2149 results about "Narrow band" patented technology

The invention provides a wind generating set fault monitoring method and system based on voiceprint recognition, and the method comprises the steps: collecting gear box voiceprint signal data in real time, recording signal fluctuation caused by gear surface wear, and obtaining an original signal data set containing a frequency spectrum high-frequency component enhancement feature; a time-frequency analysis method is adopted for the original signal data set, non-linear interference of vibration signals is recognized, multi-scale decomposition is carried out, initial wear frequency spectrum narrow-band characteristics and medium-term harmonic components are separated out, and a frequency spectrum component set is obtained; extracting characteristic parameters related to modulation depth abnormal fluctuation from the frequency spectrum component set, identifying a gear pair meshing frequency change rule, and determining a distribution mode of a tooth surface contact noise proportion; and if the feature matching result shows that the deviation between the spectrum high-frequency component diffusion distortion feature and the reference feature library exceeds a threshold value, adding the tooth surface fatigue crack noise feature into the feature library to obtain a target feature library.

The invention relates to the technical field of optical lens defect detection, and particularly discloses an optical lens laser-induced damage on-line detection method and system, a linear polarizer and a narrow-band filter are connected in series in a detection laser light path, non-target polarized light is filtered through polarization direction matching, meanwhile, interference of the environment and scattered light is inhibited through the narrow-band filter, and the laser-induced damage on-line detection system is obtained. According to the method, external source noise such as ambient light and non-target polarized light is reduced through polarization matching and narrow-band filtering, randomness of speckle noise is offset through multi-angle collection and signal fusion in a visual detection mode, exposure is dynamically adjusted, an image is fused to improve the signal-to-noise ratio, noise and real signals are decoupled through self-supervised learning, and the real-time performance of the system is improved. Dust interference is removed in combination with morphological operation; a deep learning reasoning model enhances the damage identification capability in a noise environment, defocusing blur caused by mechanical vibration is eliminated through phase conjugate correction, and the influence of photoelectric conversion noise, dust interference and the like on the detection efficiency and accuracy is remarkably reduced through multi-link linkage.

The invention discloses a thyroid intraoperative real-time navigation method and a thyroid intraoperative real-time navigation system based on multi-mode optical fusion. The thyroid intraoperative real-time navigation method comprises the following steps: outputting visible light through an endoscope and coupling light waves of a narrow-band multispectral light source to irradiate an operative field, exciting parathyroid glands to generate near-infrared fluorescence, and receiving reflected visible light, split light, near-infrared fluorescence and laser speckle signals through an endoscope probe. And separating the composite optical signal into four channels, and respectively generating an anatomical structure color image, a blood vessel spectroscopic image, a parathyroid gland near-infrared fluorescence image and a laser speckle image. Performing decorrelation processing on the laser speckle image to generate a blood flow dynamic pseudo-color decorrelation speckle image; an anatomical structure, a blood vessel center line, a parathyroid gland contour and blood flow dynamic feature points are extracted through a multi-modal registration technology, after affine transformation space alignment is conducted, a comprehensive imaging map containing the anatomical structure, blood vessel distribution and parathyroid gland function marking information is generated through a wavelet fusion algorithm, and intraoperative multi-dimensional real-time tissue navigation is achieved.

The invention relates to the technical field of narrow-band filters, and discloses an ultra-low power consumption narrow-band filter implementation method based on a digital phased array system, and the method comprises the following steps: S1, collecting input signal data, carrying out the adaptive preprocessing, and generating preprocessed signal data; s2, performing digital beam forming processing based on the preprocessed signal data to generate digital beam forming data; s3, performing narrowband filtering parameter matching processing according to the digital beam forming data to generate narrowband filtering parameter data; in the narrowband filtering processing process, disturbance of environmental electromagnetic interference to a target signal is identified and eliminated in real time through adaptive noise suppression and a multi-dimensional signal preprocessing mechanism, so that the system can guarantee the pointing precision of digital beam forming, the pointing offset problem in the space signal capturing process is avoided, the accuracy of narrowband signal extraction is improved, and the accuracy of narrowband signal extraction is improved. And the reliability of filtering output and the signal fidelity are enhanced.

