequency-band PML parameter tensor to obtain a finite element forward modeling result. The method is accurate, efficient and wide in application range.
Owner:NAT UNIV OF DEFENSE TECH

Multi-beam switching antenna applied to wind finding radar and working method of multi-beam switching antenna

The invention relates to a multi-beam switching antenna applied to a wind finding radar and a working method of the multi-beam switching antenna. The antenna comprises a connecting device, a feed device and a lens device, the connecting device is a subminiature push-in connector, the input end of the connecting device is connected with the wind finding radar, and the output end of the connecting device is connected with the feed device; the feed device comprises a GCPW-SIW conversion structure and a feed source antenna. Wherein the feed source antennas are sixteen antipodal Vivaldi antennas and are used for radiating spherical waves to the lens device; the lens device is a metasurface lens, and the feed device and the lens device are arranged in an offset-focus mode. Therefore, phase compensation is carried out on spherical waves radiated by a feed device located at the focus of the lens, and the spherical waves are converted into plane waves of the emergent surface of the lens. Compared with the prior art, the method has the advantages that the actual application requirement of a wind measurement radar system is met, and accurate wind field measurement and data acquisition are achieved.
Owner:SHANGHAI UNIV

Rapid fault diagnosis method for programmable metasurface based on orthogonal coding space-time modulation

The invention discloses a programmable metasurface fault rapid diagnosis method based on orthogonal coding space-time modulation. The method comprises the following steps: step 1, applying independent orthogonal coding space-time modulation to each metasurface unit on a programmable metasurface to be diagnosed by adopting a time-varying signal based on orthogonal coding; 2, irradiating the programmable metasurface to be diagnosed by using a single-frequency plane wave; 3, receiving a reflection signal of the programmable metasurface to be diagnosed, and recovering each orthogonal coding channel energy from the reflection signal; step 4, according to the magnitude of the recovered orthogonal coding channel energy, determining a malfunctioning metasurface unit; when a certain unit breaks down, preset orthogonal coding modulation cannot be normally executed, so that a corresponding coding channel in a transmitting signal is lost, and therefore whether the unit corresponding to each coding channel breaks down or not can be judged by recovering energy distribution of each coding channel in a receiving signal, and accurate and efficient fault diagnosis is achieved.
Owner:SOUTHEAST UNIV

Surface acoustic wave holographic metamaterial and design method thereof

The invention discloses a surface acoustic wave holographic metamaterial and a design method thereof. According to the surface acoustic wave holographic metamaterial design method based on the direct search method, stepped design of the resin plate is achieved based on the photocuring 3D printing technology, the phase is changed by changing the propagation distance of sound waves in different materials, and patterned focusing of a target plane is well achieved; the reverse design of the metasurface unit is carried out by adopting a direct search method, on-demand customization can be realized, the regulation and control mode of the designed acoustic metasurface is flexible, and a new scheme is provided for the design of the acoustic metasurface under the conditions of high frequency and excitation sound field non-plane waves; the reverse independent design method provided by the invention can promote the practical application of the holographic metasurface under the conditions of high frequency and excitation sound field non-plane waves, and has important application value in the engineering fields of acoustic particle manipulation, biological cell manipulation and the like.
Owner:PEKING UNIV

Shot gather seismic diffracted wave separation method and device

The invention provides a shot gather seismic diffracted wave separation method and device, and relates to the technical field of seismic exploration, and the method comprises the steps: obtaining two-dimensional single-shot seismic data of a designated geographic region; processing the two-dimensional single-shot seismic data by using a plane wave method to obtain a space coordinate of a virtual seismic source point; based on the two-dimensional single-shot seismic data and the space coordinates of the virtual seismic source point, seismic data and a target reflected wave extraction function in a virtual seismic source space are determined; the target reflected wave extraction function is a continuous function; based on the space coordinates of the virtual seismic source point, the seismic data in the virtual seismic source space and the target reflected wave extraction function, target reflected wave field data are determined; target reflection wave field data are removed from the two-dimensional single-shot seismic data, and diffracted wave field data are obtained. The application of the target reflected wave extraction function effectively avoids the loss of the diffracted wave and the residue of the reflected wave in the separation process, so that the technical problem of poor diffracted wave separation effect in the existing diffracted wave separation method is effectively relieved.
Owner:SHENHUA MENGXI COAL CHEM CO LTD +2

