4911 results about "Broadbanding" patented technology

The invention provides a multi-layer optical film detection method, device and equipment and a storage medium, and the method comprises the steps: obtaining a polarization phase difference signal of transmission light and reflected light through multi-angle incidence irradiation of a multi-band programmable laser source, and recording the polarization ellipticity parameter change; then combining confocal microscopic interference and polarization analysis to determine a space coordinate and a stress distribution diagram of a stress abnormal region; continuously irradiating in a photo-thermal coupling environment through a broadband light source, and monitoring interference signals, polarization states and temperature changes to obtain dynamic evolution characteristics; and finally, performing a simulation test on the multi-layer optical film in a system environment with preset optical axis arrangement and light beam energy distribution, obtaining an in-situ polarization state and interference pattern data, and evaluating the optical performance of the film layer. According to the invention, potential defects can be positioned under high resolution, and the reliability and imaging quality of the film layer under complex application conditions can be accurately evaluated.

The broadband weak current signal detection system comprises a signal acquisition mother board and an upper computer system, the signal acquisition mother board is provided with a signal input interface, a channel switching circuit, a transimpedance amplification circuit, an analog-to-digital conversion circuit, a control core board and the upper computer system, and a three-coaxial BNC interface is adopted. Electromagnetic noise interference in the environment is shielded by a metal noise shielding structure; detecting the switching of a wide measuring range and the switching of an alternating current and direct current coupling mode; weak current signals are converted into measurable voltage signals through a trans-impedance amplifier, and the voltage signals obtained after conditioning are converted into digital quantized values through an analog-to-digital converter (ADC); after being processed by a digital noise reduction algorithm, the data are stored; therefore, the real-time measurement of the broadband weak current signal is realized. The broadband weak current signal detection system has the characteristics of high resolution, good repeatability, high measurement accuracy and good real-time performance, and has good detection capability on weak current signals.

The invention relates to the technical field of power line communication, and discloses a frame synchronization method and device for broadband power line communication, and the method comprises the steps: carrying out the symbolization cross-correlation operation of a received signal, and obtaining a cross-correlation result sequence; performing secondary autocorrelation analysis and accumulation processing on the cross-correlation values in the sequence to generate an autocorrelation accumulated value sequence; screening candidate peak positions according to absolute values of the self-correlation accumulated values; defining a synchronous peak analysis window around the candidate peak position, and setting a noise reference window in an area far away from the window; verifying the validity of the candidate peak based on the difference between the autocorrelation accumulated values of the synchronization peak window and the noise reference window; and if the verification is valid, calculating and determining a final synchronization position through a mean value of a plurality of peak value positions in the synchronization peak window. According to the method, the problem of inaccurate synchronization peak positioning under the multipath effect and noise interference in the existing method is solved through the self-correlation accumulation and noise separation mechanism, and the reliability of frame synchronization is improved.

The invention discloses a converged communication method and system for a satellite broadband ad hoc network, and belongs to the technical field of wireless communication networks, and the method comprises the steps: obtaining a signal quality parameter of a satellite communication link and a distribution density parameter of ad hoc network nodes, and carrying out the feature extraction to generate a network state feature vector; generating a dynamic switching decision instruction in combination with a preset spectrum interference threshold value and a satellite coverage range parameter, executing dynamic switching operation of a satellite link and an ad hoc network link to generate a switching result parameter, performing routing weight distribution on a satellite transmission path and an ad hoc network relay node to generate a fusion routing path, and transmitting the fusion routing path to the ad hoc network. And carrying out priority split charging and encryption compression on the heterogeneous data stream to generate a self-adaptive transmission data packet. According to the method, network state feature vector extraction, dynamic switching decision instruction generation and fusion routing path allocation technologies are adopted, efficient cooperation of satellite and ad hoc network resources can be achieved in a complex electromagnetic environment and a dynamic topology scene, and the communication reliability and the spectrum utilization rate are remarkably improved.