The invention relates to a digital lock-in amplifier based on a frequency adaptive technology and a weak signal acquisition system and method, and the system comprises a front-end signal processing module which is used for obtaining a weak signal to be detected; the frequency self-adaptive tracking module is used for performing fast Fourier transform on the frequency of the weak signal to be measured to obtain the position of the maximum spectral line so as to synthesize a frequency control word, further generate a local reference signal and simultaneously adjust the coefficients of a low-pass filter and a loop filter and the series adjustment mode of a carrier synchronization ring; the multi-rate narrow-band low-pass filter module is used for multiplying the digital signal by a local reference signal and then carrying out filtering and down-sampling on a high-frequency signal to obtain a plurality of mutually orthogonal difference frequency components; the vector operation module is used for carrying out vector operation on the plurality of mutually orthogonal difference frequency components to obtain the phase and the amplitude in the weak signal to be measured; and the man-machine interaction module is used for displaying and storing the phase and the amplitude in the weak signal to be detected.

The invention discloses a photoacoustic spectrum-confocal Raman spectrum multi-view-field high-dimensional imaging method and a photoacoustic spectrum-confocal Raman spectrum multi-view-field high-dimensional imaging device. Nanosecond pulse laser with adjustable wavelength is generated through a continuous spectrum nanosecond pulser and a narrow-band spectrum tuning module and cooperates with a microscopic detection module, a depth imaging module, a galvanometer system and an electric displacement table to obtain spatial three-dimensional data, a photoacoustic spectrum and a Raman spectrum under multiple view fields; shallow photoacoustic spectrum-Raman spectrum tomography and deep three-dimensional photoacoustic imaging are realized; correcting a photoacoustic spectrum quantitative error by using a spectrum decoupling algorithm, and fusing the multi-view-field data to generate multi-view-field high-dimensional photoacoustic spectrum-Raman spectrum data; high-dimensional data features are extracted based on a 3D convolution instance segmentation network, and quantitative analysis and spatial distribution visualization of blood oxygen, inflammatory factors and the like are achieved. According to the method, the limitation that substances are difficult to analyze in photoacoustic imaging is overcome, the contradiction between the imaging resolution and the penetration depth is solved, and an accurate analysis means is provided for diagnosis of diseases such as knee osteoarthritis and sepsis.

The technology described herein is directed towards resonators that incorporate or are closely coupled to transducers from which energy is harvested. The resonators can be unit cells of a metasurface configured for narrowband sound absorption by phase cancellation of the acoustic wave Electroacoustic transducers such as piezoelectric transducers can be positioned, e.g., at the neck ports of the resonators, to generate electricity as the air pressure of incoming acoustic waves enters the unit cells. Energy can be harvested from the electricity, and stored for usage and / or used directly to power a device. Such a device powered by the harvested energy can change the resonant frequency of the device, e.g., by changing temperatures in the resonators' air cavities, changing respective dimensions of the respective air cavities, or changing the resonant frequency of the unit cells resonators by changing respective airflow in the respective air cavities.

The technology described herein is directed towards one or more modular metasurfaces arranged with unit cells for sound absorption, in which the unit cells are based on Helmholtz resonators that are deployed proximate to a server, without substantially obstructing airflow from the server fan(s). Each sound absorbing unit-cells is designed and constructed based on a specific resonance frequency, and includes a neck portion and air chamber dimensioned to resonate at the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. The metasurfaces can be arranged in a modular frame structure of surrounding unit cells, positioned behind the server's fan(s), with an opening in the frame structure to facilitate airflow therethrough, without obstructing or substantially obstructing the airflow to the surrounding environment.

The technology described herein is directed towards modular metasurfaces arranged with unit cells for narrowband, wideband and / or multiband sound absorption, in which the unit cells are based on Helmholtz resonators that are deployed in a server rack, proximate to a server, without substantially obstructing airflow from the server fan(s). Each sound absorbing unit-cells is designed and constructed based on a specific resonance frequency, and includes a neck portion and air chamber dimensioned to resonate at the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. Differently-dimensioned unit cells can be built into a single metasurface module, thereby facilitating wideband and / or multiband sound absorption with that metasurface. The modular metasurfaces can be attached to the sidewalls of a server rack, or positioned in otherwise empty slots above and below a server, optionally coupled to blanking panels for covering the openings of those slots.

The invention provides a multi-source fusion spectrum cross-domain high-precision prediction method and system based on transfer learning. The method comprises the following steps: S1, acquiring spectrograms collected by a spectral imaging device under multiple wavelengths; s2, extracting various types of features from the spectrogram; s3, training a fusion model to obtain a trained fusion model; and S4, inputting a to-be-predicted spectrum into the trained fusion model, and outputting a result. According to the invention, 10 <-4 > nm-level wavelength prediction can be achieved in a common industrial camera system, and the level of a scientific research-level grating spectrometer (0.001-0.002 nm) can be reached / exceeded; on a narrow-band, middle-band and wide-band multi-scene cross-domain data set, the mean absolute error (MAE) can be reduced from the nanoscale to the magnitude of 10 <-4 > nm, and excellent robustness is kept under the conditions of noise, feature deficiency and few samples.

