100 results about "Transmission coefficient" patented technology

The invention provides a composite board detection method and system, and relates to the technical field of board detection, and the method comprises the steps: carrying out the ultrasonic scanning of a composite board, dividing the composite board into a plurality of acoustic characteristic layers, building a sound wave propagation model based on a recursive transfer matrix method, and calculating the reflection coefficient and transmission coefficient of each layer interface. A deep learning algorithm is combined with physical constraints to dynamically correct acoustic parameters, the corrected parameters are substituted into a model reconstruction signal, and defects are accurately positioned. And performing grid division on the defect position to analyze stress field distribution, and determining a stress concentration position. And fine scanning is carried out on a stress concentration area by adjusting probe parameters, and high-resolution data is obtained to update defect distribution information. And finally, outputting detection data including defect positions, stress concentration distribution and hazard levels, and realizing accurate detection and evaluation of the defects of the composite board.

The invention provides a remote sensing water depth detection method, medium and system based on blue-green laser, and belongs to the technical field of water depth measurement, and the method comprises the steps: firstly, obtaining blue and green laser signals with known transmitting power, and collecting water surface reflection and water bottom reflection data under different incident angles; based on the data, a laser incident angle matrix is established, and a water surface reflection coefficient and a water surface transmission coefficient are calculated. Meanwhile, an atmospheric transmission matrix is established according to the meteorological parameters, and the transmission loss of the laser signal in the atmosphere is calculated. Then, a water surface fluctuation model is established, and water surface reflection and water bottom reflection signals are separated; and establishing a water depth calculation equation set by using the blue-green dual-wavelength signal intensity ratio matrix and combining with the optical characteristics of the water body. And finally, according to the propagation time difference and the equivalent propagation speed of the laser signal in water, solving a water depth equation set, and finally obtaining a water depth topographic map. The problem that in the prior art, a water surface reflection signal and a water bottom reflection signal cannot be separated, and the measurement precision is affected is solved.

The invention discloses a non-uniform sparse sampling single-section near-field test system and method, and belongs to the technical field of test. According to the method, the single-section radiation field is expressed in a matrix form, the unknown transmission coefficient is solved from the system of linear equations through an inverse matrix method, and the defect that a traditional single-section near-field test method based on fast Fourier transform depends on the distribution uniformity of near-field samples is overcome; under the assumption that antenna transmission coefficients have sparsity, a compressed sensing technology is introduced, L1 norm minimization constraint is applied to a transmission coefficient vector q to ensure the sparsity, and under the condition that the number M of single-section near-field samples is smaller than the number J of unknown coefficients, the transmission coefficients can be solved from an underdetermined linear equation set; according to the invention, a non-uniform sampling-based single-section near-field test method is realized, and the flexibility of a sampling mode is improved; the number of sampling points and the scanning time are reduced, and the testing efficiency is improved; and the far-field reconstruction precision is higher.

The invention provides a seismic wave field analytical simulation method, which comprises the following steps of: constructing a seabed interface analytical equation according to a displacement potential function and a boundary condition of reflected / transmitted waves; obtaining a first function relationship; obtaining a second function relationship; converting the seabed interface analytical equation by using the first function relationship and the second function relationship to obtain a function relationship between the reflection / transmission coefficient and the influence factor, and determining the function relationship as a third function relationship; a plurality of influence factors are obtained, and reflection / transmission coefficients corresponding to the influence factors are obtained based on the third function relation; and obtaining seabed seismic wave field data through forward modeling based on the influence factors and the reflection / transmission coefficients which are in one-to-one correspondence. According to the seismic wave field analysis simulation method, the obtained seabed seismic wave field is highly similar to real data, and a theoretical model can be provided for prediction and attenuation of seabed multiples and ghost waves.

