392 results about "Frequency selectivity" patented technology

The embodiment of the invention relates to the technical field of remote sensing image processing, and provides a panchromatic sharpening method and device for a satellite remote sensing image, electronic equipment and a medium, and the method comprises the steps: obtaining a to-be-processed satellite remote sensing image in a panchromatic mode and a multispectral mode; performing up-sampling processing on the multispectral modal image until the target output size of the target panchromatic sharpening image is reached, and obtaining a multispectral modal first satellite remote sensing image; performing multi-scale feature extraction on the panchromatic modal image to obtain different scale features of the panchromatic modal satellite remote sensing image; performing frequency selectivity enhancement processing on image features of the first satellite remote sensing image and the panchromatic modal image with the same scale as the first satellite remote sensing image to obtain high-frequency features and low-frequency features with different scales; and carrying out feature fusion on the high and low frequency features with the same scale, and carrying out image reconstruction to obtain a target panchromatic sharpening image. Therefore, the detail richness and the visual coordination of the reconstructed image can be improved.

The invention discloses a bionic TENG sensor unit for an artificial throat and a preparation method thereof, and relates to the field of artificial throats, and the sensor unit comprises a gradient micro-dome friction layer, a strain amplification layer, an electrode layer and a back cavity substrate layer. The gradient micro-dome array realizes gradual contact through gradient change of height and diameter; the strain amplification layer converts vertical vibration into horizontal strain by using a cantilever beam-sliding block structure; the back cavity array selectively amplifies vibration at a specific frequency based on the Helmholtz resonance principle. The invention further provides a corresponding preparation method. The preparation method comprises the steps of back cavity forming, electrode deposition, microstructure manufacturing, surface treatment and the like. The sensor has the advantages of high sensitivity, good frequency selectivity and strong durability, and is particularly suitable for detecting weak laryngeal vibration signals of laryngeal patients.

The invention discloses an OCT (Optical Coherence Tomography) retina image denoising method based on a high-frequency enhanced diffusion model, which is characterized in that a double-branch diffusion model network constructed based on frequency perception Fourier transform attention (FFTA) is used for separating different frequency domains, enhancing specific frequency domain features and fusing the specific frequency domain features into a spatial domain feature map to realize stronger frequency domain perception and processing capability; the invention relates to a time step T coding method for a module of frequency domain attention. The time step T of the diffusion model is used as a parameter to be coded into a frequency domain attention module to participate in self-attention matrix calculation, so that frequency domain feature processing is aligned with the iteration step number of the diffusion model, and different frequency domain information is pointedly processed at different time steps T; the frequency selective hopping mechanism uses pooling operation to obtain a high / low frequency characteristic pattern, so that the network has adaptive frequency domain retention capability for different local parts.

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 filtering patch antenna with out-of-band high suppression and high frequency selectivity. Comprising a dielectric substrate, a radiation patch printed on the front surface of the dielectric substrate, a parasitic branch knot, an air layer, a metal ground, a feed circular hole etched in the metal ground and used for separating a feed short needle from a metal ground plane, the feed short needle inserted into the dielectric substrate, and nylon columns inserted into four corners of the dielectric substrate and the metal ground plane and used for fixing. The structure is simple and compact, the working bandwidth is widened, the out-of-band rejection capability and the frequency selectivity are remarkably enhanced, and the requirement for coexistence of multiple frequency bands is met.

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.

This application describes multi-band antenna systems and base stations. An example multi-band antenna system includes: a plurality of radiating element arrays, feeding networks separately corresponding to the plurality of radiating element arrays, at least one layer of a frequency selective surface (FSS), and a reflection panel. The plurality of radiating element arrays are located above the reflection panel. All or some of the plurality of radiating element arrays are stacked. The at least one layer of the FSS is located between the stacked radiating element arrays. A feeding network corresponding to at least one radiating element array in the stacked radiating element arrays is electrically connected to the at least one layer of the FSS, or the feeding network corresponding to the at least one radiating element array is integrated on the at least one layer of the FSS.

The invention provides an electric connector signal transmission optimization method and system, and relates to the technical field of communication, and the method comprises the steps: obtaining an electrical characteristic parameter and transmission path topological information, recognizing a frequency turning point, calculating a loss coefficient, constructing a frequency selectivity compensation mapping rule, and obtaining a frequency division compensation strategy; and calculating a double-component correction factor, carrying out nonlinear adaptive adjustment to obtain a target compensation parameter, and finally generating a multi-path compensation control signal. According to the invention, loss characteristics in signal transmission can be accurately identified, frequency selective compensation is realized, and the signal transmission quality and stability of the electric connector are improved.

