383 results about "Plane wave" patented technology

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

The invention aims to provide a medium-loaded ultra-wideband miniaturized double-ridged horn antenna, and belongs to the technical field of double-ridged horn antennas. A dielectric structure loaded on a horn mouth surface in the antenna comprises a dielectric lens, a dielectric flat plate and a dielectric guide section with a specific shape, and through loading of an integrated dielectric structure formed by the dielectric lens, the dielectric flat plate and the dielectric guide section, impedance mutation from a metal waveguide to a free space can be optimized, and reflection is reduced; electromagnetic waves are guided to converge, beam divergence is reduced, and the directivity and gain of a main lobe are improved; meanwhile, the wavefront of the horn mouth electromagnetic wave can be corrected to be a plane wave, phase distortion is reduced, and the far-field directivity is improved; focused electromagnetic waves are refracted, side lobes are reduced, and main lobe gain is improved. The ultra-wide-band miniaturized double-ridge horn antenna has excellent comprehensive performance of ultra wide band, miniaturization, high gain and low side lobe.

The present invention proposes a method for solving the transmission characteristics of a cellular frequency selective surface. The implementation steps include: constructing a unit geometric model of the cellular frequency selective surface; performing mesh division on the unit geometric model; calculating the direction vector of the polarized plane wave in OXYZ; calculating the incident field at the excitation port in different modes; constructing a finite element matrix equation; performing matrix element substitution on the matrix equation; and obtaining the transmission characteristics of the cellular frequency selective surface. By using two vector edges of the excitation port and transforming the three-dimensional coordinate system into a three-dimensional local coordinate system, and calculating the wave numbers of the polarized plane wave in the three axial directions of the three-dimensional local coordinate system, the present invention calculates the incident field at the excitation port in different modes, avoiding the defect in the prior art that the incident field at the excitation port cannot be calculated in a coordinate system with two vector edges of a regular hexagon as the coordinate axes by using the finite element method, and achieving high-precision solution of the transmission characteristics of the cellular frequency selective surface.

The present invention discloses a method for recording and displaying photopolymers based on a computer-generated holographic bin algorithm. S1: After a beam of light emitted by a femtosecond pulse laser is expanded and collimated, the pulse laser is focused on a photopolymer material through an objective lens, causing the refractive index of the photopolymer to change. The position of the photopolymer is controlled by controlling a translation stage to achieve three-dimensional recording of two pieces of material. S2: The complex amplitude distribution of the object is calculated through the computer-generated holographic bin algorithm and the two pieces of material are encoded. The exposure time and other parameters are controlled by a computer, and the femtosecond laser is used to write the calculated and encoded phase information diagram on the photopolymer. S3: After recording, the second beam splitter and the objective lens in front of the recording position are removed, and a plane wave is used to simultaneously irradiate the two pieces of engraved photopolymer and combine the beams to obtain a reproduced image of the three-dimensional object. The recording and display of the three-dimensional object can be achieved.

The present invention discloses a method for calculating the harmonic response of a magneto-electro-elastic structure using enhanced overlapping triangular units, which relates to the technical field of magneto-electro-elastic intelligent materials. In the process of constructing a local enhanced interpolation basis function, a composite basis function consisting of a Lagrange polynomial basis function and a plane wave basis function is used for construction; in the process of constructing a local numerical approximation, a weighted function is constructed by introducing a mid-edge node in each enhanced overlapping triangular unit, and numerical interpolation is completed under the premise of satisfying the unit decomposition characteristics. Based on the numerical interpolation, a dynamic matrix control equation of the magneto-electro-elastic structure is established, and an enhanced overlapping finite element numerical model of the solver dynamic response is obtained. After applying appropriate boundary conditions and external excitations, a high-precision prediction of the harmonic response of the magneto-electro-elastic structure can be completed.

The present application relates to the technical field of optical aspheric surface, especially points to a kind of free curved surface characterization method based on CGH lens zero position compensation detection optical path, with the detection of free curved surface as the guide, based on zero position compensation detection principle, according to ray tracing method, Snell's law, diffraction principle and equal optical path principle, using the parameters required by interferometer incident wave front as plane wave, compensator as single CGH lens zero position compensation detection system indirectly characterizes free curved surface shape, by using XY polynomial and Zernike standard phase polynomial, the mathematical description of free curved surface is realized in design stage can determine its measurement scheme, and according to the characterization method self-defined a kind of aspheric surface type, called zero position free curved surface.The free curved surface characterization method improves the degree of freedom of free curved surface shape and the feasibility of zero position compensation method, reduces the detection difficulty of free curved surface shape, realizes the function of zero position free curved surface design can be detected.

