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2111 results about "Wide band" patented technology

Method for preparing single-layer tungsten diselenide nanoband based on space confinement strategy

The invention discloses a method for preparing a single-layer tungsten diselenide nanoband based on a space confinement strategy. By changing the flow and the growth time of hydrogen, effective control on the width and the thickness of a nanoband can be realized. The method comprises the following steps: uniformly spraying tungsten trioxide powder to one substrate, then covering the substrate by the other substrate, and forming micro reaction space which is of a 'sandwich'-like structure. Growth of a tungsten diselenide nanoband is carried out by utilizing a constant-pressure chemical vapor deposition method; physicochemical characteristics of a one-dimensional transition metal chalcogenide strongly depend on suspension key types on the edge of the one-dimensional transition metal chalcogenide, metallic properties are displayed by an ultranarrow band, and conversion from the metallic properties to semiconductor properties can be displayed from the edge to the center of a wider band; the tungsten diselenide nanoband is widely applied to micro-nano photoelectric devices due to the special property; industrial production of the tungsten diselenide nanoband can be realized through an experimental method of the invention.
Owner:XIANGTAN UNIV

Directional energy multi-target interference system based on ultra wide band phased array technology

The invention provides a directional energy multi-target interference system based on an ultra-wideband phased array technology, and the system integrates signal perception, target recognition, interference signal generation and phased array control, so as to achieve the precise interference of an unmanned aerial vehicle cluster. The signal sensing module scans an airspace target through the ultra-wideband phased-array antenna array and obtains spectrum characteristics of a target signal. The target identification module analyzes signal features, identifies an individual target and predicts a motion track and a communication protocol of the individual target. And the phased array control module calculates and adjusts antenna beam forming parameters, and dynamically controls the radiation direction, phase and transmitting power of the antenna. The interference signal generation module generates a matched interference waveform based on the target communication protocol and the trajectory information. The ultra-wideband phased-array antenna array adopts a digital beam forming technology. According to the invention, efficient and accurate directional energy interference can be realized under multiple frequency bands, the confrontation capability of the unmanned aerial vehicle cluster is improved, and the method is suitable for defense tasks in electronic warfare and complex electromagnetic environments.
Owner:ZHONGWEI JUNENG TECHNOLOGY (SHENZHEN) CO LTD

Distributed power transmission line fault diagnosis method based on ground potential end transient state information perception

The invention is suitable for the technical field of fault diagnosis, and provides a distributed power transmission line fault diagnosis method based on ground potential end transient information perception, and the method comprises the steps: collecting a broadband transient signal of each node ground potential end of a power transmission line; synchronously acquiring an electromagnetic transient signal and an environmental parameter through the composite sensing unit; performing dynamic filtering correction on the broadband transient signal according to a preset transmission line impedance matching model; a deep learning model is adopted to perform hybrid processing on the corrected broadband transient signals and electromagnetic transient signals, traveling wave head time-frequency features and power frequency abrupt change features are extracted, and fault probability and type classification results are output; verifying a fault positioning result through a multi-stage verification mechanism; the extracted characteristic quantity is preprocessed at the edge side of the detection terminal, and the processed data is transmitted to a master station system through an encryption protocol, so that the fault diagnosis accuracy of the distributed power transmission line is effectively improved.
Owner:广西电网能源科技有限责任公司

Intelligent circuit breaker leakage current test method, device and system

The invention particularly relates to a leakage current testing method, device and system for an intelligent circuit breaker, and relates to the technical field of electrical safety detection. A composite signal generation and injection module; a broadband signal acquisition and conditioning module; and a line fault positioning and impedance analysis module. According to the invention, the composite signal generation module realizes the non-interference isolation injection of a leakage current signal and a high-frequency positioning signal, and guarantees the high fidelity of data through adaptive filtering, multi-channel synchronous sampling and high-precision timing. The line positioning module integrates TDR and a frequency domain impedance method, and through multi-frequency point deviation correction and topology-GIS association, the fault type is accurately identified, and the test and troubleshooting period is significantly shortened.
Owner:BEIJING FEILING JIAJIE ELECTRONIC TECH CO LTD