The invention relates to the technical field of medical image processing, in particular to a cross-modal image fusion detection system for endoscopic early cancer lesions, which comprises a data acquisition module for acquiring a white light endoscope and a narrow-band imaging image; the data annotation module carries out pixel-level annotation, and the data enhancement module amplifies a data set by using CycleGAN; the white light data module and the narrowband data module train feature extraction models respectively; the feature alignment and attention module solves the problem that feature scales and semantics between two modes are inconsistent, and efficient fusion is achieved. The edge enhancement module enhances feature extraction of small focuses through the generative adversarial network; the fusion model construction module fuses the features and the transition area data to generate a fusion model; and the output module processes the white light and the narrow-band imaging image and outputs a fused image. Through feature alignment, an attention mechanism and a CyclGAN data enhancement technology, the problem of insufficient medical image data is effectively solved, the model generalization ability is enhanced, and efficient and accurate early cancer focus detection is realized.

The invention relates to the technical field of leaf nitrogen content estimation, in particular to a method for establishing a grassland plant nitrogen content monitoring model based on a remote sensing technology. The method comprises the following steps: controlling an unmanned aerial vehicle platform carrying a narrowband multispectral camera and a linear polarization camera, and collecting a spectral image sequence and a polarization image group at an observation window with a solar zenith angle of 30-40 degrees; extracting a reflectivity value of each wave band in the spectral image sequence, calculating a reflectivity first-order derivative and determining a red edge position offset; extracting horizontal and vertical polarization components in the polarization image group, calculating a polarization degree and constructing a polarization degree difference index; and identifying the center of the fecal spot by searching a pixel with a local maximum polarization degree difference index and red edge position offset blue shift exceeding a preset threshold value. According to the method, excrement spot recognition and remote sensing description of the nitrogen influence range thereof are achieved through double-index complementation of the red edge position offset and the polarization degree difference index.

The invention relates to the technical field of fault diagnosis, and discloses a cable fault diagnosis method, system and terminal, and the method comprises the steps: applying a broadband excitation signal to a target cable, so as to excite the target cable to generate a first response signal; extracting multi-dimensional time-frequency features of the first response signal after adaptive wavelet threshold denoising, and matching a fault template of a preset cable reference model according to energy distribution features in the multi-dimensional time-frequency features; determining a fault area in a fault template corresponding to the target cable according to the propagation time and the propagation speed of the first response signal; applying the narrowband excitation signal to a fault area of the target cable to obtain an impedance spectrum; the resonant frequency point based on the impedance frequency spectrum and the corresponding impedance amplitude value are compared with a typical fault mode in a fault feature database, and the fault type and the fault position of the target cable are obtained; generating a diagnosis report of the target cable according to the fault type and the fault position; the cable fault diagnosis accuracy can be improved.

An internet of things (IoT) non-terrestrial network (NTN) device user equipment (UE) is described. The UE includes receiving circuitry configured to receive narrowband physical random access channel (NPRACH) configurations including NPRACH resource configuration, repetition parameters, orthogonal cover code (OCC) multiplexing methods and OCC multiplexing factors. The UE also includes transmitting circuitry configured to select an NPRACH resource and randomly select an OCC index for an OCC multiplexing. The transmitting circuitry is further configured to transmit NPRACH preambles with a configured OCC multiplexing method and a multiplexing factor.

The invention discloses a solid waste-based zinc chloride preparation process control method and system, and relates to the technical field of zinc chloride preparation, and the method comprises the following steps: obtaining a unified time base line, establishing a bubble phase reference field, collecting a sound-induced echo sequence, a micro-pressure waveform sequence and a light scattering sequence of a reaction liquid under the bubble phase reference field, and calculating the solid waste-based zinc chloride preparation process. Fusing to generate a bubble density space-time matrix; and performing reversible time-frequency rearrangement based on the bubble density space-time matrix, decomposing to obtain different frequency band distributions, extracting a narrow-band resident bubble group, calculating critical volume distribution and collapse precursor indexes, and constructing a dynamic risk fingerprint database. According to the method, a unified time base line and a bubble phase reference field are constructed, the bubble state is perceived in real time, collapse forebodes are recognized, a dynamic risk fingerprint database is established, directional intervention and reverse energy channel collapse nucleus extinguishing are achieved in combination with an energy aggregation node, finally closed-loop regulation is constructed through calibration write-back, the safety and stability of zinc chloride preparation are improved, and the method is suitable for large-scale popularization and application. And efficient utilization and clean production of solid waste are promoted.