Methods and apparatus are disclosed for assessment of microstructural defects in a large structure. Third order elastic constants engender nonlinear excitation of acoustic modes particularly at points of local stiffness changes or stress concentration such as ends of microcracks. A broadband multimode acoustic signal is transmitted through an interrogation region from a first transducer, whereby a second transducer receives an acoustic signal containing linear and nonlinear components. Linear terms are canceled, and a magnitude of the nonlinear acoustic response is measured using time-resolved spectral analysis, to determine a coefficient for acoustic nonlinearity of the interrogation region that serves as a qualitative or quantitative representation of microcrack damage. Broadband signals avoid mode-specific effects such as shadowing or phase mismatch. Damage location can be identified by region or time-of-flight. Portable or dedicated embodiments can be deployed on a wide range of structures of arbitrary shape.

The invention provides a broadband Doherty power amplification circuit based on a coupler balun active load modulation network, which belongs to the field of radio frequency integrated circuits and comprises an input matching network, a self-adaptive biasing circuit, a main power amplifier, an auxiliary power amplifier and an output matching network. And the output matching network consists of two pairs of differential couplers and a section of 30-degree transmission line, so that the Doherty power amplifier has a broadband active load modulation function. Under a 65-nanometer CMOS (complementary metal-oxide-semiconductor transistor) process, in a working frequency range of 40% of relative bandwidth, the power back-off characteristic is good, and the back-off efficiency is high in a broadband range.

The invention relates to the technical field of broadband spectrums, and discloses a broadband spectrum monitoring system based on dynamic channel allocation, which comprises a data acquisition unit, a data identification unit, a region division unit, a data alignment unit and a channel allocation unit.The system dynamically adjusts the coverage area through beacon nodes, accurately calculates the coverage radius in combination with the urban environment, and improves the coverage efficiency. Meanwhile, a channel allocation strategy is optimized by a game theory, the change of a frequency spectrum environment is responded, and frequency spectrum state parameters are constructed by fusing multi-dimensional characteristics, so that communication smoothness is guaranteed, blind areas of monitoring nodes are eliminated, data space-time alignment is realized, the monitoring sensitivity and the resource utilization rate are effectively improved, and stable frequency spectrum and reliable communication under large-scale activities in cities are ensured; and the dynamic and reasonable distribution of the channels is ensured.

A system can receive a message from a base station configured to communicate via a group of antenna ports, the message being indicative of conducting uplink communications of broadband cellular communications with the base station according to a first group of differing demodulation reference signal densities, wherein respective demodulation reference signal densities of the group of differing demodulation reference signal densities correspond to respective antenna ports of the group of antenna ports, and wherein communicating the broadband cellular communications for uplink communications according to the first group of differing demodulation reference signal densities is performed independently of a second group of demodulation reference signal densities that is configured for downlink communications. The system can use the group of differing demodulation reference signal densities to further communicate the broadband cellular communications with the base station.

The invention discloses a dual-mode analog front end with a full-speed clock-free decision feedback equalizer (UC-DFE). The dual-mode analog front end comprises a terminating impedance matching network, a linear processing link, the UC-DFE and a signal output module, the terminating impedance matching network realizes broadband impedance matching and electrostatic protection; the linear processing link comprises a CTLE and a VGA and is used for compensating channel attenuation and expanding signal bandwidth; the UC-DFE comprises a summator, a static comparator, a delay unit and a feedback tap, and realizes high-speed signal processing and feedback equalization; and the signal output module converts the balanced signal into a target coding format and outputs the signal. According to the invention, the overall performance of the circuit is improved, the problems of time sequence tension, bandwidth limitation and the like of the traditional DFE architecture at a high speed are solved, and the circuit is suitable for 128Gbps high-speed PAM4 and NRZ signal transmission and shows better comprehensive performance.

A system can determine to communicate first broadband cellular communications with a user equipment, wherein the first broadband cellular communications are configured to be communicated via a group of antenna ports, wherein the first broadband cellular communications are for uplink communications according to a first group of differing demodulation reference signal (DM-RS) densities, wherein respective DM-RS densities correspond to respective antenna ports of the group of antenna ports, and wherein communicating the first broadband cellular communications for uplink communications according to the first group of differing DM-RS densities is performed independently of a second group of DM-RS densities that is configured for downlink communications. The system can communicate the first group of differing DM-RS densities for the uplink communications to the user equipment. The system can use the first group of differing DM-RS densities to further communicate the first broadband cellular communications with the user equipment.