The disclosure deals with system and method for discerning the radius maximizing reliability for binary modulation on conjugate-reciprocal zeros (BMOCZ) implemented with both a maximum likelihood (ML) and direct zero-testing (DiZeT) decoder. The optimal radius for BMOCZ is disclosed to be a function of the employed decoder. The radius maximizing the minimum distance between polynomial zeros does not maximize the minimum distance of the final code. While maximizing zero separation offers an almost optimal solution for the DiZeT decoder, the ML decoder outperforms the DiZeT decoder in both additive white Gaussian noise (AWGN) and fading channels when the radius is chosen to maximize codeword separation. Different sequence-to-subcarrier mappings for BMOCZ-based orthogonal frequency division multiplexing (OFDM) are analyzed to highlight a flexible time-frequency mapping approach that avoids distortion introduced by a frequency-selective channel at the expense of higher peak-to-average power ratio (PAPR).

The embodiment of the invention provides a tunable cavity filtering coupler, an antenna device and communication equipment, and relates to the technical field of mobile communication. The tunable cavity filtering coupler comprises a dielectric substrate, a base layer and a metal layer arranged on the surface of at least one side of the base layer, the metal layer is provided with an annular coupler and a bias circuit, the annular coupler comprises four center loading branch resonators which are sequentially distributed in the circumferential direction, and the four center loading branch resonators are connected with the bias circuit. Each center loading branch resonator is connected with a variable capacitance diode. The metal layer further comprises feed ports which are in one-to-one correspondence with the center loading branch resonators and are connected with the center loading branch resonators. The biasing circuit is arranged on the periphery of the annular coupler in a surrounding mode, and the biasing circuit is electrically connected with the variable capacitance diode. According to the tunable cavity filtering coupler, the antenna device and the communication equipment provided by the invention, frequency selectivity and passband tunable functions are realized, and multi-band operation requirements are met.

The present invention discloses a UAV communication system, including a UAV end, a ground end, a communication link sending module and a communication link receiving module. The communication link sending module is used to carry TB on channel time-frequency resources and send it to the communication link receiving module according to a preset resource allocation scheme; the communication link receiving module is used to distinguish different TBs and different copies of TBs, and screen according to two TB indication fields in the correctly received TBs to obtain valid data contained in the TBs. The present invention carries the transmission blocks to be repeatedly sent on the redundant channel resources of the UAV communication link, and sends copies of the same TB on channel resources with different frequencies and / or different times to obtain the effect of additional frequency diversity gain and / or time diversity gain, compensating for the adverse effects of the frequency selective fading and / or time selective fading characteristics of the wireless channel on the correct reception of the signal, so as to achieve the purpose of making full use of the available channel resources to improve the quality and reliability of link data transmission.

The invention discloses a broadband millimeter wave magnetoelectric dipole filtering antenna unit and a filtering array, the antenna is realized by adopting a multi-layer printed circuit board, and the antenna comprises a radiation layer printed circuit board and a feed layer printed circuit board. The radiation layer printed circuit board is provided with a magnetoelectric dipole radiator, and an electric dipole patch etched with an H-shaped gap reduces the size of the radiator while achieving low-frequency good filtering. A substrate integrated waveguide (SIW) cavity is arranged around the magnetoelectric dipole radiator, so that surface waves are suppressed, and the overall suppression effect of a stop band is enhanced. A strip line fed by a coaxial probe and a shielding SIW cavity structure are integrated on a feed layer printed circuit board, and the feed structure generates two radiation zero points at high frequency, so that good filtering response is realized. The antenna provided by the invention has the advantages of wide frequency band, small size, high out-of-band rejection level and frequency selectivity.

The invention relates to the technical field of electromagnetic fields and microwaves, in particular to a high-order dual-band band-pass frequency selective surface, which comprises an upper metal layer, a dielectric substrate and a lower metal layer, and is characterized in that the dielectric substrate is arranged between the upper metal layer and the lower metal layer; a large rectangular ring gap and four small rectangular ring gaps are etched on the upper metal layer and the lower metal layer respectively, the four small rectangular ring gaps are located on the four edges of the large rectangular ring gap, and four small rectangular metal patches, a large rectangular metal patch and irregular peripheral metal patches are adopted after etching. According to the invention, the overall performance of the frequency selective surface can be enhanced, so that the frequency selective surface shows more excellent selectivity and stability in multi-band application.

