301 results about "Out of band rejection" patented technology

A tunable duplexer circuit is described, wherein the frequency response as well as bandwidth and transmission loss characteristics can be dynamically altered, providing improved performance for transceiver front-end applications. The rate of roll-off of the frequency response can be adjusted to improve performance when used in duplexer applications. A method is described where the duplexer circuit characteristics are optimized in conjunction with a specific antenna frequency response to provide additional out-of-band rejection in a communication system. Dynamic optimization of both the duplexer circuit and an active antenna system is described to provide improved out-of-band rejection when implemented in RF front-end circuits of communication systems. Other features and embodiments are described in the following detailed descriptions.

A hyper-spectral imaging filter has serial stages along an optical signal path in a Solc filter configuration. Angularly distributed retarder elements of equal birefringence are stacked in each stage, with a polarizer between stages. The retarders can include tunable (such as abutted liquid crystals tuned in unison), fixed and/or combined tunable and fixed birefringences. Although the retardations are equal within each stage, distinctly different retardations are used for two or more different stages. This causes some stages to pass narrow bandpass peaks and other stages to have widely spaced bandpass peaks. The transmission functions of the serial stages are superimposed with selected preferably-tunable peaks coinciding. The resulting conjugate filter has a high finesse ratio, and good out of band rejection.

A system for a wireless communication infrastructure using single crystal devices. The wireless system can include a controller coupled to a power source, a signal processing module, and a plurality of transceiver modules. Each of the transceiver modules includes a transmit module configured on a transmit path and a receive module configured on a receive path. The transmit modules each include at least a transmit filter having one or more filter devices, while the receive modules each include at least a receive filter. Each of these filter devices includes a single crystal acoustic resonator device with at least a first electrode material, a single crystal material, and a second electrode material. Wireless infrastructures using the present single crystal technology perform better in high power density applications, enable higher out of band rejection (OOBR), and achieve higher linearity as well.

The present invention provides a multilayer substrate integration waveguide filter with high out-of-band rejection. The problems are solved that the size of the current substrate integration waveguide is large, the level of the out-of-band rejection is not high, and the loss is still large. The filter comprises in order from up to down comprises a first metal layer (1), a first dielectric layer (2), a second metal layer (3), a second dielectric layer (4) and a third metal layer (5) which are stacked. The materials of the first metal layer (1), the second metal layer (3) and the third metal layer (5) are copper or sliver or tin or the composite layer formed by two types of metal mentioned above, namely the substrate metal is plated with another metal layer, and the first dielectric layer (2) and the second dielectric layer (4) can be common high-frequency circuit substrate and also can be the substrate though LTCC sintering or a semiconductor substrate. The multilayer substrate integration waveguide filter with the high out-of-band rejection can be configured to allow a transmit-receive front end to filter interference signals, and is good in the out-of-band rejection, small in loss and small in size.

The invention relates to a broadband multichannel channelization system and an implementation method based on an optical frequency shift, and belongs to the technical field of microwave photonics. Aninterference effect between electrooptical modulators and the optical frequency shift characteristic are utilized, and multi-channel division and high-rejection ratio same-intermediate-frequency frequency conversion of broadband microwave signals are completed. The invention proposes the broadband multi-channel channelization method based on the optical frequency shift by combining optical frequency shift channelization and I/Q down-conversion. According to the broadband multi-channel channelization method provided by the invention, a single-frequency laser is combined with a double-sided bandfrequency shift to complete the channel division of a broadband signal; and the output of several two-way same-intermediate-frequency signals which are mirrored to each other through the I/Q down-conversion is realized, which not only avoids the defect that light filtering out-of-band rejection capability is poor in traditional channelized receiving, but also avoids the defect that high-quality coherent optical comb implementation is complex in channelized receiving based on an optical frequency comb.

A tuned resonator circuit topology is disclosed that permits implementation of narrow band-pass filters having high loaded Q and optimal coupling (for low insertion loss) using a parallel tuned resonator topology at frequencies in the 1 to 2 GHz range and beyond. The topology consists of a mirror image of the parallel tuned circuit about the signal line of a conventional parallel tuned circuit to effect a cancellation of virtually all of the induced currents between the inductive elements of the resonators. This reduction in induced currents reduces the magnetic coupling between the resonators, thereby offsetting the increase in overall coupling between the resonators as frequency increases, and thereby serves to maintain optimal coupling between the resonators as the frequency of operation increases. Moreover, the mirror image topology increases the parallelism between the inductive elements in the resonators, thereby decreasing the inductance values and permitting an increase in capacitance values. Increasing the capacitance values of the resonators effectively offsets the decrease in the loaded Q as frequency is increased. The topology works for any number of parallel resonators. As the resolution of the manufacturing process decreases (e.g. from printed circuit board to integrated circuit processes), the range of operating frequencies scales with the increase in resolution.