The invention relates to the technical field of signal processing, and discloses a power equipment partial discharge signal denoising method and system, and the method comprises the steps: S1, generating an exponential decay type pulse signal simulating partial discharge, and superposing white noise and narrow-band interference into the exponential decay type pulse signal to generate a noisy signal; s2, decomposing the noisy signal into a plurality of intrinsic mode components through an ensemble empirical mode decomposition method, calculating a correlation coefficient and a kurtosis index of each intrinsic mode component, and identifying a noise component and a signal component based on the correlation coefficient and the kurtosis index; s3, wavelet threshold denoising is carried out on the noise components, and a wavelet threshold is dynamically adjusted for each noise component through a particle swarm optimization algorithm; and S4, reconstructing the de-noised noise component and the reserved signal component into a final de-noised signal, and evaluating the de-noising performance based on the signal-to-noise ratio, the root mean square error, the peak signal-to-noise ratio and the correlation coefficient.

The invention belongs to the technical field of oil stain detection, and particularly relates to a water surface oil stain detection method, system and equipment, the water surface oil stain detection system comprises a flexible circuit board FPC, an InGaAs infrared sensor, an infrared narrow-band filter and an optical lens, light enters a visible light camera and the optical lens through an external lens, the visible light camera collects visible light images, and the visible light images are transmitted to the InGaAs infrared sensor; the optical lens focuses a light beam, then light with a specific wavelength is screened out through the near-infrared narrow-band filter, the screened light is received by the InGaAs infrared sensor, and the InGaAs infrared sensor is connected with the FPC; the method has the advantages that visible light imaging and short wave infrared spectrum analysis technologies are ingeniously fused, so that the accuracy and the reliability of oil stain detection are remarkably improved. Under the current background that environmental protection and water resource management are increasingly severe, powerful technical support is undoubtedly provided for water surface pollution monitoring.

The technology described herein is directed towards a metasurface arranged with unit cells for narrowband sound absorption, in which the unit cells are based on Helmholtz resonators that can have their resonant frequencies selected via interchangeable portions. A sound absorbing unit cell is designed and constructed in two parts based on a desired resonance frequency, such as a neck portion and air chamber portion. The portions are dimensioned such that when coupled together, Helmholtz resonators are formed that resonate at a desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. A portion with different dimensions can be interchanged to adjust the resonant frequencies to cancel acoustic waves of different frequencies corresponding to noise, which can change over time. The unit cells can be distributed as part of a metasurface, which can be positioned proximate to a noise source to phase cancel the noise.

The invention provides a cavity target infrared characteristic calculation ray tracing method, and belongs to the technical field of infrared tracing. The method comprises the following steps: importing a CFD data source; a cuboid space grid is generated, and CFD data space distribution is interpolated and reconstructed; a target material and temperature parameters are set; determining the position of a detector and forming a detection situation relationship; gridding a detection space in the transverse direction and the longitudinal direction at the position of the cavity object to form a field pixel space; constructing a reverse ray vector direction, and counting self reflection and reflection radiation of each triangular infinitesimal according to a recursive iteration mode; reconstructing a broadband spectral reflection coefficient according to the narrowband BRDF model and the broadband spectral emissivity; and determining the reflection direction of the infrared rays based on a bidirectional reflection distribution model to realize ray tracing. According to the invention, the control of any ray tracing depth can be realized, the intersection judgment process is greatly simplified, and the problem of high-efficiency and high-precision calculation of the cavity and the low-emission material is effectively solved.

The invention discloses a calibration device with a spectrum self-calibration function and a high-resolution spectrum calibration method thereof. The device comprises a narrow-band light source, a broadband light source, an optical fiber isolator, a coupler, an interference system, a multi-way switch, an FP (Fabry-Perot) cavity, a collimator, an orthogonal dispersion system and a computer, wherein the orthogonal dispersion system consists of a cylindrical lens, a reflector, a virtual phase array, a grating, a focusing lens and an industrial camera; according to the device, different light source paths are gated, FP cavity modulation and orthogonal dispersion system light splitting are utilized, and an industrial camera is combined to receive light signals. According to the method, the mapping relation between pixels and wavelengths can be established, the two-dimensional spectrum is compressed into the one-dimensional calibration spectrum through light intensity modulation and normalization processing, the calibration process of the orthogonal dispersion system is simplified, and the measurement precision is improved; and system drift can be compensated in real time through self-checking calibration, and the reliability of a measurement result is ensured, so that accurate calibration and measurement of a high-resolution spectrum can be realized.