Underwater sonar target detection system and method

The invention provides an underwater sonar target detection system and method. The underwater sonar target detection system comprises an optical fiber hydrophone array module which comprises a plurality of optical fiber hydrophone units, each unit comprises an optical fiber Bragg grating sensor and a sound pressure signal demodulation device, and the optical fiber hydrophone array module is used for collecting underwater sound wave signals in real time and converting the underwater sound wave signals into first electric signals; the sonar transmitting-receiving array module comprises a broadband sonar transmitter, a multi-beam receiver and a signal preprocessing circuit, and is used for actively transmitting a frequency modulation continuous wave signal, receiving a target reflection echo and generating a second electric signal; and the multi-mode signal fusion processing module comprises a high-speed data acquisition card, a self-adaptive noise suppression unit and a time-frequency analysis unit. The underwater sonar target detection system and method provided by the invention have the advantages of relatively high reliability, relatively high detection performance, relatively accurate cross-modal signal fusion and capability of performing intelligent target identification and tracking.
Owner:THE PLA NAVY SUBMARINE INST

Neural Network Accelerated Simulation Method for Wideband Target Group Radar Scattering Field

The present invention discloses a neural network accelerated simulation method for the radar scattering field of a wide-band target group, belonging to the technical field of electromagnetic simulation. The method of the present invention constructs a KAN neural network model at the central frequency of the wide band, and constructs KAN neural network models at other target frequencies through transfer learning or direct training; uses the trained KAN neural network model to generate a multi-frequency point numerical Green's function data set, and then constructs a wide-band training sample to train the multi-task learning model to realize the global prediction of the numerical Green's function of the entire target wide band; uses the numerical Green's function output by the multi-task learning model to realize the fast simulation of the scattering field of the wide-band target group. The method of the present invention can realize the fast and accurate simulation of the radar scattering field of the wide-band target group.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Distribution line broadband waveform sampling method

The invention discloses a distribution line broadband waveform sampling method, and belongs to the technical field of power system monitoring. By collecting quantum vacuum fluctuation noise, temperature, humidity and electromagnetic parameters, a quantum environment coupling entropy model is constructed, an optimal sparse base dictionary is dynamically generated, and a noise entropy break variable is calculated. And when the entropy break variable exceeds a threshold value, triggering sub-Nyquist compressed sampling, otherwise, adopting Nyquist rate sampling to realize dynamic matching of sampling resources and signal complexity. A high-frequency component of a compressed signal is reconstructed by combining an adversarial compressed sensing network with a residual network, a low-frequency component is generated based on an original signal, the distribution consistency of high and low frequency entropies is optimized by using a Wasserstein distance, and finally a three-dimensional waveform matrix containing a timestamp, a frequency bin and quantum entropy confidence is output. The problems of low sampling efficiency, poor sparse representation adaptability, slow noise response, inconsistent reconstruction and the like in a non-stationary signal and complex noise environment are solved, and the precision and energy efficiency of broadband waveform sampling are remarkably improved.
Owner:HONGHE POWER SUPPLY BUREAU OF YUNNAN POWER GRID

Large transformer noise monitoring analysis and fault early warning method and system

The invention discloses a noise monitoring analysis and fault early warning method and system for a large transformer, and relates to the technical field of noise monitoring, and the method comprises the following steps: collecting and preprocessing a coverage broadband noise signal through a sensor; a CNN-LSTM model is established for the collected noise signals through a deep learning module; and setting an early warning threshold value, performing judgment through the CNN-LSTM model, and triggering an early warning signal. According to the invention, key features can be automatically extracted from transformer noise, real-time analysis is carried out through the deep learning model, multiple fault types can be rapidly identified without manual intervention, early warning can be timely given out, power failure accidents caused by faults are reduced, the stability of power supply is improved, intelligent upgrading of a power equipment monitoring technology is promoted, and the power supply efficiency is improved. And a key technical support is provided for digital and intelligent transformation of the power industry.
Owner:SANXIA JINSHAJIANG YUNCHUAN HYDROPOWER DEV CO LTD

