9 results about "Surface impedance" patented technology

The invention relates to the technical field of reinforcement corrosion detection, in particular to a reinforcement corrosion nondestructive testing method integrating ultrasonic and electrochemical signals, and the method comprises the following steps: calculating an environmental interference coefficient and an environmental influence evaluation value through an environmental noise signal and concrete surface impedance, and constructing an initial evaluation model; collecting and processing ultrasonic and electrochemical signals in real time to obtain characteristic parameters, and calculating an initial corrosion risk coefficient through an initial evaluation model; generating a comprehensive decision coefficient in combination with the environmental influence evaluation value, determining a feature weight distribution strategy, and generating a fusion diagnosis index; adaptively adjusting the detection point grid spacing according to the fusion diagnosis index; the diagnosis reliability is verified through the time-space consistency coefficient of the ultrasonic waves and the electrochemical active region, and a fusion diagnosis deviation value is calculated; and carrying out collaborative optimization on the detection period and the evaluation model based on the cumulative fusion diagnosis deviation value. According to the invention, the problem that a single detection means is insufficient in precision and cannot be adaptively adjusted in a complex environment is solved.

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.

This invention discloses a design method, system, device, and medium for an ultra-low profile, high-aperture efficiency transmission array antenna. The method includes: simulating tensor impedance metasurface elements and obtaining the maximum equivalent scalar surface impedance corresponding to different structural parameters; establishing an impedance-structure model; designing the impedance distribution of the tensor impedance metasurface elements; obtaining the structural parameters of the tensor impedance metasurface elements through the impedance-structure model and designing a tensor impedance metasurface; simulating transmission metasurface planar elements and obtaining the transmission coefficient phase corresponding to different structural parameters of the transmission metasurface elements; establishing a phase-structure model; obtaining the structural parameters of the transmission metasurface elements under the target aperture field phase through the phase-structure model and designing a transmission metasurface plane; and designing an ultra-low profile, high-aperture efficiency transmission array antenna based on the designed tensor impedance metasurface and transmission metasurface plane. This invention significantly improves design freedom and facilitates meeting more beamforming and radiation direction design requirements.

Method for determining a sound field in an enclosed space or at a target position within the enclosed space, the method has the following steps: performing an acoustic measurement at at least one measurement position within the enclosed space or at a single one measurement position within the enclosed space to obtain an interim value set; estimating a surface impedance as first parameter describing the enclosed space based on the interim value set; determining a model of the enclosed space based on the first parameter; and estimating a sound field throughout the enclosed space based on the model of the enclosed space, the sound field describing a sound characteristic for a plurality of positions within the enclosed space.

The invention discloses a conformal holographic metasurface antenna based on a double-layer cross embedded tensor unit, and aims to solve the problem of low surface wave-leaky wave conversion efficiency caused by inherent restriction of surface impedance modulation depth M and average impedance amplitude X of a traditional single-layer holographic metasurface antenna. An upper-layer and lower-layer cross-shaped groove patch array cross embedded topological structure is adopted, the vertical projection of a lower-layer unit is embedded into a gap region of an upper-layer unit, and the surface impedance dynamic modulation range is expanded under the sub-wavelength unit size by enhancing interlayer coupling, so that the leakage constant alpha is improved. On the basis of a holographic interference principle, surface impedance tensor modulation is realized by regulating and controlling geometric parameters of a unit, and a linearly polarized surface wave excited by a central feed source is efficiently converted into a right-handed circular polarization (RHCP) leakage wave beam with a specific angle at a frequency band of 26 GHz; in combination with a conformal mapping algorithm, the method is adaptive to a cylindrical surface with a curvature radius rho of 20-60mm, and has aperture efficiency gt; 39%, and the axial ratio is lt; 3dB, and the structure is compact.

The application discloses a kind of high-efficiency measurement high-temperature superconducting film microwave surface impedance device and method, belong to electronics technical field, device includes test probe, calibration probe, metal plate and sealed cavity, the open type bottom end surface of test probe is test plane, calibration probe and the structure of test probe are completely same, and the mirror image symmetry of two about test plane;The microwave surface resistance of metal plate is known;By with the calibration probe, metal plate or the detachable measured HTS film being placed in test plane, and being covered with sealed cavity, the working temperature of the measured HTS film is placed respectively under no-load quality factor and resonance frequency test, and the R S And X S Of the measured HTS film is obtained by calculation.The application can simultaneously measure the microwave surface impedance of the front and back of the measured HTS film, greatly improve the testing efficiency while ensuring the accuracy of the test results, suitable for mass industrial testing of HTS film, and suitable for widely used 2-inch and above size HTS film.

The present disclosure relates to a surface impedance recognition method and recognition device based on flexible piezoelectric sensing technology. The method comprises the following steps: fixing an impedance recognition system to a surface to be measured, the impedance recognition system comprising an electrode, an electrostrictive module connected to the electrode, an insulating layer located below the electrostrictive module, a sensor module located below the insulating layer, and a hard material located above the electrostrictive module; energizing the electrostrictive module to cause the electrostrictive module to deform, the insulating layer transmitting the load caused by the deformation of the electrostrictive module to the sensor module, and the load being further transmitted to the surface to be measured, causing the output of the sensor module to differ in electrical signal; and measuring the electrical signal difference by an electrical device connected to the upper and lower electrodes of the sensor module, and recognizing the impedance of the surface to be measured according to the electrical signal difference.

The application provides a 2-bit coding metasurface for simultaneously regulating spatial waves and surface waves, which comprises, from bottom to top, a metal bottom plate, a dielectric substrate and a metal patch layer; the metal patch layer is provided with periodically arranged metal patterns; the metal patch layer comprises a metasurface unit and a feeding microstrip line; the feeding microstrip line is periodically arranged along two sides of the metasurface unit; the metasurface unit comprises a transverse unit and a longitudinal unit; the transverse unit is composed of a plurality of periodically arranged first adjustable units, and the longitudinal unit is composed of a plurality of transverse units; the first adjustable unit is provided with a pattern arrangement mode corresponding to surface impedance coding and spatial wave phase coding. In the application, the pattern arrangement mode of the first adjustable unit is designed through the surface impedance coding and the spatial wave phase coding, so that the surface wave is converted into a leaky wave and radiated to free space, and the spatial wave beamforming function is realized, thereby improving the beam regulation strength and the flexibility of the beam regulation.

The embodiment of the invention provides a gradient impedance surface structure for edge scattering suppression and a design method, the structure comprises a radar wave-absorbing coating material loaded at the edge position of a metal edge, and the surface impedance of the radar wave-absorbing coating material is gradually increased from the inner side of the metal to the outer side of the metal. According to the embodiment of the invention, the surface current is smoothly reduced by designing the gradually-changed surface impedance, so that the edge scattering is effectively suppressed, and the effectiveness and excellent performance of the broadband wide-angle edge scattering suppression effect are further verified through analogue simulation; moreover, the embodiment of the invention is simple, convenient and universal, the designed structure is simple and light, the RCS reduction effect is excellent, and the method has a wide application prospect in the electromagnetic scattering field control direction.