The invention requests to protect a terahertz wave beam steering gear based on a Huygens metasurface, which relates to the technical field of terahertz, and is composed of five resonance units with different shapes and sizes in the horizontal direction, and the same units are periodically arranged in the vertical direction. Each resonance unit comprises a dielectric substrate PI (polyimide) and a metal structure. The metal structure in one resonance unit is composed of a plurality of metal strips, and a metal opening is designed between the specific metal strips in each group of metal structure. According to the terahertz wave beam steering device based on the Huygens metasurface, incident terahertz waves can be refracted and steered, and the terahertz wave beam steering device has a high transmission coefficient. The terahertz sensor is simple in structure and mature in manufacturing process, and has important application prospects in the fields of terahertz components, terahertz sensing and the like.

The invention relates to a brightness temperature imaging method and system for air hidden detection, and the method comprises the following steps: 1, carrying out the modeling of an air shielding detection model, and obtaining a model that a radiometer is buried in sandy soil and a detection object is above the sandy soil; 2, the model is subdivided into a plurality of small areas or grids; 3, setting different dielectric constants on the measured surfaces of the target object, the sandy soil and the atmosphere, performing ray tracing, and simulating a propagation path of millimeter waves from the sky to the ground; 4, taking the Green's second theorem as a starting point, and utilizing a Kirchhoff residence phase approximation method and a Kirchhoff scalar approximation method to solve the transmission scattering problem of the Gaussian rough surface; 5, inverting the brightness temperature to the emission source point according to the brightness temperature and the transmission coefficient of the ray terminal to obtain the total brightness temperature of each position; generating an unprocessed brightness temperature map in the detected scene through accumulation calculation of multiple reflections and transmissions of rays in each medium; and 6, performing data processing on the brightness temperature map by using Gaussian filtering, and outputting a brightness temperature imaging result.

The present invention discloses a method for obtaining rock joint stiffness. According to the displacement discontinuity method of stress wave in linearly deformed jointed rock mass, a function expression of transmission coefficient T is derived: a function relationship between incident harmonic and transmitted harmonic about joint stiffness is established in frequency domain; incident wave and transmitted wave are subjected to discrete Fourier transform in time domain to obtain a series of incident harmonic and a series of transmitted harmonic; according to the function expression of transmission coefficient T, a series of incident harmonic and transmitted harmonic data are combined to fit the joint stiffness k that makes the incident harmonic and transmitted harmonic data satisfy the transmission coefficient function expression. n This method only requires one tap on the rock mass to measure the strain change curves at two locations before and after the joint: the time-domain strain-time diagram of the incident wave and the transmitted wave. The joint stiffness of the joint inside the rock rod can be determined by inputting it into the program, which simplifies the experimental process and avoids secondary contamination of the core drilling measurement of the rock mass.

The invention discloses an energy selective surface with a low-frequency cross-band ultra-wideband characteristic. The energy selective surface comprises a top-layer metal structure unit, a middle-layer dielectric substrate and a bottom-layer metal structure unit. The top layer metal structure unit is composed of nine cross-shaped patch metal structures and PIN diodes, and the bottom layer metal structure unit is formed by rotating the top layer metal structure unit by 45 degrees. When high-power electromagnetic waves enter the structure, the PIN diode is conducted and is equivalent to a resistor, power protection is achieved within the range of 0-5.6 GHz, and the transmission coefficient is restrained to be below-15 dB; when a low-power electromagnetic wave enters the structure, the PIN diode is disconnected and is equivalent to a capacitor, wave transmission is realized in the range of 0-5.6 GHz, and the transmission coefficient is more than-3dB, so that the functions of low-power wave transmission and high-power protection are realized in the low-frequency range of 0-5.6 GHz, the suppression performance is enhanced, and the antenna housing has an application value for the design of a low-frequency antenna housing.

This application discloses a method, apparatus, device, and medium for self-calibration of an ultrasonic sensor for transformers. The method involves obtaining the spatial distance by using the time difference and measured sound velocity of the same partial discharge pulse received by a built-in UHF antenna and an external ultrasonic sensor; constructing a cross-medium model based on the acoustic parameters of the insulating oil and the tank to calculate the sound pressure transmission coefficient at the liquid-solid interface; constructing a spherical wave dissipation equation in viscous oil by combining discharge and fluid parameters, and calculating the theoretical sound pressure of the outer shell using the distance and transmission coefficient; comparing the measured peak output voltage of the external sensor with the in-situ acoustic-electric conversion sensitivity for online self-calibration. This method reconstructs a high-fidelity sound wave propagation attenuation model, which can improve calibration accuracy and diagnostic reliability.

