1350 results about "Frequency selection" patented technology

A tracking and adaptive compensation method for power fluctuation of a pulse load of a ship is provided. The method includes: based on a microgrid topology model of the ship, a pulse load model of the pulse load, and an interharmonic power and pulse parameter relationship model, performing power fluctuation tracking, frequency selection and a power spectrum analysis to obtain filtering parameters of a low-pass filter and filtering parameters of a band-pass filter; performing waveform adaptation to eliminate a phase delay caused by the low-pass filter and the band-pass filter, and obtaining a control command for a power compensation strategy; and generating, by a power loop, a pulse width modulation (PWM) signal to control a switching tube in a bidirectional direct current (DC) / DC converter of each of an energy storage battery pack and a supercapacitor of a hybrid energy storage system.

The invention overcomes the constraints imposed by conventional wireless communication standards by introducing a physical-layer optimized architecture that decouples transmission control from any single protocol. Rather than being confined by the predefined behaviors of LTE, 5G NR, Wi-Fi, or NB-IoT, the system implements a unified control system that dynamically manages radio parameters—such as modulation, coding, and power—based on real-time link quality and network context. This cross-standard, multimode capability effectively supersedes traditional standard-driven implementations, enabling adaptive, low-latency, and spectrum-efficient communication in complex heterogeneous environments.The system dynamically controls radio access network (RAN) and physical layer parameters, including carrier aggregation, dynamic spectrum allocation, modulation and coding scheme (MCS) adaptation, beamforming configuration, channel coding, transmit power control, and frequency selection. The system architecture includes multi-mode base stations, relay nodes, and edge access points that support inter-RAT handover, fast radio link recovery, and seamless mobility across diverse wireless technologies.

The invention relates to the technical field of power system management, in particular to a Beidou-based power grid emergency wireless communication monitoring system, which comprises a Beidou No.3 communication subsystem for realizing power business data encryption transmission, positioning and long message processing through a Beidou data transmission terminal and a handheld terminal; the short-wave communication subsystem establishes a communication link by using an autonomous frequency selection technology when no public network coverage exists; the Tiantong satellite communication subsystem provides voice and real-time data transmission service by means of a Tiantong satellite terminal; the converged communication control module dynamically switches communication links according to the channel quality, the service priority and the energy consumption index; the protocol conversion module realizes mutual conversion between electric power meter reading and a Beidou protocol; and the unmanned aerial vehicle relay extension module constructs an air relay link with the ground relay base station through the unmanned aerial vehicle group to extend Beidou signal coverage. According to the invention, efficient, reliable and wide power grid emergency communication is realized, and remarkable creativity and practicability are achieved.

A system for material detection and identification including: an RF transmitter configured for transmitting into an environment an RF signal at a first resonance frequency for a target material, wherein the first resonance frequency is obtained from a material database associating each of a plurality of materials with one or more corresponding resonance frequencies; an RF receiver configured for receiving a resultant response signal from the environment; and a processor configured for: analyzing the resultant response signal for resonance characteristics that indicate a presence of the target material, wherein analyzing includes, if the resonance characteristics are detected and no other material in the material database shares similar resonance characteristics for the first resonance frequency, reporting to a user that the target material has been identified.

The invention discloses a medical image fuzzy boundary segmentation system and method based on COD frequency domain guidance. In order to solve the problem of boundary fuzzy segmentation of a medical image under a complex background, frequency domain feature processing and an improved camouflage target detection (COD) algorithm are innovatively combined, and a progressive boundary optimization segmentation framework FEA-Net is designed. According to the framework, four key modules are designed: a semantic edge enhancement module (SEEM) realizes boundary preliminary positioning through space-channel self-attention; on the basis of SEEM, a frequency domain feature guide enhancement module (FTEM) further improves boundary prediction precision by using Fourier transform and adaptive frequency selection; an adaptive edge feature module (AEFM) highlights key boundary features; a Context Attention Aggregation Module (CAAM) implements feature fusion. Experiments show that evaluation indexes of the method on data sets of Kvasair-SEG, ISIC2018 and KPIs2024 are remarkably improved, particularly, obvious advantages are shown when boundary fuzzy areas are processed, and reliable support is provided for accurate segmentation of medical images.