The invention relates to a hybrid lumped distribution miniature band-pass filter. The hybrid lumped distribution miniature band-pass filter comprises a 50-ohmage input-output port installed on the surface, four parallel-connection resonance units, two interstage coupling inductors, a interstage coupling capacitor, a Z-shaped cross coupling capacitor and an input/output inductor which are all achieved through the multilayer low-temperature co-fired ceramic technical skill. The hybrid lumped distribution miniature band-pass filter has the advantages of being good in band-pass selectivity and out of band rejection, low in insertion loss, light in weight, small in volume, high in reliability, good in electric performance, phase-frequency characteristic linearity, temperature stability and electric performance batch uniformity, low in cost, capable of being produced massively and the like, and is especially applicable to radars, communication, rocket carrying, plane carrying, missile carrying, spacecrafts, man-portable mobile communication terminals and other wireless communication handheld and portable terminal products and corresponding frequency range systems with strict requirements for volume, weight, electric performance, reliability and the like.

The invention belongs to the technical field of functional materials and specifically relates to a high temperature-resistant frequency selective surface (FSS) wave-transparent material and a preparation method thereof. A high temperature-resistant ceramic matrix is taken as a carrier of the high temperature-resistant FSS wave-transparent material and an FSS with a resonant structure is attached onto the surface of the high temperature-resistant ceramic matrix. The FSS is directly prepared on the ceramic matrix by use of a high temperature-resistant conducting material, has the high temperature resistance in contrast with a flexible film FSS and is capable of meeting the hiding requirement of an antenna housing during high-Mach flying. The high temperature-resistant FSS wave-transparent material is a compound material of a plurality of layers of FSSs; due to the design of size and shape parameters of the resonant structure of the FSS, the frequency bandwidth and the transmittance of incident electromagnetic waves can be effectively controlled, and a hiding effect with in-band high transmittance and out-of-band rejection can be realized.

The invention relates to a frequency selective surface structure with wide passband and ultra-wide stopband. The frequency selective surface structure comprises a fine square ring array layer, a spiral meander line array layer and a thick square ring array layer, wherein the fine square ring array layer is etched on an upper surface inner side dielectric plate, the spiral meander line array layer is etched on an intermediate metal layer lower side dielectric plate, the thick square ring array layer is etched on a lower surface outer side dielectric plate, an upper side foam material interlayer is further arranged between the upper surface inner side dielectric plate and the intermediate metal layer lower side dielectric plate, and a lower side foam material interlayer is further arranged between the intermediate metal layer lower side dielectric plate and the lower surface outer side dielectric plate. The frequency selective surface structure has the advantages of small unit size, small thickness, low transmission loss, wide passband, good out-of-band rejection, further has the beneficial effects of ultra-wide stopband, wide electromagnetic wave scanning angular domain and stable scanning along azimuth angle of frequency response, and can be widely applied to antenna housing design in platforms such as radars, satellite communication and aircrafts.

The invention discloses a cavity filter. The cavity filer comprises a metal cavity and a metal cover plate which is positioned on the metal cavity, wherein the metal cavity comprises at least eight resonance cavities which are coupled in sequence; a resonance rod is arranged in each resonance cavity; and the resonance rods in the first and the last resonance cavities are connected with an input signal connector and an output signal connector respectively. The coupling between the adjacent resonance cavities is magnetic coupling; coupling windows and coupling rods are arranged between the corresponding resonance cavities on the left and right sides of a passband; four places of crossed coupling is introduced, so that two transmission zero points can be generated on the left and right sides of the passband respectively, and higher out-of-band rejection can be achieved; the outline dimension of the overall filter cavity is not changed; the order of the filter is not increased, and the size of the filter is not enlarged; meanwhile, the cavity filter is easy to process and debug, and low in cost; and the large-batch production of the cavity filter can be achieved.

The invention discloses a broadband dual-polarization base station filter antenna unit without an external filter circuit and an array thereof. The antenna unit is arranged in the middle of the reflector. The antenna comprises an oscillator arm, a balun and two parasitic metal rings. The vibrator arm is provided with a microstrip line branch, is connected through the balun, and is fed through thebalun, and the balun is provided with a feeder line. The upper part and the lower part of the vibrator arm are respectively provided with parasitic metal rings. The antenna unit has the characteristics of compact and simple structure. The invention realizes good out-of-band rejection effect and has good frequency selectivity without cascading filter, thus avoiding filter insertion loss. The invention realizes high polarization isolation, and realizes stable pattern in wide frequency band at the same time.