The invention discloses a photon-assisted radar frequency shift interference and intermittent sampling forwarding interference integrated signal generation method, and relates to the technical field of microwave photon and radar countermeasure. The method is shown in a figure 1 in the specification and is realized based on a laser device (LD), an arbitrary waveform generator (AWG), a dual-drive Mach-Zehnder modulator (DDMZM), an intensity modulator (IM) and a photoelectric detector (PD). According to the method, by adjusting the period of sawtooth waves, the duty ratio of rectangular pulse signals and the sampling period, generation of interference signals integrating various frequency shift interferences and intermittent sampling and forwarding interferences can be achieved. According to the invention, two simple modulators are adopted, and complex bias voltage and polarization state control is not needed; a digital radio frequency memory is not adopted, analog-to-digital and digital-to-analog conversion is not needed, the real-time performance is good, and parameter tuning is flexible; an electric domain frequency dependent device is not adopted, interference signals with the broadband of more than 1 GHz and the wave band of more than Ku can be generated, and the device is suitable for an electronic countermeasure system with the broadband of more than 1 GHz and the wave band of more than Ku in the future.

The invention provides a covert communication method based on near-field broadband super-large-scale array beam splitting. Comprising the following steps: S1, according to an applied near-field covert communication scene, constructing a corresponding communication model by using a beam splitting effect in a broadband XL-MIMO system, carrying out beam training, and describing a received signal expression of the communication model; s2, constructing a signal detection model of a listener according to a near-field covert communication scene, and describing a detection error probability expression and a covert constraint expression; and step S3, the hidden transmission rate is maximized by optimizing the transmitting power and the subcarrier number of the transmitter. According to the method, the two-dimensional optimization problem related to the transmitting power and the subcarriers is converted into the one-dimensional optimization problem related to the discrete variable quantum carrier number, and the concealment rate of a legal receiver is maximized.

The present invention relates a tunable vibration attenuation device (100) configured to be mounted to a host structure (1) for attenuating vibrations in multiple frequency ranges. The device (100) comprises an auxiliary mass (4) and a shunt piezoelectric system (8) electromechanically coupled between the host structure (1) and the auxiliary mass (4). The shunt piezoelectric system (8) comprising an array of a plurality of piezoelectric devices (2), each connected to at least one shunt circuit (3). Each piezoelectric device (2) being configured to generate electric charge in response to the relative movement of the host structure (1) and the auxiliary mass (4), wherein part of the electric charge is transmitted to at least one shunt circuit (3) of each piezoelectric device (2), and wherein the electrical characteristics of the shunt circuit (3) are adapted to control the oscillatory characteristics of the corresponding piezoelectric devices (2) in one or more vibration frequency ranges of the host structure (1) so as to tune the vibration attenuation device (100) to suppress the host structure vibrations at the desired frequency ranges.

The invention provides a dynamic spreading factor anti-interference method based on annealing Q learning. The method comprises the following steps: determining an information transmission rate according to a spreading factor; determining system throughput and an optimization target according to the signal-to-noise ratio of the receiving end; determining a state space, an action space, a state transition probability matrix and rewards in the decision process; calculating a reward obtained by the selection action according to a broadband spectrum sensing result; the interference condition at the current moment is obtained through broadband spectrum sensing; deciding a spreading factor of the next time slot according to the Q value table; the user selects the action of the next time slot according to the decision information and updates the state; the award obtained by selecting the corresponding action is calculated according to the broadband spectrum sensing result; selecting the spreading factor of the next time slot according to the Q value table, and updating the Q value of the selection action in the state; and the user makes the most anti-interference strategy in a dynamic interference environment. According to the method, the system throughput is maximized, and time delay and overhead caused by channel switching are avoided.