The technology described herein is directed towards a metasurface arranged with unit cells for narrowband sound absorption, in which the unit cells are based on Helmholtz resonators that can have their resonant frequencies adjusted via MEMS actuators. A sound absorbing unit-cell is designed and constructed based on a general resonance frequency, and includes a neck portion and air chamber dimensioned to resonate close to the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. A bimorph MEMS actuator and / or moveable part in the resonators, controlled by a controller, facilitates changing of the airflow the unit cells to adjust the resonant frequencies thereof, to cancel acoustic waves of different frequencies corresponding to noise, which can change over time. The unit cells can be distributed as part of a metasurface, which can be positioned proximate to a noise source to phase cancel the noise.

The invention relates to the technical field of satellite transmission service or radio transmission service of a space station or an airborne station, in particular to a narrow-band interference elimination method based on spread spectrum communication applied to satellite transmission service, which comprises the following steps: S1, performing FFT (Fast Fourier Transform) operation on a digital baseband signal, converting the digital baseband signal into a frequency domain signal, determining a judgment threshold according to the background noise power, and judging a component greater than the threshold as an interference signal; s2, based on a sequential return-to-zero algorithm or a sequential pruning algorithm, frequency points with interference signal components in each frequency domain under the AWGN condition are cut off; s3, using windowed FFT operation, and popularizing the application under the AWGN condition in the S2 to the application under the narrowband interference condition; and S4, reducing the frequency domain signal after the interference signal component frequency points are removed into a time domain signal by adopting IFFT (Inverse Fast Fourier Transform) operation. The method has a good application prospect in the fields of manufacturing of space-based satellite systems and other spacecrafts, manufacturing of satellite antennas and other communication system equipment, satellite transmission services and the like.

The invention relates to the technical field of data processing, and discloses a water meter data processing method, device and equipment based on the Internet of Things and a storage medium, and the method comprises the following steps: when a collection task is received, carrying out data collection on a water meter according to the collection task to obtain water meter data; performing initial processing on the water meter data according to the characteristics of the narrowband Internet of Things to obtain optimized data; formulating a data transmission strategy according to the network state of the base station, and transmitting the optimized data to the base station according to the data transmission strategy; after receiving the optimization data, the base station analyzes the optimization data to obtain a water consumption analysis result; based on the advantages of the narrowband Internet of Things in data acquisition, data processing and data transmission, the problem of data mistakes, omissions and missing caused by artificial subjective factors, severe environments and poor signals in a traditional meter reading system is solved, and accurate data support is provided for water supply operation planning.

The invention relates to a heterojunction composite material and a preparation method and application thereof, and belongs to the technical field of catalysts. The preparation method of the heterojunction composite material comprises the following steps: dispersing nano cadmium sulfide in water to obtain a nano cadmium sulfide dispersion liquid, then adding a triazinyl covalent organic framework, fully reacting at 75-85 DEG C, centrifuging, precipitating, washing and drying to obtain the heterojunction composite material. The narrow-band-gap semiconductor cadmium sulfide and the wide-band-gap semiconductor triazinyl covalent organic framework are compounded to form the heterojunction structure composite material photocatalyst, and the narrow-band-gap semiconductor cadmium sulfide and the wide-band-gap semiconductor triazinyl covalent organic framework interact with each other, so that the response range of sunlight is widened, separation and transfer of photo-induced electrons and holes are promoted, and the photoelectric conversion efficiency is improved. Therefore, the photocatalytic oxidation-reduction capacity of the catalyst is improved, and the photocatalytic performance of the catalyst is finally improved. The heterojunction composite material can be applied to the field of cleaning and environmental protection as a photocatalyst, and has excellent hydrogen production efficiency.

