805 results about "Frequency selection" patented technology

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 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.

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 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.

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.

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.

A microwave filter arrangement (100) for quantum computing applications, the filter arrangement (100) comprising a first port (113) and a second port (114). The microwave filter arrangement (100) comprises a main waveguiding structure (110) arranged between the first (113) and second (114) port, where the main waveguiding structure (110) comprises an inner conductor (111) having a circular cross-section that is surrounded by a hollow outer conductor (112) having a rectangular cross-section with two opposed long sides and two opposed short sides. The waveguiding structure (110) comprises a plurality of hollow waveguides (115) extending away from one or both of the long sides of the outer conductor, the hollow waveguides (115) comprising a dielectric material (122) and being terminated by an electromagnetically absorptive material (124).

A broadband low-transmittance and high-absorption wave absorption and transmission integrated frequency selection surface comprises three wave absorption layers and two wave transmission layers which are sequentially stacked from top to bottom, and the three wave absorption layers are sequentially divided into an upper wave absorption layer, a middle wave absorption layer and a lower wave absorption layer from top to bottom; the two wave-transparent layers are sequentially divided into an upper wave-transparent layer and a lower wave-transparent layer from top to bottom; the multi-layer composite structure design is adopted, collaborative optimization of the wave absorbing performance and the wave transmitting performance is achieved by combining the two wave transmitting layers on the lower portion and the three wave absorbing layers on the upper portion, through organic combination of the upper layer structure and the lower layer structure, dual performance improvement of broadband wave absorbing and broadband wave transmitting is achieved, and a transition zone between a wave absorbing zone and a wave transmitting zone is greatly reduced.

The invention provides a continuous time linear equalizer based on a low-pass and band-pass mixed structure. The continuous time linear equalizer comprises a frequency selection coupler, a low-pass transconductance unit, a band-pass transconductance unit and a load unit. The frequency selection coupler is used for separating the differential analog signal into a first voltage component in a first band-pass frequency range and a second voltage component in a low-pass frequency range, the first band-pass frequency range comprises a target frequency expected to be compensated, and the frequency in the first band-pass frequency range is greater than the frequency in the low-pass frequency range; the band-pass transconductance unit is used for converting the first voltage component into current and synchronously realizing gain amplification to obtain a first current signal; the low-pass transconductance unit is used for converting the second voltage component into current and synchronously realizing gain amplification to obtain a second current signal; the load unit is used for summing the first current signal and the second current signal and converting the sum to a differential output voltage signal. According to the invention, the frequency corresponding to the gain peak point and the gain amplitude can be improved.

The invention relates to the technical field of wireless communication, and provides a low-earth-orbit satellite link state management and optimization method, which comprises the following steps of: acquiring communication windows and signal intensities of different low-earth-orbit satellite links by adopting a link prediction method, and further judging whether the satellite links are available or not; when the satellite link is unavailable, a standby satellite is selected in advance, and the optimal switching opportunity is determined; the terminal selects the optimal frequency band for communication in real time according to the current link quality, the satellite signal strength and the interference condition, and dynamically allocates satellite frequency band bandwidth resources by adopting a dynamic frequency selection method; and adjusting a signal modulation mode and a coding rate according to the signal quality. According to the invention, the terminal can select the standby satellite in advance and complete seamless switching before the current link fails, so that the delay and interruption time of link switching are remarkably reduced. The utilization efficiency of spectrum resources is improved by adopting a dynamic frequency selection and bandwidth resource allocation technology, and the anti-interference capability of a communication link in a complex environment is enhanced.

The invention discloses an ultra-wideband RCS (radar cross section) reduction metasurface with mixed wave absorption and diffuse scattering and a wave-transparent window, and belongs to the technical field of electromagnetic metamaterials. The metasurface adopts a four-layer cascade structure and comprises a first layer of polarization conversion structure, a second layer of 2.5 D lossy structure, a third layer of Jerusalem cross-shaped lossy structure and a fourth layer of frequency selective surface structure. By loading a lumped resistor at a specific position and adopting a metal through hole interconnection technology, dual functions of radar cross section reduction in a 1-20GHz ultra-wideband and low insertion loss wave transmission in a 8-12GHz frequency band are realized. The structure of each layer adopts a highly symmetrical design and has the characteristic of polarization insensitivity, and meanwhile, by optimizing interlayer air gaps and dielectric material selection, the structure compactness is realized on the premise of ensuring the performance. The method has important application value in the aspect of integration of stealth equipment and a communication system.