A lightweight absorption-transmission integrated metamaterial to electromagnetic waves with polarization stability and wide-incident-angle stability, which has a symmetric structure including at least one square frequency-selective structure-unit arranged periodically. The square frequency-selective structure-unit includes a first dielectric substrate, a metal array structure layer, a second dielectric substrate, a first carbon-based conductive film array structure layer, a third dielectric substrate, and a second carbon-based conductive film array structure layer, which are laminated in sequence with the first dielectric substrate as the bottom. A method for preparing such lightweight absorption-transmission metamaterial to electromagnetic waves is also provided.

The present disclosure provides a frequency selective reflector reflecting electromagnetic waves in a particular frequency band to a direction different from a regular reflection direction, the frequency selective reflector including a plurality of regions and a function of adjusting a reflected beam profile.

The invention relates to an imaging type non-contact gating signal obtaining method for a magnetic resonance system, and belongs to the field of physiological signal detection.The method comprises the steps that pulse and respiration signals of a magnetic resonance detection patient are collected through a camera, and face information of the patient is obtained through a reflector in a magnetic resonance instrument cavity; a living body skin detection technology is utilized to efficiently select a region of interest of the face of a patient, and an IPPG technology is combined to process a video image to obtain a curve of image gray along a time sequence; a motion detection algorithm is used for tracking micro motion of the chest, and stable and accurate breathing signals are extracted by combining frequency selection. By analyzing and quantifying pulse wave signals and delay of respiration signals and electrocardiosignals, the purpose of replacing electrocardiosignal R-peak gating triggering with pulse wave and respiration signal feature triggering is achieved. The invention provides an imaging type non-contact gating technology to solve the problems that traditional ECG and other contact gating technologies are easily affected by a strong static magnetic field, an alternating gradient magnetic field and a radio-frequency pulse electromagnetic field in a magnetic resonance imaging system, and motion artifacts can be generated on motion of fluid such as human blood, breathing and cardiac contraction. Therefore, the quality of a magnetic resonance imaging image is improved.

The present application provides a frequency selective surface structure, an antenna system, and a base station. The frequency selective surface structure comprises a frequency selective surface, a feed network, and a phase shifter. The frequency selective surface comprises a metal layer, the phase shifter is electrically connected to the feed network, and the phase shifter and the feed network are integrated into the metal layer of the frequency selective surface. When the phase shifter does not obstruct an antenna beam, the frequency selective surface structure may reduce transmission loss, and both coverage range and transmission quality of an antenna signal may be considered, solving the problem of difficult layout of a phase shifter in a multi-band integrated antenna system.

The invention provides a high-frequency band-pass radar and infrared dual-stealth optical transparent metamaterial, and aims to overcome the defect that an existing stealth material cannot have optical transparency, infrared low emission, microwave broadband absorption and high-frequency band-pass at the same time. The antenna is formed by periodically arranging a plurality of structural units, and each structural unit sequentially comprises a low infrared emission layer, a first transparent dielectric substrate, a radar wave absorbing layer, a second transparent dielectric substrate and a frequency selection wave-transparent layer from top to bottom; the low infrared emission layer and the radar wave absorbing layer are respectively composed of a square patch array made of a transparent conductive material and a low duty ratio circular ring; the frequency selection wave-transparent layer is composed of a square ring aperture type metal mesh. Optical transparency, infrared stealth and radar stealth are integrated, meanwhile, the band-pass performance is achieved in the high-frequency guidance wave band, and the high application prospect is achieved in the field of actual engineering.