Electromagnetic source positioning method and system based on generalized cross-correlation

The invention relates to the technical field of signal processing, in particular to an electromagnetic source positioning method and system based on generalized cross-correlation. According to the invention, four electromagnetic probes are uniformly arranged on the unmanned aerial vehicle to collect electromagnetic signals of target equipment, and a generalized cross-correlation function is used to calculate the signal arrival time difference between the probes. And performing abnormal value elimination and optimization processing on the time difference by adopting a statistical analysis method, and calculating an azimuth angle and an elevation angle of the electromagnetic wave in combination with a plane wave hypothesis. The included angle between the orientation and the magnetic north direction is measured through a magnetometer of the unmanned aerial vehicle, and the azimuth angle is converted into an absolute direction reference. By using a two-point positioning method, data are collected at different positions and equations are established to solve three-dimensional space coordinates of the electromagnetic source. According to the method, the multi-source data acquisition and fusion technology is combined with the generalized cross-correlation and abnormal value processing algorithm, the multi-path effect and the measurement error in the complex electromagnetic environment are effectively overcome, and an efficient and reliable positioning scheme is provided for power equipment fault diagnosis.
Owner:ELECTRIC POWER RES INST OF GUANGXI POWER GRID CO LTD

Ultrasonic plane wave inverse problem imaging optimization method and system and ultrasonic imaging device

The invention provides an ultrasonic plane wave inverse problem imaging optimization method and system and an ultrasonic imaging device, and belongs to the technical field of ultrasonic imaging, and the method comprises the steps: constructing a space coordinate system of an image in ultrasonic plane wave imaging; constructing a sampling matrix according to the space coordinate system of the image and the parameters of the transmitted ultrasonic plane waves, and weighting in combination with the directivity of the transducer element and the geometric information of the image to keep sparsity; based on the weighted sampling matrix, constructing a low-rank sparse optimization model of an ultrasonic plane wave inverse problem; and carrying out beam forming updating, nuclear norm updating and sparse item and Lagrange item updating on the low-rank sparse optimization model, and carrying out envelope detection, logarithm compression and gray mapping to obtain a final optimized ultrasonic image. According to the method, the advantage of high frame rate of plane wave imaging is fully utilized, spot textures are reserved, the imaging speed is high, meanwhile, the resolution ratio and the contrast ratio of the ultrasonic image are improved, and the imaging quality is improved.
Owner:BEIJING JINGSHENG YANMING TECHNOLOGY CO LTD

Ultrathin dual-polarized lens antenna based on double-layer Huygens metasurface

The invention discloses an ultrathin dual-polarized lens antenna based on a double-layer Huygens metasurface, and relates to the technical field of plane transmission array antennas. The ultrathin dual-polarized lens antenna based on the double-layer Huygens metasurface is provided with a horn antenna feed source module and a double-layer Huygens metasurface module. The double-layer Huygens metasurface module is composed of a medium supporting layer in the middle and metal patch layers of which the top layer and the bottom layer are identical in structure. The unit grids of the double-layer Huygens metasurface module are arranged according to hyperbolic phase distribution to form a super-lens function, and quasi-spherical waves emitted by the horn antenna feed source module are converted into plane waves emitted in a single direction, so that the directivity and radiation gain of electromagnetic waves are improved. The antenna has the advantages of dual polarization response, ultra-thin thickness smaller than one tenth of wavelength, easy integration, high radiation gain and high aperture efficiency, and can be widely applied to the fields of millimeter wave communication systems, wireless power transmission and the like.
Owner:XIAMEN UNIV