The present application relates to the technical field of ultra-short baseline direction measurement data processing, and particularly relates to a direction estimation method of a multi-element stereo hydrophone array. The method approximates sound waves as plane waves and establishes a mathematical relationship between time difference of arrival (TDOA) and a direction vector, takes TDOA as an observation value, calculates a direction vector estimation value according to a weighted least square method, then calculates the equivalent weight of the observation value according to an equivalent weight function, further replaces the original observation value weight array with an equivalent weight array, and recalculates the direction vector according to the weighted least square method, iteratively calculates the equivalent weight and the direction vector, until the difference between the direction vectors of two consecutive times is less than a manually set threshold, and the direction vector is output as the direction of the multi-element stereo hydrophone array. The present application can weaken the influence of the sound ray bending which is not considered in the direction estimation function model, and consider the influence of the array element spacing and the target direction on the direction estimation, thereby improving the accuracy and reliability of the direction estimation of the multi-element stereo hydrophone array.

This invention provides a method for rapid planar near-field measurement of large-aperture antennas, relating to the field of antenna technology. The method obtains sparse field amplitude and phase information of several sampling surfaces in the near-field radiation region of the antenna under test through large-step uniform sampling. Simultaneously, it samples a finite number of precise field amplitude and phase information points for each sampling surface and obtains the field distribution characteristics by calculating the fluctuation of the amplitude at the sampling points. Based on the sparse field amplitude and phase information and field distribution characteristics of the sampling surfaces, it uses partitioned interpolation and field distribution calibration methods to obtain the initial electric field of each sampling surface. Based on planar wave spectrum theory, iterative numerical calculations are performed on the initial electric field to recover the near-field distribution of each sampling surface. Finally, the far-field radiation characteristics of the antenna are obtained through near-field-to-far-field transformation. This invention can significantly shorten the testing time while obtaining key indicators of the antenna's far-field characteristics, including the normalized radiation pattern main lobe and first sidelobe, 3dB beamwidth, sidelobe level, and axial ratio.

The application discloses a near-field strong interference suppression method based on spherical wave deconvolution beam forming positioning, which comprises the following steps: performing fine grid division on a near-field scanning area of a linear array; performing spherical wave focusing beam forming on the near-field scanning area and two-dimensional deconvolution beam forming about distance-angle under the condition of unknown sound source position; calculating the distribution entropy characteristics of the deconvolution beam forming result in the angle dimension, and using a preset threshold to correlate the interference positioning of a target; constructing an array flow pattern matrix A of each near-field target l and generating a covariance matrix A; calculating the orthogonal complement space projection matrix of the covariance matrix A, and applying the orthogonal complement space projection matrix to the array element domain covariance matrix C to perform near-field interference suppression; using a far-field plane wave model to perform deconvolution beam forming calculation on the covariance matrix for suppressing near-field interference, so as to obtain passive detection results of the near-field strong interference suppression. The application can realize near-field interference positioning and interference suppression under the condition that the interference position is unknown.

Methods and seismic data processing apparatuses use a down-going annihilation operator to generate an image from seismic data acquired over a water-covered subsurface formation. The down-going annihilation operator is derived using a down-going wavefield and an estimated water-wave extracted from the seismic data. The down-going annihilation operator may be derived in plane-wave domain.

The invention provides a curved surface polarization torsion reflecting surface and an antenna using the same, and belongs to the technical field of antennas. The curved surface polarization torsion reflection surface comprises a curved surface dielectric plate, and a metal bottom plate and an electromagnetic metasurface which are respectively arranged on the outer side and the inner side of the curved surface dielectric plate; the electromagnetic metasurface is formed by periodically arranging a plurality of single-layer electromagnetic metasurface units. The single-layer metasurface unit with the polarization torsion function is conformal on the curved surface, so that the technical problems that a traditional multi-layer planar polarization torsion structure is complex to process, curved surface conformal is difficult, and the performance is deteriorated after conformal are solved. The reflecting surface is preferably a paraboloid, so that the incident wave polarization torsion is realized, and the spherical wave can be converted into the plane wave to improve the antenna gain. The metasurface unit keeps good cross polarization reflection performance within the wide incidence angle range of 0-40 degrees, is suitable for curved surface conformal design, can be integrally formed through 3D printing, and is easy and convenient to machine and stable in performance.