Broadband low-noise amplifier based on three-coil coupling transformer

The invention provides a broadband low-noise amplifier based on a three-coil coupling transformer. The broadband low-noise amplifier comprises an input matching network, a common-source differential output driving stage amplifier, an inter-stage matching network, a common-source differential output power stage amplifier and an output matching network which are connected in sequence, broadband matching is realized by using the input matching network and the inter-stage matching network, and the effective transconductance of the transistor is improved; through the cross-coupled capacitors, the LNA gain and stability on a broadband are improved, better isolation is realized, and input and output are decoupled; due to the design of the grounding capacitor, the linearity of the LNA is improved; through the combination of the three-coil coupling transformer and the differential topology, output signals are superposed in the same direction at the output end, and noise is cancelled in the reverse direction at the output end, so that the thermal noise is greatly inhibited, the isolation is improved through the output matching network, the insertion loss is reduced, and the output matching performance is optimized.
Owner:GUANGDONG UNIV OF TECH

Broadband high-gain microstrip antenna

The invention discloses a broadband high-gain microstrip antenna, which is provided with a rectangular radiation patch, a symmetrical grooving parasitic patch, a dielectric substrate, a metal bottom plate and a polytetrafluoroethylene support column, the rectangular radiation patch and the symmetrical grooving parasitic microstrip are attached to the upper layer of the dielectric substrate; a certain distance is formed between the rectangular radiation patch and the slotted parasitic patch and is used for coupling electromagnetic waves; the upper dielectric substrate is provided with two through holes for feeding; the metal bottom plate and the upper-layer substrate are fixed through four polytetrafluoroethylene supporting columns; a space is reserved in the middle to form an air substrate; and an SMA interface is arranged below the floor. According to the microstrip patch antenna, the forms of differential feeding and parasitic patch adding are adopted, the high gain and broadband characteristics of the microstrip patch antenna are achieved, the profile of the antenna is kept within 0.1 lambda, and the unipolar radiation pattern is achieved while high performance is guaranteed. In addition, the antenna is relatively simple in technical structure and convenient for later processing, can be used as an array unit for arraying, and meets the requirements of modern communication.
Owner:SHAANXI UNIV OF SCI & TECH

Ultra-wideband low-profile phased-array antenna

The invention belongs to the technical field of antenna engineering, and particularly relates to an ultra-wide-band low-profile phased-array antenna, which realizes broadband impedance matching characteristics and effectively expands the working bandwidth of the antenna by optimizing a dipole arm structure and introducing a matching branch knot and linear tapered slot composite structure on a radiation unit layer; on the array architecture level, an electromagnetic metasurface technology is adopted, array current distribution is improved through a periodic artificial electromagnetic structure, the active standing-wave ratio is remarkably reduced, the scanning angle of an array is widened, and meanwhile high compression of a system profile is achieved; on the structural design level, a three-dimensional composite structure of a transverse metal floor, a longitudinal radiation layer and a transverse metasurface layer is innovatively constructed, and the overall section height is reduced to 0.137 lambda Low (lambda Low is the lowest working frequency wavelength) through electromagnetic coupling and space folding technologies; in conclusion, the ultra wide band (the relative bandwidth is greater than or equal to 90%) and the low profile (lt; and the method is suitable for a new generation of broadband phased array radar system.
Owner:TIANFU WIRELESS INTELLIGENT RESEARCH INSTITUTE

Broadband planar array antenna light-operated beam forming method based on multi-task sparse learning