The invention discloses a terahertz amplitude-frequency-adjustable narrow-band absorber based on photosensitive silicon and a strontium titanate material, and relates to the technical field of terahertz metamaterial absorber application. The structure mainly comprises a gold substrate, a strontium titanate dielectric layer and a composite resonant structure array at the top. According to the invention, tunable materials of photosensitive silicon and strontium titanate are used, and the conductivity of the photosensitive silicon is changed by controlling the intensity of an external pump light source, so that the amplitude of an absorption frequency point is regulated and controlled; the dielectric constant of strontium titanate is changed by controlling the external temperature, and the frequency of an absorption frequency point is regulated and controlled, so that the effect of independent, continuous and modulatable amplitude-frequency is achieved. The terahertz function logic device has the advantages of being simple in structural design, flexible, tunable, high in functionality and the like, and a new thought can be provided for design of the terahertz function logic device.

Systems, apparatuses, methods, and computer products for fast wakeup recovery for narrow-band internet of things (NBIOT) systems are provided. The fast wakeup recovery may wakeup a NBIOT device from a sleep mode to an active mode. The fast wakeup recovery may identify a servicing cell for the NBIOT device to synchronize with. The fast wakeup recovery may be based on a coarse timing detection operation using a NPSS and a fine timing detection operation using a NSSS.

The invention discloses a communication method and device, which can improve the PBCH receiving performance of a narrowband terminal while saving the overhead of a common channel. The method comprises the following steps: an RAN node determines the length of a coding bit sequence of a physical broadcast channel (PBCH) according to a first numerical value E1, determines the coding bit sequence according to the length of the coding bit sequence and an information bit sequence of the PBCH, determines M symbols of the PBCH according to the coding bit sequence, and maps the first M1 symbols in the M symbols to a first time frequency resource, and mapping the remaining M-M1 symbols to a second time frequency resource, wherein M and M1 are positive integers greater than 1. Wherein the first numerical value E1 is the product of M1 and the modulation order, and M1 is the number of effective resource elements RE in the first time-frequency resource. The first time-frequency resource and the second time-frequency resource form a PBCH time-frequency resource. The subcarriers occupied by the first time-frequency resource and the second time-frequency resource are not overlapped. And the first type of terminal acquires the first M1 symbols mapped on the first time-frequency resource, and the second type of terminal acquires the M symbols mapped on the PBCH time-frequency resource.

The present invention relates to the field of nondestructive testing technology and provides a composite material damage imaging method based on the spatiotemporal cross-correlation of ultrasonic guided wave wavefields. The method comprises the following steps: S1, acquiring a wavefield signal of the plate being tested; S2, performing narrowband signal extraction on the wavefield signal; S3, filtering the wavefield signal after narrowband signal extraction; S4, shifting the wavefield signal to obtain wavefield signal cross-correlation features; and S5, using a convex hull algorithm to obtain damage imaging results. This method innovatively extracts the difference coefficient between wavefield signals as a basis for damage location, providing a new approach to feature extraction algorithms based on the time-frequency domain. This method enables automated identification of composite material delamination damage and is sensitive to both surface and internal damage.

The invention discloses an antenna unit radiator, a circularly polarized phased-array antenna unit and an antenna array, and belongs to the technical field of antennas. The circularly polarized phased-array antenna unit comprises an antenna unit radiator, a first dielectric layer, a metal patch, a second dielectric layer, a third dielectric layer and a metal ground layer which are arranged in sequence; two L-shaped microstrip probes which are orthogonally arranged are laid on the top of the third dielectric layer; the third dielectric layer is internally provided with feed metal columns in one-to-one correspondence with the L-shaped microstrip probes, the top ends of the feed metal columns are connected with the corresponding L-shaped microstrip probes, and the bottom ends of the feed metal columns are provided with feed ports. The antenna array is formed by the antenna unit array. The working bandwidth of the antenna can be expanded, the defect of the narrow-band characteristic of the microstrip antenna is overcome, the degree of freedom of design of the phased-array antenna is improved, impedance matching is facilitated, and the circular polarization performance of the phased-array antenna array is greatly improved.

The technology described herein is directed towards a metasurface arranged with unit cells for narrowband sound absorption, in which the unit cells are based on Helmholtz resonators that can have their resonant frequencies adjusted via a shared tuning element, e.g., a screw, or a piezoelectric actuator. A sound absorbing unit-cell is designed and constructed based on a general resonance frequency, and includes a neck portion and air chamber dimensioned to resonate close to the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. Collectively moveable floors in the resonators facilitate changing the resonators' air cavity dimensions, to adjust the resonant frequencies to cancel acoustic waves of different frequencies corresponding to noise, which can change over time. The unit cells can be distributed as part of a metasurface, which can be positioned proximate to a noise source to phase cancel the noise.