The invention discloses an underwater submerged dike design and optimization method based on a weighted K-means method, and the method comprises the following steps: carrying out a test according to a test combination obtained through a D-optimal design method, and collecting test data; the collected test data are preprocessed, a transmission coefficient is calculated, and factors influencing the wave absorption performance of the submerged dike are determined; and clustering the transmission coefficients by using a weighted K-means clustering method, analyzing an obtained clustering result, and determining a parameter selection range capable of maximizing the submerged dike wave absorption performance. According to the underwater submerged dike design and optimization method based on the weighted K-means method, marine environment data can be more accurately analyzed, the submerged dike design precision is improved, the engineering cost is effectively reduced, the submerged dike stability and durability are improved, high universality is achieved, the method is suitable for design and optimization of different types of underwater submerged dikes, and the method is suitable for popularization and application. The calculation amount and complexity are greatly reduced, and a conclusion can be obtained in a short time.

The invention relates to an ultra-wideband frequency selective metasurface prediction method based on a rapid prediction algorithm, and belongs to the technical field of electromagnetic engineering. Comprising the following steps: acquiring a single-layer S parameter; phase-amplitude relation modeling is carried out; and constructing a multi-layer structure and optimizing parameters. According to the prediction method provided by the invention, transmission coefficients of units under different unit parameters and different air layer thicknesses can be quickly calculated as long as S parameters of a single-layer structure are obtained; through the innovative technical means, hundreds of hours and even longer time needed by traditional full-wave simulation are greatly shortened to the level of several minutes, and therefore the time expenditure of the simulation process is remarkably reduced. By means of the improvement, the design iteration efficiency is greatly improved, clear structure adjustment guidance is provided for researchers, and resource waste and time loss caused by dependence on blind trial and error and repeated simulation in the past are avoided.

The invention provides a method and a device for calculating microwave band transmission characteristics of a dielectric inlaid multilayer metal net. The method comprises the following steps: enabling a medium embedded multi-layer metal net to be equivalent to a single-layer Dyde dispersion model; under the single-layer Dyde dispersion model, obtaining an incident wave angular frequency; the incident wave angular frequency is substituted into a preset final dispersion equivalent formula, and the relative dielectric coefficient of the single-layer Dyde dispersion model is obtained through calculation; and on the basis of the relative dielectric coefficient and an SO-FDTD method, a microwave band transmission characteristic result of the dielectric inlaid multilayer metal net is obtained through calculation. A medium inlaid multilayer metal net is equivalent to a single-layer Dyde dispersion model, and the overall transmission coefficient is calculated through a final dispersion equivalent formula obtained through final fitting, so that the complex electromagnetic response of a multilayer structure can be simplified into a single and easy-to-process model on the premise of keeping the consistency of physical properties, and the overall transmission coefficient is calculated. On the premise of keeping sufficient physical accuracy, the calculation efficiency is improved, and the resource consumption is reduced.

The present invention solves the problem that existing methods for obtaining transmission coefficients through time-domain standard square wave calibration do not fully utilize prior information about the signal to be measured, and measurement accuracy can be further improved. This invention provides a method for calculating the transmission coefficient based on the calibration results of the measurement system's frequency-domain response and a library of waveforms to be measured. The method comprises the following steps: Step 1: Obtaining the frequency response of the electromagnetic pulse measurement system, constructing a library of waveforms to be measured A, and obtaining the value of each waveform feature point in the library A; Step 2: Calculating the output waveform of each waveform after passing through the electromagnetic pulse measurement system and obtaining the value of the output waveform feature point; Step 3: Based on the value of each waveform feature point in Step 1 and the value of the output waveform feature point of the corresponding waveform after passing through the electromagnetic pulse measurement system in Step 2, calculating the transmission coefficient k of the electromagnetic pulse measurement system. The method proposed by the present invention improves the measurement accuracy of the transmission coefficient method and is highly practical.