The invention discloses a millimeter wave broadband dual circularly polarized antenna and an array. The millimeter wave broadband dual circularly polarized antenna comprises two layers of microwave medium substrates, a bonding medium, a grounding metal plate and a coaxial feed probe. Two E-shaped patch antennas, four small square patches and an L-shaped metal strip are printed on the upper surface of the upper-layer dielectric substrate, gaps are obliquely formed in the centers of the small square patches, the L-shaped metal strip is used for increasing port isolation, and the E-shaped patches excite the four small square patches to achieve the broadband radiation characteristic. And two coaxial feed probes are respectively connected with two output ends with 90-degree phase difference of the 3dB directional coupler on the lower surface of the lower-layer microwave dielectric substrate, sequentially penetrate through the lower-layer microwave dielectric substrate, the bonding medium, the grounding metal plate and the upper-layer microwave dielectric substrate, and are electrically connected with the two E-shaped patch antennas, so that circularly polarized radiation is realized. According to the invention, the circularly polarized antenna with wide beam width, wide impedance bandwidth, wide axial ratio bandwidth and dual polarization characteristics is realized, and the circularly polarized antenna is suitable for potential application requirements of millimeter wave frequency band wireless communication and satellite communication.

The broadband dual-polarization magnetoelectric dipole antenna comprises a first dielectric layer and a second dielectric layer arranged below the first dielectric layer, and the first dielectric layer and the second dielectric layer are connected through a bonding layer to serve as an antenna substrate for supporting a magnetoelectric dipole unit. The magnetoelectric dipole unit comprises metal patches and magnetic dipoles, the metal patches and the magnetic dipoles are used as electric dipoles and magnetic dipoles, the magnetic dipoles penetrate through the first dielectric layer and are arranged on the lower side of the second dielectric layer, and the four metal patches are annularly and uniformly arranged on the upper side face of the first dielectric layer; the shape of the metal patch is a rectangle with semi-elliptical chamfers on two side edges of the outer edge; any metal patch is coupled with two gain patches arranged on the first dielectric layer, and the gain patches are circular. The problem that in the prior art, a magnetoelectric dipole antenna is poor in impedance bandwidth capacity, and therefore the requirement of people for the network information transmission speed cannot be met is solved.

According to the broadband single-layer dual-polarization microstrip antenna, a radiation patch and a short-circuit metal column are combined to form an EBG structure, and the working bandwidth is greatly improved. And the two ports are connected with the circular parasitic patch through the coaxial line, so that radiation energy coupling is realized, and impedance matching is improved. And two ports are orthogonally arranged, so that the isolation is improved. The four slits suppress the coupling current between the adjacent antenna units, an additional decoupling structure is not needed, the polarization purity is ensured, and the cross polarization is less than-15dB. The antenna is compact in structure, a single-layer substrate is adopted, the profile of the antenna is 0.08 working wavelength, miniaturization, dual polarization, broadband and high isolation are achieved, processing is simple, the antenna works in the 16.7 GHz Ku frequency band, and the-10 dB impedance bandwidth is about 16%. According to the invention, a miniaturized, dual-polarized, broadband, high-isolation and monopole-like radiation mode is realized, the radiation mode is stable, and the antenna can be used as a phased array unit.

The invention discloses a broadband wide frequency spectrum analysis method and system based on deep learning. The method comprises the steps of spectrum signal acquisition, spectrum preprocessing, abnormal interference detection, spectrum trend prediction and spectrum scheduling management. The invention relates to the technical field of wide-frequency spectrum analysis, in particular to a broadband wide-frequency spectrum analysis method and system based on deep learning, which adopts a three-step method of abnormal interference detection, spectrum trend prediction and spectrum scheduling management, and adopts a layer-by-layer progressive deep learning and reinforcement learning technology. The real-time detection of spectrum abnormity, the accurate prediction of future trend and the optimal allocation of dynamic resources can be realized; carrying out abnormal interference detection by adopting a joint improvement multi-classification support vector machine method combined with feature enhancement; performing spectrum trend prediction by adopting a time sequence integrated network combined with one-dimensional convolution feature extraction; and performing spectrum scheduling management by adopting a reinforcement learning method enhanced by a near-end strategy optimization algorithm.