The invention discloses a broadband intelligent metasurface, and the metasurface is characterized in that the left part and the right part of a metal radiation patch are respectively and additionally provided with an open rectangular ring metal groove, and the two added open rectangular ring metal grooves are symmetrically arranged in the metal radiation patch in a manner that the openings face inwards; in this way, a new resonance mode with the frequency of f4 is introduced into the two open rectangular ring metal grooves in the off state of the intelligent metasurface unit, so that the phase shift range of the intelligent metasurface unit is expanded, and the phase bandwidth of the intelligent metasurface unit is increased. Compared with a traditional intelligent metasurface, the broadband intelligent metasurface has a wider working bandwidth, improves the channel capacity of a communication system, supports a higher data transmission rate, and better resists multipath interference and frequency selective fading, thereby improving the reliability of signals and the communication quality. According to the broadband intelligent metasurface, broadband electromagnetic signals can be regulated and controlled at the same time through one metasurface, and the design and deployment cost of the intelligent metasurface can be effectively saved in application deployment.

The invention discloses a three-dimensional water-based frequency selective absorber with convertible electromagnetic performance. The three-dimensional water-based frequency selective absorber comprises a plurality of symmetrical three-dimensional gradient structure dielectric square waveguide frequency selective surface unit structures and periodic water-based metamaterial absorber units, the three-dimensional gradient structure dielectric square waveguide frequency selective surface unit structure has broadband transmission performance with high frequency selectivity. The periodic water-based metamaterial absorber unit is packaged around the frequency selective surface unit structure and has ultra-wideband absorption performance; three transmission poles and two transmission zero points are generated by cascading three metal square rings up and down in the three-dimensional gradient structure dielectric square waveguide frequency selective surface unit structure, so that a high-frequency-selectivity broadband band-pass three-dimensional frequency selective surface is realized; by controlling the on-off of water in the periodic water-based metamaterial absorber unit, the conversion of transmission band external absorption and reflection electromagnetic characteristics is realized. According to the invention, the transmission bandwidth is expanded, the absorption frequency band is wide, the absorption rate is high, and dual polarization can be realized.

In a probabilistic amplitude shaping (PAS) system, a distribution matching (DM) component may receive a uniform bit sequence with equal probabilities, which may be converted into symbols with a desired probability distribution (e.g., Gaussian). For example, the probability distribution may use inner constellation points associated with a lower energy and / or power more frequently and outer constellation points associated with a higher energy and / or power less frequently. In general, the DM component may map binary bits to positive amplitudes with a non-uniform distribution according to a DM rate that is based at least in part on a signal-to-noise ratio (SNR), which may vary significantly in a spatial and frequency selective wireless channel. Accordingly, some aspects described herein relate to configuring DM parameters and codeword and resource mappings in a spatial and frequency selective wireless channel.

The invention discloses an elastic wave filter based on an annular cylindrical shell thin plate structure and an implementation method thereof. The elastic wave filter comprises a homogeneous elastic thin plate and a resonance structure of a hollow annular cylindrical shell. By introducing an annular cylindrical shell resonance structure, efficient filtering and frequency selective control of elastic waves are realized. The filter has the advantages of high frequency selectivity, wide bandwidth control, construction flexibility, high reliability and the like, and is suitable for the fields of signal processing, sensing and the like.

The invention discloses a wide-stop-band reflection-free double-frequency filter, particularly relates to the technical field of microwave communication, and solves the problems that in the prior art, a double-frequency-band filter usually has signal reflection outside a working frequency band, and a small number of reflection-free double-frequency-band or multi-frequency-band filters are often complex in structure and low in cost. The technical problems of large size, poor absorption effect and poor high-stop-band effect of a non-reflection dual-band filter in the prior art, and certain out-of-band rejection performance and insertion loss are sacrificed while the non-reflection dual-band filter pursues the non-reflection characteristic, and particularly, harmonic suppression is poor in a transition area of two frequency bands and a high-stop-band area are solved. According to the technical scheme, a quarter-wavelength coupling microstrip line MCL1 and a quarter-wavelength microstrip line ML2 are connected in series, and a three-quarter-wavelength microstrip line ML1 and a three-quarter-wavelength microstrip line ML2 are introduced and connected in parallel to form a dual-frequency band-pass filtering response; according to the invention, a good full-band absorption effect is achieved, and the frequency selectivity of in-band signals is also enhanced.