The invention relates to the technical field of ocean engineering, and discloses a wave characteristic numerical simulation method and system of a permeable breakwater structure. The method comprises the following steps: firstly, establishing a numerical model of a permeable breakwater structure, including pile foundation arrangement and geometric parameters of a breakwater body; then, wave condition parameters and structure parameters are set, and the structure parameters comprise the pile diameter, the pile distance, the water depth in front of the embankment and the wave overtopping amount; secondly, based on a computational fluid dynamics method, simulating interaction between waves and the permeable breakwater, and calculating a wave transmission coefficient and structural stress; and finally, analyzing the influence rule of each parameter on the wave transmission coefficient, and extracting the structural stress distribution under the wave action. According to the method, the wave characteristics of the open breakwater are systematically researched through a numerical simulation method, the design efficiency is remarkably improved and the physical experiment cost is reduced while the calculation precision is ensured, and a basis is provided for the optimal design of the open breakwater.

This invention discloses a method, apparatus, device, and medium for calculating electromagnetic waves in a geo-ionospheric waveguide. It obtains the pulse operating frequency set and medium parameter set of electromagnetic waves in a layered geo-ionospheric waveguide model. The electromagnetic waves consist of multiple electromagnetic waves to be calculated in different frequency bands. Based on the pulse operating frequency and medium parameter set of each electromagnetic wave to be calculated, a target calculation method for the receiving electric field is determined from multiple preset electric field calculation methods. The target transmission coefficient is determined based on the transmitting electric field at the emission point of each electromagnetic wave to be calculated, the layered geo-ionospheric waveguide model, and the target calculation method for the receiving electric field. The time-domain waveform of the electromagnetic waves is calculated based on the target transmission coefficients of multiple electromagnetic waves to be calculated and a preset electromagnetic pulse frequency domain calculation formula. In this way, the most suitable target calculation method for the receiving electric field is determined based on the pulse operating frequency set and medium parameter set of the electromagnetic waves to be calculated in different frequency bands, enabling accurate and rapid calculation of electromagnetic waves in a layered geo-ionospheric waveguide.

The application discloses an ultra-wideband polarization converter metasurface for converging lenses and spatial imaging. The cell of the metasurface is composed of two metal gratings, two pairs of L-shaped metal patches and two dielectric plates. The metasurface of the application works in the range of 0.5 to 1.8 THz, the transmission coefficient is greater than 0.87, the relative bandwidth reaches 113%, the polarization conversion rate remains close to 100%, and the phase covers 360°. The metasurface has the advantages of simple structure, small size, high bandwidth, good polarization characteristics, easy integration, low loss and simple preparation process. The metasurface combines the changes of geometric phase and amplitude, which can not only realize two-dimensional focusing lenses by using phase changes, but also realize spatial imaging functions by using amplitude changes. The research results show that the metasurface provides a new way for the flexibility of terahertz wave polarization and phase manipulation, and opens up a new way for the dynamic operation of terahertz wave fronts.

An antenna module is provided and includes a flexible circuit having a first antenna feed and a second antenna feed. The antenna module includes a ground plane. The antenna module includes a first antenna element coupled to the first antenna feed. The first antenna element includes a first ground short stub coupled to the ground plane. The first antenna element includes a first radiating element defining an omnidirectional radiation pattern. The first radiating element includes a first main segment extending along a first arcuate path. The antenna module includes a second antenna element coupled to the second antenna feed. The second antenna element includes a second ground short stub coupled to the ground plane. The second antenna element includes a second radiating element defining an omnidirectional radiation pattern. The second radiating element includes a second main segment extending along a second arcuate path oriented parallel to the first arcuate path. The first and second antenna elements have a transmission coefficient lower than −10 dB.