The invention relates to a broadband planar array antenna light-operated beam forming method based on multi-task sparse learning, and the method comprises the steps: deducing an array factor expression of a broadband array as priori knowledge through employing a rectangular planar array antenna; constructing a multi-frequency-point beam joint optimization model of the planar array antenna based on the neural network; based on the priori knowledge, calculating a total loss function of the model by using expected broadband array pattern data and a group inhaul cable regularization method, and training a multi-frequency-spot beam joint optimization model; and based on the trained model, obtaining the optimal array layout and the amplitude and delay distribution of each array element, and calculating to obtain a low-sidelobe directional diagram in which the deflection angle is irrelevant to the frequency. According to the invention, the deflection angle of the array radiation beam is kept constant in a broadband range, and the problem of'beam squint 'of a traditional phased array is solved; and meanwhile, the beam sidelobe level of each frequency point is effectively suppressed, and the grating lobe problem of the uniform array on the broadband is avoided.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Vehicle control method, vehicle, and storage medium

A vehicle control method is provided for a vehicle having an ultra wide band (UWB) sensor configured to measure a rainfall value. The method includes waking up the UWB sensor in response to a trigger instruction for starting rainfall detection, to cause the UWB sensor to measure a rainfall value; acquiring the rainfall value measured by the UWB sensor; and controlling the vehicle to execute a preset control instruction action according to the rainfall value.
Owner:BYD CO LTD

Method and system for capturing ultra wide band navigation signal of low earth orbit satellite

The invention discloses a method and a system for capturing an ultra-wideband navigation signal of a low-orbit satellite, which are used for solving the technical problem that the existing method for capturing the ultra-wideband navigation signal of the low-orbit satellite is easy to cause that the signal cannot be locked, and finally the capturing success rate is low. The method comprises the following steps: acquiring ka-band low-orbit satellite signals and low-orbit satellite pseudo-random noise codes corresponding to a plurality of low-orbit satellite ultra-wideband navigation signals; generating a complex signal and an original intermediate-frequency signal according to a preset sampling rate, preset skipping time and the ka-band low-orbit satellite signal; constructing a pseudo-code spectrum library based on the pseudo-random noise codes of the low-orbit satellites, and outputting the pseudo-code spectrum library; determining a discrete frequency search sequence based on known intermediate frequency parameters of the original intermediate frequency signal, performing matrix construction in combination with the complex signal and the pseudo code spectrum library, and outputting a three-dimensional result matrix; and capturing and judging the ultra-wideband navigation signals of the low-orbit satellites by adopting the three-dimensional result matrix, and determining a plurality of successfully captured ultra-wideband navigation signals of the low-orbit satellites.
Owner:SUN YAT SEN UNIV

Broadband sound absorption device using area division

The present invention relates to a broadband sound absorption device using area division, the device comprising: Helmholtz resonators including a neck portion and a cavity portion connected to the neck portion and having a predetermined area and thickness; and a unit sound absorber including at least one pair of the Helmholtz resonators, wherein a plurality of unit absorbers are arranged on a plane or curved surface, and the plurality of sound unit absorbers are formed to have cavity portions with different areas to minimize the thickness while enabling sound absorption for a wider band.
Owner:KOREA ADVANCED INST OF SCI & TECH

Tunable excited Raman spectrum microscopic imaging method and device

The invention discloses a tunable excited Raman spectrum microimaging method and device, and belongs to the field of spectrum detection and optical imaging. The device comprises a broadband adjustable wavelength light source, a high-resolution wavelength scanning module, a stimulated Raman signal excitation module and a stimulated Raman signal detection module. The stimulated Raman signal excitation and imaging module is used for focusing the two beams of narrow-band femtosecond pulse light which are overlapped in time and space on a sample and exciting a stimulated Raman signal, and meanwhile, moving the sample to realize spot scanning microscopic imaging; and the stimulated Raman signal detection module is used for converting the stimulated Raman scattering signal into an electric signal, demodulating the electric signal by using a lock-in amplifier, and recording spectral information by using a data acquisition card. According to the invention, the broadband tunable characteristic of the optical parametric amplifier is utilized to tune the pump light to the wavelength region of the sample absorption peak length so as to realize electron pre-resonance stimulated Raman; and a balance detection technology is combined at a detection end, so that high-sensitivity, high-resolution and high-signal-to-noise-ratio detection of stimulated Raman signals is realized.
Owner:BEIJING INST OF TECH