The invention relates to the field of electromagnetic functional composite materials, and particularly discloses a multi-layer composite structure flexible frequency selective surface material and a preparation method thereof. The ultra-high molecular weight polymer fiber-reinforced polymer-based composite material thin-film mechanical enhanced band-pass frequency selection array sequentially comprises an acrylic acid polyvinylidene fluoride organic polymer coating environment-resistant layer, a metal oxide organic film isolation layer, an ultra-high molecular weight polymer fiber-reinforced polymer-based composite material thin-film mechanical enhanced layer, a band-pass frequency selection layer and a packaging protection layer from top to bottom, and the band-pass frequency selection layer is a hexagonal / circular ring nested band-pass frequency selection pattern array. The packaging protection layer is formed by printing a conductive coating composed of conductive filler / polymer resin matrix, and the packaging protection layer is an ink coating. The flexible frequency selective surface material has the characteristics of light weight, high strength, salt fog / rain / ultraviolet and other severe environments, frequency selective wave transmission and multiple functions, has good gas barrier property, is beneficial to maintaining the shape of an inflatable hangar made of a skin and ensuring normal operation of radar equipment, and has good practical engineering application value.

An antenna system includes a radiating element layer including a plurality of radiating elements, a reflective frequency selective surface (FSS) layer having a resonance transmission frequency range, and an absorptive FSS layer between the reflective FSS layer and the radiating element layer and having a resonance absorption frequency range. The resonance transmission frequency range is greater than the resonance absorption frequency range.

A system for material detection and identification including: an RF transmitter configured for transmitting into an environment an RF signal at a first resonance frequency for a target material, wherein the first resonance frequency is obtained from a material database associating each of a plurality of materials with one or more corresponding resonance frequencies; an RF receiver configured for receiving a resultant response signal from the environment; and a processor configured for: analyzing the resultant response signal for resonance characteristics that indicate a presence of the target material, wherein analyzing includes, if the resonance characteristics are detected and no other material in the material database shares similar resonance characteristics for the first resonance frequency, reporting to a user that the target material has been identified.

Methods and apparatuses for frequency selective beam management. A method performed by a user equipment (UE) includes receiving first information related to a plurality of frequency subbands and receiving, in a first part of a downlink control information (DCI), at least one first transmission configuration indication (TCI) state and second information related to a second part of the DCI. The method further includes determining, based on the first information, a first association between the plurality of frequency subbands and the at least one first TCI state; for a first frequency subband from the plurality of frequency subbands, determining a first TCI state based on the first association; and identifying, based on the determined first TCI state, a spatial domain filter for transmitting or receiving UE-dedicated channels or signals for the first frequency subband.

The invention discloses a method and a system for suppressing electromagnetic interference in multi-modal fusion touch interaction. The method comprises the following steps of: acquiring signal data, extracting signal features to obtain a first signal data set, and extracting interference source features to obtain interference source feature data; performing spectrum conflict analysis according to the interference source characteristic data to obtain a conflict frequency range; when the conflict frequency range exceeds a preset frequency threshold value, performing dynamic frequency selection and sensor parameter adjustment to obtain a second signal data set, and performing intensity detection to obtain residual interference intensity; when the residual interference intensity is higher than a preset intensity threshold value, carrying out dynamic encryption operation to obtain an encrypted signal flow, and carrying out key dynamic updating and optimization to obtain an anti-interference touch signal flow; and according to the anti-interference touch signal flow, performing interference suppression effect quantification to obtain a final performance evaluation result of electromagnetic interference suppression. The method can realize real-time high-reliability electromagnetic interference suppression in a complex human-computer interaction scene.

The invention discloses a dither signal filtering and sampling method based on a TFLN laser. The method comprises the following steps: step 1, loading a fundamental wave / second harmonic of a low-frequency dither signal into a photo-generated current of an optical module; 2, the photo-generated current signal loaded with the fundamental wave / second harmonic of the dither signal is amplified through an operational amplifier circuit and then is divided into two paths to be output; 3, after the first path of output in the two paths of output passes through a low-pass RC filter circuit, optical power sampling is carried out to monitor optical power, and the second path of output in the two paths of output is divided into a fundamental wave branch and a second harmonic wave branch; 4, enabling the fundamental wave branch and the second harmonic wave branch to pass through a corresponding frequency-selecting filtering and amplifying circuit and a rear-end amplifying and biasing circuit respectively to obtain a fundamental wave signal and a second harmonic wave signal, and outputting the fundamental wave signal and the second harmonic wave signal to an ADC sampling module for sampling. According to the invention, effective sampling of the fundamental wave and the second harmonic wave of the dither is realized.