A transmitter system comprises a mapper configured to map data bits and power information to multiple subcarriers, producing mapped information. A first-level modulator converts this mapped information into subcarrier specifications, each defined by a complex number indicating amplitude and phase. The system includes multiple data stream / power channel digital paths, each with a frequency selector that processes a portion of the subcarrier specifications. An orthogonal subcarrier generator translates these specifications from frequency to time domain, generating baseband real and imaginary signals. A second-level modulator processes these signals with intermediate-frequency sine and cosine waves to produce IF I and IF Q signals. A beamformer modifies the phase and / or amplitude of these signals across multiple antenna channels, creating directed signals. Finally, a combiner adds output signals from each data stream / power channel digital path, directing them to corresponding antenna channel modules, facilitating efficient transmission across multiple channels.

The invention provides a narrow-linewidth single-frequency laser frequency stabilization system and method based on a Gaussian filter, and the system employs the Gaussian filter to reduce the optical power of single-frequency laser, and employs the frequency selection characteristic of the Gaussian filter, the frequency spectrum of the single-frequency laser is a single narrow peak, and the frequency stability of the single-frequency laser is improved. When laser frequency passes through a designed Gaussian filter (the fluctuation range of a frequency-stabilized laser source is only on the left side of the center frequency of the Gaussian filter), laser signals can be reduced according to a Gaussian function rule, and along with frequency change, attenuation degrees are different and monotonically change, so that output optical power is different, and the output optical power is changed. And the optical power is compared with the optical power of a preset frequency stabilization target (a half-high point on the left side of a Gaussian filter) to obtain the deviation of the laser source relative to the target frequency stabilization frequency, so that the laser frequency is correspondingly adjusted to achieve the frequency stabilization purpose. The high-sensitivity optical power detection is realized, the response speed and the frequency stabilization precision of the system are improved, and the system is simple in structure and low in maintenance cost.

The invention discloses a broadband low-power-consumption receiving and transmitting shared phase shifter which comprises a differential signal common port, a frequency sampling and control circuit, a dual-mode orthogonal generation circuit and a passive vector modulation synthesis circuit. The differential signal common port comprises a common input / output port interface of RF + and RF-differential radio frequency signals; the frequency sampling and control circuit is composed of a frequency sampling circuit, a frequency detection circuit and a logic control unit. The dual-mode orthogonal generation circuit is composed of a frequency selection change-over switch, a multi-phase filter, a coupling transformer, a matching network 1 and a matching network 2. The passive vector modulation synthesis circuit is composed of two passive vector modulation arrays and two combining / power dividing circuits.

The invention provides a frequency division joint communication method and device based on overlapped multiple beams, and relates to the technical field of satellite communication. Comprising the steps that frequency selection frames forwarded by a communication ground station through satellites are received, the frequency selection frames are all-one sequences after spectrum spreading, and the frequency selection frames of different beams are distinguished through different uplink frequency points; and capturing a frequency selection frame sent by the communication ground station in a frequency selection state, and determining all overlapped beams where the communication terminal is located according to a capturing result. And framing a signal to be transmitted to generate a service frame, and synchronously sending the service frame on the frequency points corresponding to all the determined overlapped beams through multi-beam joint modulation. A multi-beam joint transmission signal is transparently forwarded to a communication ground station through a satellite, so that after the communication ground station separates each beam signal and completes de-spreading operation to obtain symbol-level information, the signals are coherently combined through a cross entropy estimation algorithm, and effective data information is extracted. Multi-beam joint communication is realized, the power spectrum density of the transmitted signal is reduced, and the signal concealment is improved.