The invention relates to the technical field of ultrasonic detection, in particular to a method for eliminating an error of a curve measured by an ultrasonic rebound comprehensive method. The method comprises the following steps: acquiring actually measured data of an arch bottom measuring area and an arch top measuring area; further acquiring an environment difference index according to the high-frequency difference, the sound velocity value difference and the rebound value difference of the ultrasonic full-wave train signals of the two measurement areas; according to the difference between the sound velocity values of the two measuring areas and the sound velocity value of the standard model and the difference between the rebound value of the two measuring areas and the rebound value of the standard model, the distribution of environmental difference indexes is combined, and a current weighted fitting deviation coefficient is obtained; and finally, selecting the final compressive strength from the preset trial calculation set based on the weighted fitting deviation coefficient. According to the method, the environment difference index is constructed through the sound velocity, the rebound and the high-frequency transmission coefficient of the arch crown / arch bottom measuring area, the fitting deviation of the trial strength is subjected to asymmetric weighting, water-induced sound velocity virtual high is automatically exempted, abnormal rebound is blocked, and therefore the real compressive strength is decoupled under lossless blind measurement.

The invention discloses an electromagnetic pulse propagation calculation method based on a generalized propagation matrix and a transfer function method, and the method comprises the steps: determining the explosion point height and the receiving point height of an electromagnetic pulse, and constructing an ionosphere parameter on a propagation path; calculating a wave vector of the position of an electromagnetic pulse explosion point, and calculating a reflection coefficient matrix and a transmission coefficient matrix of the electromagnetic pulse which upwards penetrates through the ionized layer and downwards radiates to the ground through a generalized propagation matrix method; defining the type of the electromagnetic pulse, and calculating the amplitude of the superposed uplink and downlink electromagnetic waves at the explosion point position through the reflection coefficient matrix; in combination with a generalized propagation matrix method and a transfer function method, calculating the frequency spectrum and time domain waveform of the electromagnetic wave penetrating through the ionosphere at the explosion point position through inverse Fourier transform; time-frequency characteristic analysis is carried out according to the frequency spectrum and the time-domain waveform of the electromagnetic waves penetrating through the ionosphere, a time-frequency graph is obtained, the experiment cost is remarkably reduced, and efficient and low-cost theoretical support is provided for propagation of the electromagnetic pulses in the ionosphere.

The invention belongs to the technical field of microwave frequency selective surface and infrared reflection focusing composite metasurface structures and design. A unit of a microwave band adopts a layered structure of metal pattern-ceramic dielectric-air gap-silicon substrate. The metal pattern is a miniaturized design of a three-order nested square patch, and the unit period is only 0.164 times of the working wavelength. According to the invention, a passive factor of a silicon substrate of an infrared band and an air gap generated by actual processing are creatively converted into an active design degree of freedom, and through collaborative optimization, a transmission coefficient higher than 0.99 at a center frequency of 15GHz, a-1dB bandwidth greater than 30%, and excellent angle stability under oblique incidence of 0-45 degrees are realized. The unit reflectivity of the infrared band is higher than 99% and close to 1, phase modulation can be achieved, and the infrared metasurface has a convergence function. The device is simple in structure and easy to integrate, and a new scheme is provided for realizing a function integrated device of microwave and infrared bands.

The invention provides a design method of a straight hole type wave absorbing structure for an ecological revetment, and belongs to the technical field of ecological channel wave absorbing. The technical problems that in the prior art, bank slope vegetation is eroded by ship waves for a long time, riverway water quality is damaged, and the process of designing a wave absorbing structure is tedious are solved. According to the technical scheme, the method comprises the steps that S1, ship traveling wave elements are calculated; s2, calculating a transmission coefficient and a reflection coefficient; s3, calculating wave force; s4, determining a structure design environment, and establishing a relation; s5, carrying out stability checking calculation; s6, selecting vegetation; and S7, determining the overall design of the wave absorbing structure. The method has the beneficial effects that the building structure of the vertical wall body with the straight holes is arranged in front of the ecological revetment, the holes are formed in the wave absorbing structure, and the ship traveling wave elements are treated; the problems that bank slope vegetation is eroded, water circulation in front of and behind the wave absorbing structure is poor, and design is tedious are solved through the technical means that the size of the straight hole type wave absorbing structure is calculated through a theoretical formula.