The present disclosure provides a frequency selective reflector reflecting electromagnetic waves in a particular frequency band of 24 GHz or more in a direction different from a regular reflection direction, the frequency selective reflector comprising: a reflecting member reflecting the electromagnetic waves; and a dielectric layer that is disposed at an incident side of the electromagnetic waves with respect to the reflecting member and transmits the electromagnetic waves, the dielectric layer has two types of thicknesses, and includes a plurality of first regions with thinner thickness and a plurality of second regions with thicker thickness.

The invention discloses a bilateral steep-drop wide-passband frequency selective surface with a stable angle. The unit structure of the frequency selective surface sequentially comprises a first metal layer, a first dielectric substrate, a second metal layer, a second dielectric substrate and a third metal layer from top to bottom, the frequency selective surface units are regular hexagons, and the units are closely arranged in an equilateral triangle grid form; the first metal layer and the third metal layer are identical in structure and are composed of six identical petal-shaped metal patches which are in rotational symmetry. The second metal layer is a regular hexagonal ring; the overall structure is symmetrical about the second metal layer. According to the invention, while wide-passband filtering is realized, the bilateral steep drop characteristic of the passband is considered, the stable passband characteristic can be maintained under the condition of oblique incidence, and in addition, the filter has a relatively low section and is easy for curved surface conformal.

An antenna system includes a first antenna and a second antenna. The first antenna includes a first radiating element, a first frequency selective surface, and a first feed network. The first radiating element is disposed on a side of the first frequency selective surface, and the second antenna is disposed on a side that is of the first frequency selective surface and that is away from the first radiating element. The first frequency selective surface includes a plurality of first strip-shaped structures and a plurality of second strip-shaped structures. The first strip-shaped structures and the second strip-shaped structures are made of metal. The plurality of first strip-shaped structures intersect with the plurality of second strip-shaped structures to form a plurality of grids. The first feed network includes a first structure, and the first structure is disposed on the first strip-shaped structure.

The invention relates to the technical field of radar measurement, in particular to a radar height measurement and radio frequency transceiving integrated system which comprises a signal processing module, a channel linkage scheduling module, a path stability judgment module, a frequency distribution management module and a positioning path feedback module. According to the invention, through amplitude peak point and time drift extraction, energy sudden change identification precision is enhanced, signal feature discrimination is improved, a screening channel is matched by using a beam main lobe and an energy center, efficient coupling of direction and energy is realized, path stability analysis introduces power attenuation and energy continuity evaluation, and available section identification accuracy is improved. The signal-to-noise ratio and the channel stable value are considered in frequency selection, the path spectrum utilization continuity is enhanced, frequency mapping is combined with round-trip time difference and height point coverage, the vertical positioning precision and the beam drop point judgment capability are improved, and the adaptability and reliability of radar measurement in a dynamic environment are integrally enhanced.

The invention relates to the technical field of mobile wireless network communication, and provides a multi-hop wireless ad hoc network and a centerless distributed frequency selection networking transmission method thereof. The method comprises the steps of networking control based on a service frequency hopping channel, spectrum sensing and spectrum evaluation, frequency selection negotiation based on neighbor nodes, time-frequency resource scheduling based on frequency selection, and frequency selection optimization based on data transmission. On the basis of TDMA channel access design, a networking control mechanism based on a service frequency hopping channel is designed, and nodes dynamically select available frequency channels for network service transmission in a distributed mode. Available frequency spectrum information is obtained through autonomous frequency spectrum sensing and frequency spectrum evaluation of nodes, frequency selection negotiation is performed between adjacent network nodes, and dynamic scheduling use of time-frequency two-dimensional resources is performed in combination with a frequency selection result, so that data transmission of network centerless distributed self-adaptive frequency selection is realized; and the reliable networking and communication capabilities of the network in a complex electromagnetic interference environment are enhanced.