The invention relates to the technical field of wireless electric energy transmission, in particular to a wireless charger transmission efficiency optimization method and system, and the method comprises the following steps: collecting frequency current fluctuation, extracting stable frequency, monitoring direction change, switching a transmission path, and improving the transmission efficiency. According to the invention, precision judgment is carried out on the basis of dynamic identification of frequency point fluctuation characteristics, automatic extraction of stable frequency is realized in combination with a fluctuation decreasing trend, time sequence monitoring of main path current polarity change is matched, a section with maximum direction change fluctuation is identified, and a path path is reset in time. The active response capability to an unstable transmission state is improved, the accuracy and timeliness of a path switching condition are enhanced by depending on a dual judgment mechanism of frequency and current data, energy loss caused by abnormal main path direction is effectively reduced, the continuity of a path replacement process and the stability of current output are improved, and the reliability of path switching is improved. And the data closed-loop regulation effect in the frequency selection and path updating process is enhanced.

The invention belongs to the technical field of robot control, discloses a robot end effector force control method and system for conformal vibration polishing of an optical element, and solves the problems of periodic disturbance, friction nonlinearity, multi-axis mutual interference and the like caused by conformal tangential vibration in the polishing process of a complex curved surface of the optical element. And the normal constant force precision, the polishing consistency and the machining surface shape quality are guaranteed. According to the algorithm, a multi-module collaborative architecture is adopted, and means of an observer, adaptive filtering, mutual interference modeling, feedforward friction compensation and the like are combined, so that a set of composite control scheme with high real-time performance, high robustness and good adaptability is formed. High-precision force control under conformal vibration polishing complex disturbance of the robot is achieved; multi-module coordination mechanisms such as a fourth-order extended state observer (4th-ESO), frequency selection filtering and inverse trapped wave compensation, friction feedforward and mutual interference decoupling are introduced;

A multi-band antenna includes a first column of radiating elements that are configured to operate in a first operating frequency band mounted on a reflecting plate; a second column of radiating elements that are configured to operate in a second operating frequency band mounted on the reflecting plate; a first fence and a second fence located on both sides of the reflecting plate that extend forward from the reflecting plate, where the first and second columns of radiating elements are arranged in between the first and second fences, the first fence and the second fence respectively comprise a frequency selective surface with a passband and a stopband, the passband covers at least the first operating frequency band, and the stopband covers at least the second operating frequency band.

The invention provides a metasurface structure and a metasurface structure preparation method, and relates to the technical field of electromagnetic wave regulation and control. The metasurface structure comprises a frequency selection layer, an isolation layer and a reconfigurable gradient impedance layer, the frequency selection layer is located above the isolation layer; wherein the frequency selection layer is used for receiving a first electromagnetic wave incident at a first angle and inhibiting the echo intensity of scattering of the first electromagnetic wave; the reconfigurable gradient impedance layer is located below the isolation layer; wherein the reconfigurable gradient impedance layer is used for receiving a second electromagnetic wave incident at a second angle and inhibiting the echo intensity of scattering of the second electromagnetic wave; wherein the first angle is smaller than the second angle. According to the application, the echo intensity of mirror scattering is suppressed through the frequency selection layer, and the echo intensity of non-mirror scattering is suppressed through the reconfigurable gradient impedance layer, so that electromagnetic scattering suppression of a wide angular domain is realized.

An electronic device may include wireless circuitry with a processor, a transceiver circuit, a front-end module, and an antenna. The front-end module may include amplifier circuitry such as a low noise amplifier for amplifying received radio-frequency signals. The amplifier circuitry may include non-linearity suppression circuitry that suppresses or reduces non-linear behavior of components such as a core amplification transistor and a degeneration inductor within the amplifier circuitry. The non-linearity suppression circuitry may include an intermodulation distortion suppression circuit having an auxiliary amplification transistor. The non-linearity suppression circuitry may include a frequency-selective filter coupled to the degeneration inductor.