The application relates to the technical field of antenna isolation test, and discloses an intelligent test method and system for multi-port antenna isolation performance, which comprises the following steps: sequentially testing the transmission coefficients of each group of to-be-tested ports of a measured antenna by using a network analyzer, and constructing an S parameter matrix; any group of to-be-tested ports comprises an excitation port and a response port, and the transmission coefficient is the ratio of the power of a scattering wave received by the response port to the power of an incident wave input by the excitation port; based on the S parameter matrix, the isolation of each group of to-be-tested ports at each frequency within the working frequency band of the measured antenna is calculated; the worst isolation of all groups of to-be-tested ports within the working frequency band is identified, and the worst isolation is marked as the isolation of the measured antenna. The application effectively avoids measurement errors and accidental interference, and improves the accuracy and reliability of the isolation test.

The present invention provides a method and device for calculating the microwave transmission characteristics of a dielectric-inlaid multilayer metal mesh. The method comprises: equating the dielectric-inlaid multilayer metal mesh to a single-layer Drude dispersion model; obtaining the incident wave angular frequency under the single-layer Drude dispersion model; substituting the incident wave angular frequency into a preset final dispersion equivalent formula to calculate the relative dielectric constant of the single-layer Drude dispersion model; and calculating the microwave transmission characteristics of the dielectric-inlaid multilayer metal mesh based on the relative dielectric constant and the SO-FDTD method. By equating the dielectric-inlaid multilayer metal mesh to a single-layer Drude dispersion model and calculating the overall transmission coefficient using the final dispersion equivalent formula obtained by the final fitting, the complex electromagnetic response of the multilayer structure can be simplified into a single and easy-to-process model while maintaining consistency in physical properties. This improves computational efficiency and reduces resource consumption while maintaining sufficient physical accuracy.

The present invention provides a method for evaluating the time-domain echo broadening characteristics of a transceiver co-located underwater vehicle, including determining the geometric model parameters of the underwater vehicle, determining the time-domain acoustic wave information under full-angle incidence and converting it into a frequency-domain signal, determining the coordinates of the incident point and the receiving point, evaluating the reflection coefficient and transmission coefficient of the underwater vehicle's outer shell at different frequencies under full angle, establishing a model according to the shell form of the underwater vehicle to calculate the full-angle target frequency-domain transfer function; processing the full-angle target frequency-domain transfer function and the incident frequency-domain signal to obtain the time-domain echo broadening characteristics of the transceiver co-located underwater vehicle, and comparing the index requirements to obtain an evaluation conclusion. The present invention takes the geometric model of the underwater vehicle, material parameters, and the incident signal under full angle as inputs, and realizes the evaluation of the time-domain echo broadening characteristics index of the transceiver co-located underwater vehicle.

The application discloses a microwave detection-based imaging method for internal corrosion state of a reinforced concrete structure, and comprises the following steps: S1, setting a moving step D1 and a scanning frequency f1 of a rectangular waveguide along an X axis and a moving step D2 and a scanning frequency f2 of the rectangular waveguide along a Y axis; S2, acquiring a position interval of a steel bar in a concrete base by scanning with the rectangular waveguide; S3, obtaining a reference value matrix Γ0 of the steel bar without corrosion by scanning the concrete base with the rectangular waveguide; S4, performing X-axis parallel scanning on the reinforced concrete base by using the rectangular waveguide to obtain a transmission coefficient matrix set Γ representing a corrosion degree of the steel bar, and labeling subsets in the transmission coefficient matrix set Γ according to the corrosion degree; and S5, importing the transmission coefficient matrix set Γ and position information of the corroded steel bar into MATLAB for data imaging processing to obtain a three-dimensional stereoscopic imaging diagram. According to the scheme, engineering and technical personnel can intuitively obtain the internal corrosion state of the reinforced concrete base.