Frequency, polarization and directional diagram reconfigurable antenna unit and array

The invention provides a frequency, polarization and directional diagram reconfigurable antenna unit and array. The antenna unit comprises a tuning microstrip antenna unit and a reconfigurable feed phase-shift network which are stacked, the tuning microstrip antenna unit comprises a circular radiation patch etched with a circular gap and four variable capacitance diodes bridged on the circular gap; two output ports of a Wilkinson power division network in the reconfigurable feed phase shift network are respectively connected with two feed point micro-strips through PIN diodes, and four feed points form a structure which is in space symmetry and asymmetric in impedance. The circular radiation patch and the annular radiation patch in the antenna unit have continuity in structure, only four variable capacitance diodes are loaded on the annular gap, gain fluctuation is reduced, and the antenna unit is fed through four feed points which are symmetrical in space and asymmetric in impedance, so that the antenna unit is more stable in performance. Good matching can be kept between the feed phase-shifting network and the antenna unit in a broadband range, and the tuning bandwidth of the antenna is widened.
Owner:XIDIAN UNIV

Mine tight combination positioning method based on environment self-adaption

The invention relates to the technical field of high-precision positioning, in particular to a mine tight combination positioning method based on environment self-adaption, and aims to solve the problem of efficient positioning of personnel and equipment in a complex and limited space under a mine. The method comprises the step of acquiring a time difference of arrival measurement value through the ultra-wideband positioning tag and the positioning base station. Chi-square testing is carried out based on the innovation statistics of the extended Kalman filtering, and whether the environment is a sight distance environment is judged according to comparison between the innovation statistics and a threshold value. If the innovation statistic is lower than a threshold value, determining that the environment is a sight distance environment, and if the innovation statistic is higher than or equal to the threshold value, determining that the environment is a non-sight-distance environment. For a sight distance environment, high-precision coordinate estimation is obtained by adopting a time difference of arrival positioning algorithm, and a positioning result is optimized through extended Kalman filtering fusion. And activating the inertial measurement unit, constructing an ultra wide band / inertial measurement unit tight combination extended Kalman filtering model for a non-line-of-sight environment, and outputting a positioning result.
Owner:ZHONGBEI UNIV +1

Grid-connected inverter impedance detection method based on L-type filter

The invention provides a grid-connected inverter impedance detection method based on an L-shaped filter, and belongs to the technical field of grid-connected inverter impedance detection. A multi-frequency-point disturbance signal is injected into a preset grid-connected inverter working point, time domain data of inverter side current and common coupling point voltage are collected, fast Fourier transform analysis is carried out on the collected data, amplitude and phase information corresponding to each injection frequency point is extracted, and a frequency domain feature vector matrix is established; and establishing a frequency compensation matrix model to compensate and correct high-frequency band measurement data based on a frequency characteristic attenuation vector, calculating to obtain optimal estimated values of power grid impedance and grid-connected inverter output impedance, performing error analysis and precision verification on an impedance detection result, and outputting a verified impedance parameter value. The technical problem of insufficient power grid impedance detection precision caused by high-frequency band attenuation of the L-shaped filter is solved.
Owner:NENG KE TE KONG (BEIJING) TECH CO LTD