The invention discloses a table data frequency domain anomaly detection method based on wavelet decoupling and adaptive reconstruction, and belongs to the technical field of anomaly detection. Aiming at the problems of insufficient utilization of data relevance and neglect of frequency domain mode difference in the prior art, spectrum decoupling is realized by constructing a Beta wavelet filter bank, and detection is performed in combination with an adaptive frequency selection module and a full-band reconstruction mechanism. The method specifically comprises the following steps: (1) constructing a table graph model based on a thermonuclear function, and quantifying node relevance; (2) realizing multi-scale frequency domain decomposition by adopting a compact support Beta wavelet, and separating a normal data core mode; (3) designing an alternating encoder-attention architecture, and dynamically screening key frequency components; and (4) constructing an anomaly scoring system through the reconstruction error. Through verification of 23 cross-domain reference data sets, the AUC-ROC and AUC-PR indexes of the method are averagely improved by 8.92%, and the method is remarkably superior to the prior art. The provided Rayleigh quotient purity index provides a quantification tool for spectrum energy distribution analysis, and reveals the strong correlation between frequency selection and spectrum energy.

The invention discloses a zigzag structure-based low-pass high-absorption energy selection surface, which comprises a plurality of periodically distributed units, each unit sequentially comprises a frequency selection layer, a dielectric layer and an energy selection layer from top to bottom, the frequency selection layer comprises a first dielectric substrate and a plurality of metal zigzag structures and resistors on the upper surface and the lower surface of the first dielectric substrate, and the metal zigzag structures and the resistors are arranged on the upper surface and the lower surface of the first dielectric substrate. The selectable layer comprises a second dielectric substrate, and a plurality of metal block structures and diodes on the upper surface of the second dielectric substrate; and the frequency selection layer and the selectable layer are separated by the dielectric layer. The energy selection surface and the frequency selection surface are matched in impedance through the dielectric layer, so that when low-power electromagnetic waves are incident, a low-frequency passband with low insertion loss is realized, and a relatively wide absorption frequency band is formed outside the passband; and when high-power electromagnetic waves are incident, a reflection frequency band with relatively high shielding effectiveness is realized in a working frequency band, and a relatively wide absorption frequency band is formed outside the band. The device is simple and clear in overall design structure principle and has a wide application prospect.

The invention discloses a frequency selective surface unit, an array, a structure and an antenna. The frequency selective surface unit comprises a dielectric plate; the first metal patch comprises a plurality of first extension parts connected with the central part of the dielectric plate, and the plurality of first extension parts extend towards the periphery from the central part of the dielectric plate; the second metal patch comprises a plurality of second extension parts, each second extension part is connected to the tail end of one first extension part, the plurality of second extension parts extend along the edge of the dielectric plate, and the second extension parts are arranged at intervals; wherein the first metal patch and the second metal patch form an LC equivalent resonance circuit. According to the frequency selective surface unit, the array, the structure and the antenna provided by the invention, the frequency response range can be expanded, multi-band electromagnetic waves can be effectively processed, and the performance of the frequency selective surface unit in the aspects of working band, bandwidth coverage, angle stability and the like can be improved.

The present invention relates to the field of high-rate mobile wireless communications. Disclosed are a multi-frequency multi-polarized wide-beam scanning base station system, and an optimization design method. The method comprises: on the basis of an aperture field expansion theory and a mode coupling theory, designing a conical horn feed source antenna capable of radiating a Gaussian fundamental mode beam, and providing a stable beam width and a stable phase center; designing a beam separation device based on a periodic structure, wherein the beam separation device includes band-pass frequency selective surfaces and a linear polarization grid; and combining front-end quasi-optical links of multiple frequency channels and multiple polarized channels, so as to increase the bandwidth and communication rate of a base station antenna. In the present invention, a genetic optimization algorithm is combined with reflector shaping, thereby effectively reducing the conflict between a shielding effect of a dual-reflector antenna and a scanning angle, and realizing the multiplication of a beam scanning angle.