The embodiment of the invention provides a design method of a wave-absorbing / wave-transmitting electrically-controlled switchable antenna housing, the structure of the antenna housing comprises an absorbing layer frequency selective surface, a dielectric layer and a wave-transmitting layer frequency selective surface from top to bottom, the absorbing layer frequency selective surface can carry out in-band loss and in-band transmission, the wave-transmitting layer can carry out in-band transmission and out-of-band reflection, and the dielectric layer can carry out in-band transmission and out-of-band reflection. The overall structure interacts to form a radar radome structure integrating absorption and transmission; a microwave network is adopted to carry out impedance analysis on the absorption and transmission radome, parameters are set to represent the characteristics of the microwave network, and meanwhile, a transmission matrix of the microwave network is analyzed through a matrix. The designed antenna housing not only has good out-of-band wave-absorbing stealth performance, but also can switch an in-band wave-transmitting state to a wave-absorbing state through electric control to realize limit stealth.

The invention discloses a predictive complementary frequency selection microwave heating method and a predictive complementary frequency selection microwave heating system. The method comprises the following steps: providing an adjustable frequency in a range of 2.2 GHz to 3GHz by using a solid-state microwave source, and providing various frequency selections for material heating. An efficient frequency set of each heating stage is obtained through multi-physics field modeling, and switching is carried out according to needs in the heating process; meanwhile, the frequency is corrected in combination with experiments so as to make up for the simulation limitation. And determining and applying a corrected frequency sequence according to optimal frequency cycle data predicted by simulation and an energy reflection measurement result of the feed-in port during heating. According to the scheme, under the condition that a complex mechanical structure is not added, through advanced frequency selective heating, the heating uniformity is remarkably improved, hot spots and thermal runaway phenomena are reduced, the heating efficiency and the energy utilization rate are improved, and compared with fixed-frequency heating, heating is more efficient.

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.

The invention provides a broadband absorption and transmission integrated frequency selective surface with a high selection characteristic, which comprises a first loss layer, a second loss layer and a frequency selection layer, and is characterized in that the first loss layer and the second loss layer realize a transmission band with the high selection characteristic and the broadband characteristic at the same time by using dual-order resonance; the second loss layer and the frequency selection layer are cascaded to realize the absorption and transmission integrated characteristic, and the first loss layer is used for improving the low-frequency and high-frequency wave absorption characteristics and expanding the wave absorption bandwidth. Under the combined action of the first loss layer, the second loss layer and the frequency selection layer, wave transmission within the frequency band of 7.72-11.89 GHz and wave absorption within the frequency band of 1.96-7.12 GHz and the frequency band of 12.95-17.33 GHz are achieved. The antenna has high selection characteristics and broadband characteristics, can effectively suppress interference of external electromagnetic waves of other frequency bands or electromagnetic waves of a frequency band close to a communication frequency band on communication, can reduce the radar cross section of a target, and facilitates target stealth.

The invention discloses a new energy box-type substation state abnormity diagnosis method and system, and relates to the technical field of power equipment monitoring. According to the method and the system, through event-triggered high sampling and cross-channel time base self-inspection, multi-source sequence synchronization is ensured, and a consistent time axis is provided for subsequent estimation, so that online analysis under the condition of no power outage is supported; introducing dual-path estimation of RL step fitting and voltage drop robust regression in a transient stage, cooperatively inhibiting a closing peak and outlier data, and obtaining a stable initial value of the contact resistance; in a steady-state stage, adopting Goertzel frequency selection to extract a fundamental wave phasor and performing ohmic purity judgment, and expanding to a resistance-inductance joint model when necessary to remove interference of parasitic inductive reactance on resistance estimation; and then mutual identification and residual constraint are carried out on the temperature and electric power coupling relationship by using a discrete heat RC model, and local write-back correction is carried out on the deviation, so that the consistent closed loop of the electric domain and the heat domain is realized.

The integrated optical structure includes a frequency-selective reflecting structure disposed between a decorative cover layer and an underlying metal layer. The underlying metal layer is configured to reflect and / or absorb radio frequency electromagnetic waves transmitted by the decorative cover layer and the frequency-selective reflecting structures. Each of the frequency-selective reflecting structures includes a frequency-selective surface layer having metal elements arranged on a multilayer stack and repeated across the frequency-selective surface layer to form an array. The integrated optical structure reflects collimated incident RF electromagnetic waves having a wavelength in the range of 1.0 mm to 10 cm and incident at an incident angle at a reflection angle different from the incident angle as collimated reflected waves. For normally incident light having a first visible wavelength, the frequency-selective reflecting structure has an optical transmittance greater than 50%.