The invention discloses a transformer on-line monitoring and fault early warning system, and particularly relates to the technical field of power equipment monitoring, and the system comprises a signal collection module, a signal filtering module, a broadband focusing module, a signal complexity analysis module, a threshold self-tuning module, a fault early warning module and a fault positioning module. The signal acquisition module acquires operation data of a transformer in real time through a sensor network, the filtering module removes noise, and the broadband focusing module converts broadband signals into narrow-band signals, so that the resolution is improved; the signal complexity analysis module evaluates the signal complexity, and the threshold value self-tuning module dynamically adjusts the threshold value; the fault early warning module judges whether to trigger early warning based on the adjusted threshold value, and the fault positioning module determines the position of the partial discharge source through a cross positioning algorithm; according to the invention, the problem that the accuracy of early warning is affected due to the fact that a traditional fixed-threshold monitoring method is easy to generate false alarm or missing alarm can be solved, and operation and maintenance personnel can be helped to quickly determine the position of a fault source through cross positioning.

The invention provides a broadband tunable low-phase-noise photo-generated microwave signal source and device, and relates to the technical field of photo-generated microwaves. According to the invention, a low-frequency optical pulse and a high-frequency microwave signal are respectively input into the electro-optical sampling phase-locked loop; and the electro-optical sampling phase-locked loop determines the synchronization error of the optical pulse and the microwave signal based on the phase difference between the optical pulse center point and the microwave signal zero crossing point. And taking the synchronization error as a feedback signal, and continuously adjusting the frequency and the phase of the microwave signal by the voltage-controlled oscillation module until the frequency and the phase are synchronized with the Nth harmonic of the optical pulse. By setting different initial frequencies of the voltage-controlled oscillation module, microwave signals with different integral multiple optical pulse frequencies can be obtained, and broadband tuning of photo-generated microwave signals is realized. Furthermore, the repetition frequency of the frequency comb is locked through beat frequency of two beams of reference laser and two adjacent comb teeth, the stability of the reference laser is transmitted to the optical pulse, and the stability of the reference laser is further transmitted to the microwave signal through synchronization of the optical pulse and the microwave signal, so that the phase noise of the photo-generated microwave signal source is reduced.

The invention belongs to the technical field of electromagnetic signal monitoring and analysis, and particularly relates to a multi-dimensional multi-channel broadband signal monitoring platform and an amplitude phase testing method.The monitoring platform is composed of a plurality of eight-channel receiving single machines, eight receiving single machines serve as a group, and any one of the eight receiving single machines serves as a basic function single machine in each group; a synchronous reference signal is generated through a parallel synchronous reference correction processor built in each functional single machine, and n * 8 parallel signals are received. The amplitude and phase test method comprises a frequency domain amplitude and phase consistency test and a time domain amplitude and phase consistency test. According to the invention, a synchronization reference rule correction processing mechanism and a frequency, amplitude and phase correction module are constructed, so that the technical problems that a long-term stability synchronization test cannot be realized only by adopting a step-by-step single-channel test in a traditional test, radio frequency phase shift introduced by a multi-channel synchronization test is inconsistent with an acquisition time sequence and the like are solved; and the signal parallel receiving and consistency analysis capabilities of 8 * n channels are realized.

The invention discloses a broadband lightning very high frequency radiation source positioning method based on an ESPRIT algorithm, and the method comprises the steps: 1, constructing an orthogonal uniform linear very high frequency antenna array, and collecting broadband lightning very high frequency signals; 2, discrete Fourier transform is carried out on the broadband thunder and lightning very-high-frequency signals, the broadband thunder and lightning very-high-frequency signals are divided into J frequency points, and the frequency domain value of each frequency point signal is worked out; step 3, dividing the orthogonal uniform linear very high frequency antenna array into two sub-arrays in an x-axis direction and a y-axis direction, positioning each frequency point value of the signals in the two directions by using an ESPRIT algorithm, and respectively obtaining a calculation incident angle of each frequency point in the two directions; step 4, carrying out phase ambiguity resolution on the calculated incident angles of each frequency point in the two directions so as to obtain a real incident angle; and 5, calculating the azimuth angle and the elevation angle of the radiation source according to the real incident angle. According to the invention, rapid and refined positioning imaging of the lightning radiation source can be realized.