The invention particularly relates to an automatic design method of an antenna housing, which comprises the following steps: configuring a corresponding first self-defined design parameter according to a preset application scene of a target antenna housing, and generating a corresponding first self-defined parameter file based on the first self-defined design parameter; the first custom design parameters comprise an antenna housing form, a dielectric substrate performance parameter and an antenna housing structure parameter; obtaining a second user-defined performance parameter configured by the user on the graphical user interface, and generating a corresponding second user-defined parameter file; wherein the second custom performance parameter comprises any one or a combination of any more of the following parameters: an antenna housing application frequency band, a plane wave incident angle, the thickness of each layer of dielectric material, a dielectric constant and a loss angle tangent; and in response to a trigger instruction of a user, generating corresponding relation data between the wave transmissivity and the frequency and wave transmissivity data in different polarization modes according to the second custom design parameter, and displaying the relation data and the data in the image user interface.

The invention discloses an antenna regulation and control method based on collaborative design of a gradient refractive index dielectric lens and a hyperbolic reflecting surface, and belongs to the technical field of communication, and the method comprises the following steps: S1, collaborative design of the gradient refractive index dielectric lens and the hyperbolic reflecting surface: designing the gradient refractive index dielectric lens, spatial shaping is carried out on a wavefront phase by utilizing the characteristic of a non-uniform material, so that accurate regulation and control on electromagnetic waves are realized; a hyperbolic reflecting surface is designed, and spherical waves radiated by a feed source are efficiently converted into collimated plane waves by using geometric focusing characteristics of the hyperbolic reflecting surface; s2, optimizing and integrating an antenna structure; s3, data collection and preprocessing; s4, constructing and training a deep learning beam optimization algorithm; s5, applying a beam optimization algorithm and performing real-time regulation and control; according to the invention, through collaborative design and a deep learning algorithm, the technical bottleneck of a traditional antenna is broken through, the main lobe gain and the pointing precision are remarkably improved, the side lobe interference is reduced, and the antenna is suitable for scenes such as satellite communication and high-precision navigation and is compatible with various communication standards.

A finite size abnormal reflection super surface design and surface impedance optimization method based on integral equation, comprising the following steps: step 1: determining the size of the abnormal reflection surface unit of the actual project; step 2: obtaining the number of super surface units in the finite size direction through the finite size / super surface unit size, and forming a super surface array; step 3: dividing each individual super surface unit into impedance pieces of equal length in the finite size direction; step 4: further dividing each small impedance piece into sub-units of equal length in the finite size direction; step 5: simulating electromagnetic waves in the form of plane waves to 0° incidence of the super surface array, generating surface current, and the surface current will excite a scattering field; the scattering field reaches the ideal state in the target direction. The impedance surface proposed in the application can be designed for any large-angle abnormal reflection angle requirement and any target size, greatly improving its practicability in future application scenarios.

The present invention discloses a calibration device and a calibration method for acoustic measurement of surface pulsating pressure. The calibration device includes a signal generator for generating noise and a plane wave generator disposed in an anechoic chamber. The plane wave generator can convert the noise signal generated by the signal generator into a plane wave. A microphone interface for connecting a monitoring microphone is provided on the plane wave generator, so that the monitoring microphone can monitor the plane wave in the plane wave generator. The plane wave generator further includes an output port for outputting the plane wave, and a reference microphone and a measurement microphone of the surface pulsating pressure acoustic measurement device to be calibrated can monitor the plane wave in the plane wave generator through the output port. It further includes a data acquisition module for acquiring data of the monitoring microphone, the reference microphone, and the measurement microphone. The present invention can calibrate the surface pulsating pressure acoustic measurement device, thereby improving the measurement accuracy of the acoustic measurement device.

The tunable infrared selective thermal emitter based on a cylindrical structure array belongs to the field of micro-nano optoelectronic technology; it is composed of multiple tunable structural units arranged periodically. Sunlight is incident in the form of a plane wave. Each tunable structural unit includes a substrate layer, a buffer layer, and an antenna from bottom to top. The substrate layer and the buffer layer are square in shape, and the antenna is a three-layer cylindrical structure. The structure of the present invention is simple. In the atmospheric windows of 3-5μm and 8-14μm, the average emissivities are about 0.20 and 0.18 respectively, and the average emissivity in the non-atmospheric window of 5-8μm is about 0.80. Moreover, it is not affected by the polarization of the light source and has good emission effects within the incident angle range of 0°-60°. The addition of GST enables the thermal emitter to not only meet the requirements of low emissivity in the atmospheric window and radiative heat dissipation in the non-atmospheric window, but also tune the infrared emissivity spectrum to achieve switching between the infrared "stealth" and "non-stealth" states.