A lossy dielectric heat source transducer or other transducer can be formed using a multi-layer substrate, such as can include a power layer (to receive an applied electromagnetic input signal), a polyurethane or other polymeric electromagnetic energy absorption layer, and a coupling layer therebetween. The absorption layer can be doped with carbon or another dopant material to increase electromagnetic energy absorption. The coupling layer can be doped with barium titanate or another dopant material to focus electromagnetic energy passing through the coupling layer toward the absorption layer. Frequency-selective addressing of particular transducers can include using a plurality of planar resonators, which can be configured to resonate at the same or different specified frequencies of the applied electromagnetic input. Such addressing of such frequency-sensitive structures can permit location-specific actuation of one or more transducers.

The invention relates to a method for rapidly turning off a pulsed light cavity ring-down system light source based on frequency shift keying, belongs to the technical field of cavity ring-down spectroscopy, and aims to couple laser generated by a laser light source into a ring-down cavity and realize the function of rapidly and conveniently turning off an optical signal coupled into the ring-down cavity by utilizing the frequency selectivity of the ring-down cavity and combining the frequency shift keying technology. An oscilloscope is used for observing and recording a ring-down signal, when a detection signal reaches a set trigger threshold value, a positive pulse trigger signal is output to a signal generator to start frequency shift keying, and the frequency of incident light is modulated, so that a light source coupled into a ring-down cavity is cut off. According to the invention, an extra circuit control plate is not needed to turn off the current of the laser driver, and a solution is provided for rapidly turning off the laser source in the pulsed cavity ring-down technology.

The invention discloses a terahertz detector based on a circular metasurface and graphene composite structure and a method, and belongs to the technical field of semiconductor devices and micro-nano machining. The device comprises a substrate, a graphene layer, a circular metasurface layer, a first electrode and a second electrode, the graphene layer is arranged on the substrate; the first electrode and the second electrode are oppositely arranged on two side ends of the graphene layer; the circular metasurface layer is arranged on the graphene layer and located between the first electrode and the second electrode. According to the invention, the local field enhancement effect of the metasurface structure is combined with the photoelectric response of graphene, the frequency selective absorption of terahertz waves is realized, the signal-to-noise ratio and selectivity of the detector are improved, and the sensitivity and response speed of the detector are improved at the same time.

The invention provides a component high-frequency signal transmission quality prediction and optimization method and system, and relates to the technical field of signal transmission, and the method comprises the steps: extracting the attenuation change rate of each frequency band based on the frequency domain characteristics and transmission path physical characteristic parameters of a to-be-transmitted signal of a component, and building a correlation function with a frequency band boundary position; calculating a transmission path terminal prediction loss spectrum and determining a compensation gain coefficient; performing frequency selective amplitude adjustment on the to-be-transmitted signal; and an actual received signal is collected and compared with the target frequency domain amplitude distribution, and the correlation function is updated. According to the invention, accurate prediction and adaptive optimization of high-frequency signal transmission quality are realized, and signal transmission integrity is improved.

The invention discloses a channel prediction method and device suitable for a non-ground network, and relates to the technical field of artificial intelligence, and the method comprises the steps: S1, user equipment located on the ground carries out uplink communication with a gNodeB located on an LEO satellite; s2, the CP-OFDM waveform carrying the resource grid is sent by the user equipment and is propagated through a frequency selective channel; s3, at a receiving end, removing the cyclic prefix from the signal, and performing demultiplexing on the received symbol; and S4, for the estimation value of the CFR matrix, applying least square channel estimation on the received pilot symbol, and performing interpolation in the time slot duration. According to the channel prediction method and device suitable for the non-ground network, channel estimation can be not affected by removing pilot frequency every other OFDM time slot, the uplink peak throughput can be remarkably improved regardless of the data modulation order in most cases, and the performance is hardly affected.

A tuned-frequency-spectrum earpiece for selectively tuning audio frequencies that enter an inner ear of a user wearing the earpiece, the earpiece including a base having an emitter end and receiver end, the base including a channel that passes through an entirety of the base; a sound-attenuation plug, wherein the sound-attenuation plug is configured to couple to the base such that the sound-attenuation plug surrounds at least a portion of the channel of the base; a first filter device configured to insert into the channel of the base and to selectively reject undesired frequencies of the audio frequencies that enter the earpiece; and a frequency-selective sound collector operatively coupled to the receiver end of the base and configured to increase an amount of desired frequencies of the audio frequencies that enter the first filter device. Some embodiments increase the amount of sound from some directions while reducing sound from other directions.