The invention discloses a broadband low-coupling dual-polarization dielectric resonator antenna based on dual-mode resonance and differential feed. The broadband low-coupling dual-polarization dielectric resonator antenna comprises a dielectric resonator, two pairs of orthogonal coaxial probe pairs, a first Wilkinson power divider, a second Wilkinson power divider, a first feed port and a second feed port, the two pairs of orthogonal coaxial probes are both inserted into the dielectric resonator; each pair of coaxial probes is connected with two output ends of the corresponding Wilkinson power divider; the first feed port excites the pair of coaxial probes to feed the dielectric resonator through the first Wilkinson power divider, and excites a horizontal polarization radiation mode in the x-axis direction; a second feed port excites the other pair of coaxial probes to feed towards the dielectric resonator through a second Wilkinson power divider, and a horizontal polarization radiation mode in the y-axis direction is excited; according to the invention, a dual-polarization radiation mode which is compact in structure, broadband and low in coupling is realized, and each polarization further increases the bandwidth by exciting two resonance modes with close frequency points.

The invention provides a K-band broadband dual circularly polarized antenna applied to the satellite internet, and belongs to the field of circularly polarized antennae, the K-band broadband dual circularly polarized antenna comprises a radiation unit, a first dielectric layer, a metal ground layer, a bonding layer, a second dielectric layer and a feed network which are stacked from top to bottom, the radiation unit comprises two first radiation patches and two second radiation patches, the first radiation patch is provided with two long rectangular grooves which are vertically intersected, the second radiation patch is provided with two short rectangular grooves which are vertically not intersected, the first radiation patch and the second radiation patch are respectively connected to the metal ground layer through metal columns, and the metal ground layer is provided with a first coupling gap and a second coupling gap. A first rectangular groove, a second rectangular groove, a third rectangular groove and a fourth rectangular groove are formed in the metal ground layer, and the feeder network comprises a first microstrip feeder and a second microstrip feeder; the antenna structure is low in profile, wide impedance bandwidth can be achieved, and the two feed ports can work in the same frequency range.

The invention relates to a thin cloth rectangular plane broadband array antenna synthesis method, and belongs to the technical field of array antenna optimization. The method comprises the following steps: firstly, establishing a mathematical model of a rectangular plane broadband array antenna, initializing parameters of the broadband array antenna, and performing sparse processing on a full array by using a Kaiser weighting function; secondly, initializing a sparse array position population by adopting Tent chaotic mapping, calculating an array element to generate a population fitness function value, and recording an optimal individual; thirdly, adopting an improved grey wolf optimization algorithm to carry out sparse optimization on the sparse array, calculating an updated array element fitness value, extracting an optimal fitness value, recording a corresponding array element position, and outputting an optimal array element position arraying scheme; and finally, obtaining a frequency invariance directional diagram with a smaller side lobe based on the SRV constraint of infinite norm. According to the invention, the number of antenna array elements can be effectively reduced, the frequency-invariant wave beam of the minimum side lobe is realized, and the cost of an antenna system is reduced while the performance of the broadband array antenna is ensured.

An on-chip mid-infrared micro-ring resonant cavity microfluidic spectrometer is integrated on a substrate material and comprises a spot size converter, an optical coupler, a microfluidic module, a micro-ring resonant cavity, a miniature thin-film resistance heater, a sequential control power supply module, an optical filtering system and a photoelectric detector array. Selective filtering is performed on an input optical signal, and the flow and flow velocity of liquid or gas to be detected are controlled by using the microfluidic module, so that selective absorption of spectral components of the liquid or gas to be detected is realized. In addition, the invention also discloses a mid-infrared integrated optical chip micro-fluidic multiphase detection device comprising the spectrometer and a detection method thereof, the device also comprises a pumping and reference light source module and an on-chip mid-infrared frequency comb generation module, a broadband frequency comb is generated as a light source, a photoelectric detector array is used for collecting signals, and the detection precision is improved. The detection and inversion of the type and concentration of multi-component liquid or gas to be detected are realized, and the on-chip, real-time and micro detection of multi-component substances is realized.