Metal microcrack ultrasonic detection method

The invention belongs to the technical field of metal crack detection, and discloses a metal microcrack ultrasonic detection method, which comprises the following modules: an ultrahigh frequency composite array probe with a center frequency dynamic adjustable range of 5-50 MHz; the dual-mode excitation and receiving module is used for independently generating a pulse reflection mode excitation signal and a diffraction mode chirp frequency modulation signal; the phase-controlled synthetic aperture dynamic focusing module is used for realizing + / -60-degree deflection and sub-wavelength level focusing of acoustic beams; the nonlinear harmonic enhancement module is used for exciting a crack nonlinear effect by superposing 1-2MHz fundamental waves; and a time-space-frequency three-domain data fusion module. According to the method, signal-to-noise ratio collapse caused by the diffraction effect in a traditional method is overcome, more importantly, the system has low-frequency penetrability and high-frequency resolution at the same time due to 80%-120% of broadband coverage of chirp frequency modulation signals, the diffraction signal gain is increased by 20 dB or above, a near-surface blind area is compressed to be within 0.2 mm, and the system can be applied to the field of radar imaging. And the core pain point of missing detection of the near-surface microcracks of the thin-wall component is solved.
Owner:ANHUA PRECISION TECH (SUZHOU) CO LTD

Electrical automation quality detection method and system

The invention belongs to the technical field of quality detection, and discloses an electrical automation quality detection method and system. The method comprises the steps of collecting original voltage and current signals of a PCC point of a power grid and performing FFT to obtain a background harmonic frequency set and a background harmonic amplitude set; generating an initial frequency grid based on a preset target frequency band, and generating a sparse frequency grid in combination with the background harmonic waves; calculating the estimated signal-to-noise ratio of each candidate frequency, performing ascending sorting to obtain an injection sequence, injecting sinusoidal signals, collecting PCC point voltage response and total current, and calculating a frequency impedance data pair; performing rational function fitting based on the frequency impedance data to obtain a broadband impedance curve; analyzing the curve, extracting quality characteristic parameters, and performing quality judgment according to the parameters; according to the method, the technical problem that the grid-connected stability quality of a single new energy converter cannot be quickly and automatically qualified in a production line offline detection scene in the prior art is effectively solved.
Owner:NANTONG SONGLIN TECH CO LTD

Microwave superheterodyne frequency sweep measurement system based on Rydberg atoms

The invention provides a microwave superheterodyne frequency sweep measurement system based on Rydberg atoms, and belongs to the technical field of microwave frequency measurement. The laser module excites detection light of 780 nm and coupling light of 480 nm, and the two beams of light are reversely input into the atomic gas chamber through the dichroscope; signal microwaves are generated by a radio frequency signal source and are radiated to the position of the atomic gas chamber through the horn antenna; local oscillation microwaves are generated by the microwave module and are also radiated to the position of the atomic gas chamber through the horn antenna; the atomic gas chamber serves as a mixer to form a difference frequency signal; the spectrum analyzer is used for monitoring low-frequency difference frequency signals generated in the frequency mixing process in real time and recording signal intensity in real time. According to the invention, high-precision and wide-band microwave frequency measurement is realized, continuous and smooth frequency sweeping response can be provided in a frequency range, and absolute frequency detection of microwave signals is realized under the condition that a complex frequency comb technology is not introduced. The hardware architecture is simplified, the automation degree is improved, and integration, popularization and application are facilitated.
Owner:UNIV OF SCI & TECH OF CHINA

Rapid detection method for resonant frequency of hemispherical harmonic oscillator

The invention relates to a rapid detection method for the resonant frequency of a hemispherical harmonic oscillator, belongs to the technical field of inertial measurement, solves the problems of long measurement time and low detection precision in the measurement of the second-order resonant frequency of the hemispherical harmonic oscillator in the prior art, and comprises the following steps: S1, providing a voltage excitation source, and applying a broadband sinc excitation signal to the hemispherical harmonic oscillator; s2, continuously recording the detection data in a set continuous recording time period; s3, performing frequency mixing to obtain data after frequency mixing; step S4, carrying out anti-aliasing filtering and down-sampling on the data after frequency mixing; step S5, carrying out N-point fast Fourier transform on the downsampled data to obtain a frequency spectrum of the detection signal; s6, based on the frequency spectrum of the converted detection signal, determining the frequency corresponding to the peak value of the frequency spectrum, and obtaining the measured second-order resonant frequency of the hemispherical harmonic oscillator; and S7, based on the measured second-order resonant frequency of the hemispherical harmonic oscillator, performing frequency phase loop, amplitude loop closed loop and orthogonal closed loop on the hemispherical harmonic oscillator.
Owner:TIANMUSHAN LABORATORY +1