The invention discloses a design and preparation method for a cavity type FBAR (thin-film bulk acoustic resonator) filter. The method comprises the following steps: an FBAR ladder filter based on a Mason model is simulated with ADS (Advanced Design System) software, and physical parameters of each film layer whose transmission performance meets index requirements for insertion loss and out-of-band rejection are obtained; a piezoelectric layer in corresponding thickness and a composite film layer of an electrode layer grow on a preparation substrate, a support substrate is taken additionally for forming cavities, the composite film layer is bonded with the support substrate, the original preparation substrate is stripped off, upper electrode layers with different thicknesses grow, and an electrode/piezoelectric layer/electrode/cavity composite structure is formed. Parameters of the upper electrode film layer on the FBAR filter designed and prepared with the method are controlled precisely, and the performance of the obtained filter is excellent; damage probably caused by introduction of a sacrificial layer and adoption of a chemical mechanical polishing method to a resonance structure in the traditional technology is avoided, and device loss is reduced.

The invention discloses an electrically tunable four-passband filter based on a double layered resonator, and mainly solves the problems that the number of passbands of a traditional electrically tunable filter is small, adjustable passband bandwidth is not constant, the out-of-band rejection degree is poor and the volume is large. The electrically tunable four-passband filter based on the double layered resonator includes a pair of parallel coupling feeder lines (1) and a pair of adjustable stepped impedance resonators (2, 3) which are arranged on an upper microstrip medium substrate (7), and a branch loading resonator (4) and two direct current biasing circuits (5, 6) which are arranged on a lower microstrip medium substrate (8), wherein the two direct current biasing circuits (5, 6) are connected to two ends of the adjustable stepped impedance resonators (2) and (3), thereby realizing continuously adjustability of a third passband and a fourth passband, and the branch loading resonator (4) realizes fixing of a first passband and a second passband. The electrically tunable four-passband filter based on the double layered resonator is small in size and high in out-of-band rejection degree, can realize four passbands, realizes continuous adjustability of the third passband and the fourth passband under the condition that the bandwidth is basically maintained unchanged, and can be used for a wireless communication system.

The invention discloses an aperture multi-layer structure-based high-out-of-band rejection frequency selective material design method. The method includes the following steps that: (1) a frequency selective material is designed based on an aperture multi-layer structure, wherein the aperture multi-layer structure includes three layers of structures, namely, a top-layer patch, a bottom-layer patch and a middle coupled aperture layer; (2) an out-of-band transmission null characteristic is realized through constructing a design method of patch displacement of the top-layer patch and the bottom-layer patch, and the side band cut-off characteristic of the aperture multi-layer structure-based frequency selective material can be further improved; and (3) a unit interdigital technology is adopted to carry out miniaturization processing on the surface of the frequency selective material, so that the unit size of the surface of the frequency selective material can be decreased. With the method of the invention adopted, a high-order coupling characteristic is realized, and the side band cut-off performance of the frequency selective material can be improved; and the unit interdigital method is adopted, so that the unit size of the surface of the frequency selective material can be decreased, and angle stability under the incoming of electromagnetic waves can be improved; and the out-of-band rejection ability of the frequency selective material is stronger, and the pass-band edge rise performance and sharp drop performance of the frequency selective material are better.

The invention relates to a band-pass filter. The band-pass filter comprises a resonator as well as an input feeder line and output feeder line which are arranged on the resonator; a first folded slot line, a connecting slot line and a second folded slot line of the resonator form a first resonant structure; and a first folded portion and a second folded portion of the resonator form a second resonant structure. The resonator provided with a coplaner stepped impedence resonator structure and a folded slot line resonator structure is designed, and therefore, the filter has the advantages of simple and compact structure, excellent selectivity, strong high-frequency out-of-band rejection and the like. Two or three such band-pass filters can be connected in cascade, so that a fourth-order band-pass filter and a sixth-order band-pass filter having excellent selectivity and strong high-frequency out-of-band rejection can be designed easily.

The invention provides a multi-layer complementary structure terahertz band-pass filter based on a frequency selective surface, and belongs to the technical field of electromagnetic wave transmission function devices. The filter comprises an underlay dielectric substrate and two frequency selective surface layers which are arranged on upper and lower surfaces of the underlay dielectric substrate; the two frequency selective surface layers are arranged oppositely with the same structure; each frequency selective surface layer comprises N*N resonance units arranged in a matrix, and N is more than or equal to 30. The filter is high in Q value, small in insert loss, flat in passband ripple, remarkable in out-of-band rejection, simple in structure and small in size, and is convenient to adjust and control and easy to process.