This application relates to the field of simulation optimization technology, and discloses a multi-objective design method and system for floating photovoltaic wave energy protection based on numerical simulation. The method includes: performing numerical simulation on the geometric parameter set of the FB-WEC-OFPV integrated system to obtain the transmission coefficient, capture width ratio, and levelized cost of electricity (LCOE); calculating the negative cosine value of the gradient vector at each sampling point based on the transmission coefficient and the capture width ratio to obtain the attenuation-capture conflict intensity field; cyclically supplementing and updating the surrogate model using the gradient amplitude of the attenuation-capture conflict intensity field as a priority criterion to obtain a refined sample database; and selecting the Pareto optimal engineering solution set based on the indicators in the refined sample database and the frequency integral value of the attenuation-capture conflict intensity field through multi-objective genetic algorithm optimization and high-fidelity simulation verification. This application solves the problem that the surrogate model sampling strategy cannot identify the spatial distribution of attenuation-capture physical conflicts, leading to pseudo-Pareto solutions being mixed into the optimal solution set.

This application relates to the field of electromagnetic wave and microwave technology, and provides a method, apparatus, device, and storage medium for extracting field strength distribution. The method includes: acquiring scene data; obtaining the radiation pattern and transmission coefficient of the micro-aperture using a full-wave simulation method; generating a first field distribution of a target point within a first metal cavity using a ray tracing method; generating a second field distribution of a second simulated receiver using the ray tracing method and the radiation pattern of the micro-aperture, or generating a simulated signal source for a second simulated transmitter based on the field distribution of the first simulated receiver and the transmission coefficient of the micro-aperture, and then generating the second field distribution of the second simulated receiver using the ray tracing method. The field distribution within the first metal cavity can be obtained using the ray tracing method, and then the radiation pattern and transmission coefficient at the micro-aperture can be obtained using the full-wave simulation method. Combining the ray tracing method and the full-wave simulation method can optimize the accuracy of the field distribution extraction results without consuming excessive computer memory and computation time.

The invention discloses a Huygens metasurface-based terahertz phase shifter, which relates to the technical field of terahertz propagation and phase modulation and is composed of a plurality of terahertz units of rectangular resonant rings. Each resonance unit comprises a dielectric substrate PI (polyimide) and a metal structure. The metal structure in each resonance unit is composed of a plurality of metal strips. According to the terahertz phase shifter based on the Huygens metasurface, the stable high transmission coefficient can be achieved within the working frequency band of 0.4-1.0 THz, meanwhile, the transmission phase of the resonance unit covers the wide adjustment range of over 350 degrees, and therefore flexible and accurate terahertz wave phase adjustment and control are achieved. The structure is simple and fixed, the manufacturing process is mature and reliable, and important application prospects are achieved in the fields of terahertz components, terahertz imaging, terahertz communication and the like.

The application discloses a kind of underwater acoustic metamaterial equivalent parameter test methods: the incident signal and reflected signal of the front surface of material are measured, and the reflection coefficient R containing phase information under wide frequency is obtained;Transmission signal is measured on the back surface of material, and the transmission coefficient T containing phase information under wide frequency is obtained;According to R and T, the equivalent parameter is calculated using inversion method.The application also provides a kind of test system: signal testing device, including signal generator, transducer, hydrophone, power amplifier and oscilloscope;Three-dimensional moving device is used to control the position of transducer and hydrophone, and the incident signal, reflection signal and reflection signal are collected and recorded by oscilloscope;Signal post-processing module is obtained according to incident signal, reflection signal and reflection signal processing reflection coefficient and transmission coefficient, and equivalent parameter is calculated.The test method and system can obtain complex transmission and reflection coefficient with amplitude and phase information, so as to calculate the equivalent parameter of material by inversion method.

The application provides an array antenna mutual coupling calibration method and system based on spatial multi-scale feature decoupling, relates to the technical field of antenna testing, and comprises the following steps: placing a target antenna array in a full-wave anechoic chamber, connecting two ports to a vector network analyzer, and terminating the remaining ports with a matching load; measuring and obtaining the transmission coefficient between the two ports in a preset working frequency band to represent the coupling strength between the ports; repeatedly performing the measurement operation on multiple port pairs to obtain a scattering parameter matrix representing the mutual coupling effect; and comparing the scattering parameter with a preset technical index to determine whether the antenna isolation meets the requirements. The application can comprehensively and accurately represent the mutual coupling effect of a multi-channel antenna, avoid errors caused by reflection interference in the testing process, realize rapid determination and quality control of the isolation performance, and provide a reliable basis for the design optimization and engineering application of a base station antenna.