Method for activating a vehicle function and associated activation device

The invention relates to a method for activating a function of a motor vehicle by means of an activation device comprising at least four ultra-wide-band communication external antenna modules and an ultra-high-frequency communication module, from an item of “hands-free” portable access equipment (SD) carried by a user, comprising an accelerometer, a gyroscope and a magnetometer, the activation of the function being triggered by detection of the presence of the user in a predetermined zone around the vehicle, and depending on an authentication result, the method comprising the following steps:s) determining an initial position of the item of access equipment with respect to the vehicle,t) measuring the values from the gyroscope, from the magnetometer and from the accelerometer,u) obtaining a value of the probability of the intention to activate a vehicle function,v) comparing the probability value with at least one predetermined threshold,w) transmitting, at ultra-high frequency from said item of equipment to said vehicle, a request to place the external antenna modules in partial or full ultra-wide-band communication operation, depending on the result of said comparison,x) activating the vehicle function, depending on an estimate of the distance between said item of equipment and the vehicle made by said external antenna modules thus activated in the ultra-wide band.
Owner:CONTINENTAL AUTOMOTIVE TECHNOLOGIES GMBH

All-dielectric structure type broadband wave-absorbing metamaterial and design method thereof

The invention discloses an all-dielectric structure type broadband wave-absorbing metamaterial and a design method thereof. The all-dielectric structure type broadband wave-absorbing metamaterial comprises a substrate and a plurality of resonators, the plurality of resonators are periodically and uniformly arrayed on the surface of the substrate, the adjacent resonators are connected with each other, each resonator comprises a pyramid structure unit and a grid structure unit, the pyramid structure units are nested in the grid structure units to form a pyramid-grid composite resonator, and the substrate and the resonators are both made of a high dielectric loss composite material. Based on the brand new design angle of wave absorbing performance complementation, the limitation of the wave absorbing performance of a single structure is broken through, the wave absorbing performance is improved from the microstructure level, meanwhile, efficient electromagnetic wave energy absorption is achieved in a wider frequency range, multi-stage dissipation and broadband impedance matching of incident electromagnetic waves are achieved, and the wave absorbing performance is improved. And the technical limitation of thickness constraint and narrow-band response of the traditional wave-absorbing material is broken through.
Owner:NORTHWESTERN POLYTECHNICAL UNIV

State monitoring method for bridge structure

The invention discloses a state monitoring method for a bridge structure, and belongs to the technical field of bridge measurement and monitoring, and the method comprises the steps: obtaining an original data set of the inclination angle of a bridge main tower and the tension of an inhaul cable, analyzing a signal time feature representation factor, and carrying out the linear interpolation adjustment information judgment; and based on the original data set, analyzing an inhaul cable tension update value, then analyzing an inhaul cable tension residual error and an interpolation adjustment effect label, and carrying out signal reconstruction effect judgment. According to the method, the bridge structure can be continuously monitored, linear interpolation adjustment information is carried out by analyzing signal time characteristic characterization factors, whether adjustment is carried out or not is judged, calculation power waste is avoided, and the inhaul cable tension is aligned with a main tower inclination timestamp by analyzing inhaul cable tension update values through linear interpolation adjustment. A stay cable tension update value is analyzed to eliminate a cross-sensor clock asynchronous error, signals are classified by analyzing a frequency coherence factor, mutual interference of different frequency components in broadband signals is avoided through classification processing, and the structural health monitoring precision is remarkably improved.
Owner:ZHUHAI DA HENG QIN URBAN PUBLIC RESOURCES OPERATION & MGMT CO