The utility model provides a waveguide antenna structure with a frequency selective surface structure and a waveguide radar, and the structure comprises a waveguide antenna which is provided with a waveguide slot array and a frequency selective surface structure; the waveguide slot array is arranged on the waveguide antenna in a penetrating manner, and the frequency selective surface structures are distributed on the peripheral side of the waveguide antenna; the frequency selective surface structure comprises surface structure units, and the frequency selective surface structure is formed by arranging a plurality of surface structure units. According to the utility model, the frequency selective surface structure absorbs reflection between the top surface of the antenna and the antenna housing and reduces distortion of a directional diagram; surface waves can be reduced, space coupling between the antennas is reduced, and the isolation between the antennas is improved; the beam directivity can be adjusted, and beam performance specific directivity can be shaped.

The invention belongs to the technical field of non-magnetic material nondestructive testing, and discloses a non-ferromagnetic material thickness and conductivity synchronous measurement method based on eddy current phase characteristics, and the method comprises the specific steps: S1, estimating the conductivity and thickness range of a to-be-tested piece based on data such as a product specification or an industrial standard; s2, determining excitation frequency according to a frequency selection criterion (high frequency enables the skin effect depth to be smaller than 1 / 3 of the thickness, and low frequency enables the skin effect depth to be larger than two times of the thickness of the sample); s3, an eddy current method is adopted to obtain the impedance variable quantity phase of the to-be-measured non-ferromagnetic material; and S4, substituting the phases into corresponding simplified model formulas respectively, and obtaining the conductivity and the thickness at the same time. Aiming at the problems of multiple calibration, blindness in excitation frequency selection, low single-parameter measurement efficiency and the like in conductivity or thickness measurement by an existing eddy current method, double-parameter output of single measurement is realized, multiple calibration and inversion calculation are not needed, the calculation is simple, rapid and accurate, the hardware cost is low, and the applicability is wide.

The invention belongs to the field of electromagnetic wave absorbing materials, and particularly relates to a thin broadband composite wave absorber based on a frequency selective surface. According to the invention, the wave-transparent layer is added in the middle of the multi-layer magnetic material, the mindset of simply stacking the same type of materials in the traditional multi-layer wave-absorbing structure is broken, and the wave-transparent layer is introduced to change the original characteristic that the impedance gradually changes in sequence; meanwhile, a magnetic wave-absorbing material, a frequency selection surface and a medium matching layer are subjected to composite design, the frequency selection surface generates an electromagnetic coupling effect at high frequency, phase and impedance conversion of electromagnetic waves in a multi-layer structure is controlled, and efficient impedance matching and electromagnetic wave energy dissipation in a broadband are achieved through electromagnetic absorption and interference cancellation; and an excellent wave absorbing effect is achieved. The total thickness of the composite wave absorber ranges from 0.064 lambda to 0.1 lambda, the-10 dB absorption bandwidth ranges from 3.3 GHz to 18 GHz, and the relative bandwidth reaches 138%; and meanwhile, the wave absorber has a wide angular domain characteristic under oblique incidence, and a novel thin broadband composite wave absorber scheme is provided.

Example embodiments relate to frequency selective structures for automotive radar. A system may include a frequency selective structure that is coupled to a radome and configured to optimize a desired band-pass for specific performance by one or more antennas. The frequency selective structure may comprise arrays of micro-wires forming a plurality of intersections and one or more patches positioned at one or more intersections of the plurality of intersections. In some cases, at least one patch of the one or more patches may be positioned with an offset relative to a corresponding intersection of the one or more intersections and the frequency selective structure has a rotational angle with respect to an antenna polarization of the one or more antennas. The frequency selective structure may be connected to a current source that can modify the temperature of the structure to melt rain or snow off the radome.