The invention discloses a time-frequency domain joint channel equalization method for a single-carrier NOMA (Non-Orthogonal Multiple Access) system, and solves the problems that a single carrier is poor in frequency selective fading resistance and is not matched with NOMA power multiplexing signals in the prior art. The method comprises the following steps of: at a receiving end of a single-carrier NOMA system, converting a received signal of each frame into a frequency domain by using FFT (Fast Fourier Transform), and carrying out data separation to obtain a section of unique word sequence and an effective data sequence; estimating channel state information in a frequency domain by utilizing prior information and a section of unique word sequence to obtain a channel estimation result corresponding to each symbol, and performing minimum mean square error frequency domain equalization on a section of effective data sequence according to the result to obtain a corresponding frequency domain signal; performing fine adjustment on the corresponding frequency domain signal in the time domain by using a time domain soft decision equalization algorithm of the power distribution factor to obtain an equalized time domain signal; according to the method, more accurate channel compensation is realized, and the decoding performance and the anti-interference capability of the system are improved.

A frequency selective unit, a frequency selective surface, and an antenna base station. The frequency selective unit comprises a metal reflector plate and at least two conductive material pattern layers, wherein through holes are provided in the metal reflector plate, the at least two conductive material pattern layers run through the through holes, and there is a gap between the conductive material pattern layers and the metal reflector plate; and at least one conductive material pattern layer comprises a first transmission mode, and at least the other conductive material pattern layer comprises a second transmission mode, and in a transition band, electromagnetic waves in the two transmission modes have opposite phases and cancel each other, such that the electromagnetic waves cannot be transmitted through the frequency selective unit; moreover, an electromagnetic wave transmission zero can be generated in the transition band, and a sharp roll-off is formed at an out-of-band edge of a second band, thereby realizing high-frequency selectivity. The conductive material pattern layers are not parallel to the metal reflector plate, the transmission direction of the electromagnetic waves is parallel to the surfaces of the conductive material pattern layers, and it is not necessary to provide a metallized via hole between the at least two conductive material pattern layers to perform electrical connection, thereby simplifying the manufacturing process and processing difficulty of the frequency selective unit.

Described is a frequency selective limiter (FSL) module comprising a cascade of an FSL and a functional limiter (e.g. a conventional semiconductor limiter comprising a PIN diode) with steady state limiting and power threshold values selected such the FSL module provides suppression of a spike leakage power and while still enabling frequency selective limiting.

The invention discloses a space-time modulation filtering circulator based on a substrate integrated waveguide, which consists of a top metal patch, a dielectric substrate, a bottom metal floor, a large metalized through hole and a small metalized through hole, and comprises a rectangular SIW cavity I, a rectangular SIW cavity II, a rectangular SIW cavity III, a pentagonal SIW cavity I, a pentagonal SIW cavity II, a pentagonal SIW cavity III and a circulator central junction, the rectangular SIW cavities are traditional SIW cavities resonating in a fundamental mode, and the pentagonal SIW cavities are space-time modulation SIW cavities; the pentagonal SIW cavity I, the pentagonal SIW cavity II and the pentagonal SIW cavity III are coupled and cascaded through a circulator central junction; the rectangular SIW cavities I, II and III are cascaded with the pentagonal SIW cavities I, II and III in a magnetic coupling mode; the rectangular SIW cavity I, the rectangular SIW cavity II and the rectangular SIW cavity III are fed by the coplanar waveguide transmission line I, the coplanar waveguide transmission line II and the coplanar waveguide transmission line III; according to the space-time modulation SIW filtering circulator provided by the invention, ferrite materials are not needed, the circulator function is realized by adopting three tuning elements, the design complexity of the space-time modulation circulator is reduced, and the frequency selectivity is improved.

The invention discloses a low-profile low-RCS (radar cross section) circular polarization double-folded transmission array antenna, which comprises a wave-absorbing type frequency selection polarizer and a double-folded transmission array antenna, and is characterized in that the wave-absorbing type frequency selection polarizer is positioned above the double-folded transmission array antenna; the wave-absorbing type frequency selection polarizer comprises a loss layer and a linear circular polarization converter with a frequency selection characteristic, wherein the loss layer and the linear circular polarization converter are separated by an air gap layer; the double-folded transmission array antenna comprises an integrated reflection-transmission metasurface and a polarization conversion metasurface, and the integrated reflection-transmission metasurface and the polarization conversion metasurface are separated by an air gap layer. According to the circularly polarized antenna, the single-station RCS reduction performance of more than 10 dB is achieved within the broadband range of 6.8-21.9 GHz, meanwhile, the radiation gain can be improved, the profile can be reduced, and the circularly polarized antenna has the advantages of being wide in band, low in profile, high in gain and low in RCS.