C / X wave band ultra-wideband GaAs MMIC low-noise amplifier

The invention discloses a C / X wave band ultra-wideband GaAs MMIC low-noise amplifier, and mainly relates to the technical field of radio frequency front ends. Comprising an input matching network used for receiving a radio frequency signal and performing impedance matching so as to effectively transmit the signal to a subsequent active amplification part; and the active amplification part adopts an improved cascode-cascode cascade amplification structure and is used for amplifying the radio frequency signal transmitted by the input matching network. The amplifier has the advantages that an improved cascode-cascode cascade amplification structure is adopted, the gain is improved through an improved Cascode structure, the noise coefficient of the circuit is reduced, and the performance indexes of ultra wide band, low noise and high gain are achieved. The design of the structure not only improves the overall performance of the amplifier, but also enables the amplifier to keep stable gain output in a broadband range, and effectively solves the problems of low gain and high noise of a traditional low-noise amplifier in broadband application.
Owner:HENAN NORMAL UNIV

High-voltage pulse generating device and testing system

The utility model provides a high-voltage pulse generating device and a test system. The high-voltage pulse generating device comprises a main control unit, a driving circuit, a pulse control circuit with a wide bandgap semiconductor power device, and an output circuit, the first end of the main control unit is coupled with the first end of the driving circuit, the second end of the driving circuit is coupled with the first end of the pulse control circuit, and the second end of the pulse control circuit is coupled with the output circuit; the main control unit is configured to generate two paths of first PWM (Pulse Width Modulation) signals with dead time control; the two paths of first PWM signals are sent to the driving circuit; and the driving circuit is configured to process the first PWM signal and then drive the pulse control circuit, so that the output circuit generates a high-voltage pulse signal. According to the utility model, the structure is simple, the cost can be greatly reduced, the output pulse speed can be flexibly set, and the CMTI test requirements of different isolated gate drivers can be met.
Owner:XINLIAN ADVANCED INTEGRATED CIRCUIT MANUFACTURING (SHAOXING) CO LTD

Composite multi-frequency marine ultrasonic antifouling system and method

The invention discloses a composite multi-frequency marine ultrasonic anti-fouling system and method, relates to the technical field of marine anti-fouling, and aims to change a single-frequency or simple-pulse ultrasonic transmitting mode, transmit composite multi-frequency ultrasonic waves in a wide frequency band, and superpose the ultrasonic waves of multiple frequencies in a transmission medium to generate a cavitation effect so as to achieve the anti-fouling effect. The method is used for avoiding the tolerance of marine organisms, improving the anti-adhesion efficiency and enhancing the effect of a specific area; the wave generating frequency and the working frequency are dynamically adjusted according to the running state and the environment condition of the ship, the energy consumption and the biological adhesion rate of the ship are reduced, and the relation among the biological adhesion rate, low energy consumption and the environment protection requirement is balanced.
Owner:FUJIAN AIDI ELECTRIC CO LTD

Ultra wide band direction finding information extraction method based on multi-input single-output delay overlay network

The invention discloses an ultra wide band direction finding information extraction method based on a multi-input single-output delay superposition network. The method comprises the following steps: acquiring an antenna receiving signal and an attitude transformation matrix of an antenna; processing an antenna receiving signal to obtain a time point of a first peak leading edge detection threshold value and pulse sequence data in a complex form; carrying out 64-time up-sampling processing on the pulse sequence data in the plural form, and drawing an amplitude-time curve and a phase-time curve; determining a peak value corresponding to the adjacent antenna according to the peak value leading edge time point; calculating the peak values corresponding to the adjacent antennas to obtain the time difference of arrival and the phase difference of the adjacent antennas; and ultra-wideband direction-finding information positioning is realized. According to the invention, group delay can be carried out on the ultra-wideband pulse signal by adopting the delay line with the given length, and the ultra-wideband direction-finding information positioning precision is improved. The ultra wide band direction finding information extraction method based on the multi-input single-output delay overlay network can be widely applied to the technical field of ultra wide band positioning.
Owner:FOSHAN UNIVERSITY +1