Network Slice Selection Assistance Information (NSSAI) may be signaled between User Equipment (UE) and a network. NSSAI sent from the network to the UE may include, for example, Operating Frequency Band (OFB) for each Single NSSAI (S-NSSAI) in the NSSAI, as well as a Radio Access Technology (RAT) Frequency Selection Priority (RFSP) index, which the network configures as a part of UE access and mobility subscription, during a UE registration procedure. RAT restrictions may be enhanced to indicate to the UE that certain slices are not accessible via certain RATs. A UE may be provided by the network with an alternative NSSAI and corresponding OFBs for each S-NSSAI, thereby indicating to the UE that these S-NSSAI would have been allowed had they been requested. A UE may be able to choose an alternative Allowed NSSAI and send a registration update request to the network.

Systems, methods, and mechanisms to enhance border router performance across Thread, Wi-Fi, and Bluetooth protocols, including mechanisms for Thread network mesh reconfiguration for optimized / enhanced coexistence and frequency selection with Wi-Fi and Bluetooth, co-located Wi-Fi / Bluetooth / Thread coexistence border router design, and dynamic adjustment for Thread energy detection (ED).

Methods, systems, and devices for wireless communications are described. An access point (AP) may update a bitmap (e.g., an extremely high throughput (EHT) operations (Ops) information element (IE) disabled subchannel bitmap) that indicates which channels of a band are available and unavailable. In some examples, the AP may update the bitmap during a channel availability check (CAC) based on whether various channels are DFS channels or non-DFS channels. During the CAC, the AP may transmit beacons to one or more stations (STAs) on the available non-DFS channels (e.g., instead of waiting until after the CAC to perform any beaconing).

The invention discloses a space short wave intelligent frequency selection system and a space short wave intelligent frequency selection method. The system comprises an airborne communication control system, an air-used short-wave radio station, an air-used short-wave antenna and laser inertial navigation equipment. The method comprises the following steps: an air-used short-wave radio station establishes a frequency forecasting model by using a machine learning technology according to time position information; the air-used short-wave radio station obtains a short-wave frequency band available frequency spectrum hole and puts the hole into a sky wave preselected frequency set, and a current passable frequency band is calculated in combination with a frequency forecasting model; the air-used short-wave radio station selects a frequency point with the minimum local electromagnetic interference from the preselected frequency set of the passable frequency band in combination with the local noise distribution condition to perform frequency selection and link establishment; the two parties store and sort the signal-to-noise ratios of the link establishment frequencies, and link establishment is completed if one pair of receiving and transmitting frequencies of the two parties meets communication requirements; and if not, returning to carry out the frequency selection process again until the frequency meeting the communication requirement is selected. According to the invention, automatic intelligent real-time frequency selection is realized, and the efficiency of frequency selection and link establishment and the passability of an air-service short-wave communication system are improved.

The invention discloses a parallel constant-voltage digital audio power amplifier and a broadcasting system. Comprising a line input module, a line output module, a first analog-to-digital conversion circuit, a second analog-to-digital conversion circuit, a third analog-to-digital conversion circuit, a digital signal processor, a single-chip microcomputer, a digital-to-analog conversion circuit, an error comparator, a modulator, an integrating circuit, a pulse width modulation input half-bridge output stage, and a first carrier frequency selection and gain adjustment module. A second carrier frequency selection and gain adjustment module, a first LC filter, a high-frequency compensation network, a communication bus and a power switch. The technical problems that an existing multi-channel parallel digital constant-voltage power amplifier is only limited to power amplifier channels in the same power amplifier, the parallel connection mode only uses the first channel as a main power amplifier and only uses the other channels as slave power amplifiers, and certain limitation exists are solved.