The invention relates to a radio-frequency power amplifier linearization system based on a broadband modulator. The system comprises a receiving device, a channel and an emitting device. The emitting device at least comprises a test data generation device, a predistortion device, a modulation device and a power amplification device. The receiving device at least comprises a synchronous demodulation device, a data recovery device and a predistortion parameter calculation device. According to the predistortion parameter calculation device, a predistortion coefficient vector A is acquired by the optimized variable step size LMS algorithm, and the predistortion device is configured through the acquired coefficient. After an emitted signal matrix U passes the predistortion device, the predistortion device output vector Z is acquired by that Z = UA. According to the system, on the basis that the original LMS algorithm is not modified, the segment interval is refined and the step size is replaced, the step size factors of the LMS algorithm are corrected, the predistorted out-of-band rejection is increased by about 3dB and is closer to the optimal coefficient, and the nonlinear predistortion compensation effect is improved.

Narrow band tunable radio frequency (RF) power amplifiers (PAs) and related methods are disclosed that provide narrow band tunable gain responses, such as linear gain responses, that can be selected for different frequency bands. The narrow band tunable PAs thereby provide out-of-band rejection for different selectable frequency bands so that narrow band filters are not required in the transmit input path for communication devices. The passband location and/or bandwidth for the narrow band gain response can be tuned using different techniques, as desired. The narrow band tunable PAs can also be fabricated using CMOS processing, if desired, so that a CMOS PA integrated circuit is provided.

The invention discloses a waveguide filter based on electromagnetically induced transparency. The waveguide filter comprises an upper cavity, a lower cavity, a medium substrate, a signal input port and a signal output port, wherein the upper cavity and the lower cavity form a standard rectangular waveguide, and the medium substrate is inserted into the portion between the upper cavity and the lower cavity of the standard rectangular waveguide. A rectangular metal ring, an out-of-band rejection sheet, two rows of metallized through holes and a grounding epitaxial band are arranged in a metal micro-strip structure on the front face of the medium substrate, and two symmetric C-shaped resonance structures and a grounding epitaxial band are arranged on a metal micro-strip structure on the back face of the medium substrate. The rectangular metal ring located on the front side of the medium substrate and the two symmetric C-shaped resonance structures located on the back face of the medium substrate interact to generate a passing band of an electrically induced transparent window and a passing band of a magnetically induced transparent window, namely, the electromagnetically induced transparency effect is formed, upper sidebands and lower sidebands of the passing bands of the waveguide filter obtained through the effect are respectively provided with a transmission zero, high selectivity is achieved, and the waveguide filter is compact in structure and easy to design.

The embodiment of the invention discloses a filter coupling structure with adjustable capacity. The filter coupling structure is arranged in a cavity with at least two resonant cavities. The filter coupling structure contains a coupling structure which is arranged between the resonant cavities and contains a plastic part and a metal sheet, wherein a part of the metal sheet is embedded in the plastic part, two opposite projection parts extend from the two sides of the center of the metal sheet; the projection parts are embedded in the plastic part; a first adjusting screw rod penetrates a cover plate, and the cover plate are matched with the cavity; and the first adjusting screw rod is arranged between the two opposite projection parts. The invention provides a simple and realizable filterwhich is easy to form and the filter coupling structure with adjustable capacity which can be adjusted without being disassembled and have wide adjusting range, so as to satisfy the demand of the out-of-band rejection degree.

The invention provides a broadband combiner, which comprises a circuit board, wherein at least one combiner unit is arranged on the circuit board, is provided with an input end and an output end, and comprises a first filter and a second filter; an input port of the first filter is a first input port, and an input port of the second filter is a second input port; the first and second input ports are arranged back to back and axially distributed; signals of different frequency bands are input from the first and second input ports, and are filtered and synthesized for output through the output end of the combiner unit; the output end is arranged on one side of the first and second input ports. The broadband microstrip line combiner is small in size and high in out-of-band rejection performance, third-order intermodulation and power capacity, and has a broader working frequency band, as well as relatively lower return loss and insertion loss within the working frequency band, the design cost is reduced, and a larger space is provided for deployment of another feed network to facilitate assembling.

The invention proposes a filter dielectric resonator antenna with a double-radiation zero value. The problems of surface wave loss and ohmic loss of an existing filter patch antenna are mainly solved.The filter dielectric resonator antenna comprises a dielectric substrate (3), a metal floor (4), a micro-strip feeder (5) and a short-circuit via hole (6). The metal floor and the micro-strip feederare printed on the upper surface and the lower surface of the dielectric substrate, and a feed structure is formed by connection through a short-circuit via hole: a second dielectric plate (2) and a first dielectric block (1) are fixed in sequence to the upper part of the metal floor, the first dielectric block acts as a radiator, and the second dielectric plate achieves good matching between theradiator and the feed structure; and two stepped slits (7) and (8) of the same size are engraved on the surface of the metal floor and used for slot coupling feeding to avoid the influence of parasitic radiation. The filter dielectric resonator antenna has good out-of-band rejection capability while maintaining high gain, the surface wave loss is avoided, the antenna radiation efficiency is improved, and the wireless signal can be received and transmitted in a C-band.