The invention discloses a dual-frequency / broadband switchable dynamic tuning metamaterial terahertz absorber which comprises M * N terahertz absorption units of a multi-layer structure, the M * N terahertz absorption units of the multi-layer structure are distributed in an M * N two-dimensional mode, and M and N are positive integers. Each terahertz absorption unit with the multi-layer structure comprises a metal substrate, a dielectric layer and a resonance layer which are sequentially arranged from bottom to top; the dielectric layer and the metal substrate are square and have the same side length; the resonance layer comprises a single-layer graphene layer with a hollow cross, and a solid cross-shaped vanadium dioxide layer is embedded in the hollow part of the single-layer graphene layer with the hollow cross; and the appearance of the single-layer graphene layer with the hollow cross is cross-shaped. The absorber can be dynamically tuned, has the characteristic of polarization insensitivity, and can keep stable absorption in an incidence angle range of 0-60 degrees. The invention further discloses a preparation method of the dual-frequency / broadband switchable dynamic tuning metamaterial terahertz absorber.

The embodiment of the invention relates to the technical field of wireless communication, in particular to a low-overhead multipoint time-frequency positioning method based on a federated learning framework, which comprises the following steps: establishing a broadband cognitive network system model, and selecting a time-frequency positioning model; the central server initializes network parameters of the time-frequency positioning model and issues the network parameters to each secondary user; a secondary user carries out local training on a local time-frequency positioning model based on a local data set, determines the weight of a subnet model, then extracts the gradient variation of each BN layer, carries out sorting based on the gradient variation, carries out dynamic pruning on the local time-frequency positioning model according to a target pruning rate, obtains a model mask, and uploads the model mask to a central server; and the central server complements the model by using each model mask, aggregates each subnet model weight to obtain a global weight, forms a personalized subnet model of each secondary user, and issues the personalized subnet model, thereby realizing low-overhead multi-point time-frequency positioning. According to the method, the communication overhead of the wireless link is effectively reduced, and the communication efficiency is greatly improved.

The invention provides a multifunctional satellite-borne integrated radio frequency system and device. The multifunctional satellite-borne integrated radio frequency system comprises a broadband low-profile integrated transceiver array, a reconfigurable integrated radio frequency front end and a flexible high-performance processing platform, the broadband low-profile integrated transceiving array adopts a multi-subarray design, has the capabilities of multi-beam signal transceiving, two-dimensional wide-angle beam scanning and received signal low-noise amplification, and adopts a low-profile and foldable structural design to adapt to the constraint of a satellite-borne platform; the reconfigurable integrated radio frequency front end has the capabilities of full-band signal up-down conversion processing and multi-channel full-interaction radio frequency routing; the flexible high-performance processing platform adopts a reconfigurable, open-type and high-reliability digital processing architecture, and has the functions of intermediate-frequency signal high-speed sampling, high-performance digital processing, software definition and on-orbit dynamic upgrading. According to the invention, a traditional discrete satellite-borne radio frequency system can be converted into a high-integration, multifunctional and conformal system, and the scale of the satellite-borne radio frequency system can be effectively reduced.

The invention discloses a broadband scattering beam reconfigurable low RCS planar array antenna. The antenna array structurally comprises a metal radiation oscillator structure, a dielectric substrate, an offset line structure, a rectangular metal floor, a pin header, a slotted metal aluminum plate and a feed structure from top to bottom, the pin header penetrates through the dielectric substrate; the metal radiation array structure realizes phase regulation of the antenna unit on reflected electromagnetic waves and regulates the beam direction of scattered electromagnetic waves; the antenna array is composed of N * N antenna units, and N is greater than or equal to 2 and is a positive integer. According to the invention, broadband scattering phase reconstruction is realized, and the wide radiation characteristic of the antenna is realized by using the tight coupling design.