267results about How to "Improve out-of-band rejection performance" patented technology

The band-pass filter has a stacked pair of film bulk acoustic resonators (FBARs) and an acoustic decoupler between the FBARs. Each of the FBARs has opposed planar electrodes and a layer of piezoelectric material between the electrodes. The acoustic decoupler controls the coupling of acoustic energy between the FBARs. Specifically, the acoustic decoupler couples less acoustic energy between the FBARs than would be coupled by direct contact between the FBARs. The reduced acoustic coupling gives the band-pass filter desirable in-band and out-of-band properties.

The band-pass filter has an upper film bulk acoustic resonator (FBAR), an upper FBAR stacked on the lower FBAR, and, between the FBARs, an acoustic decoupler comprising a layer of acoustic decoupling material. Each of the FBARs has opposed planar electrodes and a piezoelectric element between the electrodes. The acoustic decoupler controls the coupling of acoustic energy between the FBARs. Specifically, the acoustic decoupler couples less acoustic energy between the FBARs than would be coupled by direct contact between the FBARs. The reduced acoustic coupling gives the band-pass filter desirable in-band and out-of-band properties.

A thin film bulk acoustic wave (BAW) resonator structure and filter which can be fabricated by inexpensive manufacturing techniques and in smaller size than conventional such products are to be provided. The BAW resonator structure and filter have a substrate, a first BAW resonator placed over the substrate, an acoustic reflection layer placed over the first BAW resonator and a second BAW resonator placed over the acoustic reflection layer, and the acoustic reflection layer is electroconductive. Herein, the acoustic reflection layer constitutes a first electrode, and this first electrode electrically connects and acoustically separates the first BAW resonator and the second BAW resonator.

The invention relates to a microstrip bandpass filter with a sector open-circuit structure, belonging to the technical field of microwave/millimeter wave devices and relating to a microwave/millimeter wave integrated circuit. Based on a traditional parallel coupling microstrip line filter, the microstrip bandpass filter with the sector open-circuit structure adds two sections of sector open-circuit shunts; either sector open-circuited shunt is a one-fourth wavelength terminal open-circuit line with a sector-structure end terminal; and the start terminals of the two sections of sector open-circuit shunts are perpendicularly connected with a center point of an auxiliary microstrip line. The invention has the advantages of simple form, compact structure and high beyond-strip attenuation, not only can be used in a microwave/millimeter wave integrated circuit, but also can be used in a submillimeter wave band with higher frequency. Meanwhile, an input microstrip line and an output microstrip line of the microstrip bandpass filter with the sector open-circuit structure are on the same straight line, thereby facilitating the application in practical projects.

A filter for electromagnetic radiation including one or more dielectric spacer regions and one or more reflective regions integrated on a semiconductor substrate, the semiconductor substrate including a semiconductor photodetector, such that the filter transmits ultraviolet radiation to the semiconductor photodetector, the ultraviolet radiation having a range of wavelengths, and the filter suppresses transmission of electromagnetic radiation, having wavelengths outside the range of wavelengths, to the semiconductor photodetector.

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 broadband dual-polarized filtering dipole antenna without an additional circuit, which is characterized in that two pairs of mutually perpendicular radiation array sub-arms are printed on a horizontal dielectric substrate, and the two pairs of mutually perpendicular radiation array sub-arms are horizontally placed; two vertical dielectric substrates are respectively equipped with baluns to feed the radiation array sub-arms, and the balun includes a slot line, two closed stubs and an inverted L-shaped feeder line with the tail end being open-circuited; the two vertically intersecting vertical dielectric substrates are arranged on a reflecting plate; the closed stubs are close to the middle position of the vertical dielectric substrates on the top and connected withthe radiation array sub-arms on the horizontal dielectric substrate through extending upwards so as to constitute a short-circuit inverted L-shaped resonator together; and the horizontally placed radiation array sub-arms and the part which does not extend upward at the top of each closed stub constitute resonant groove together. The invention realizes a broadband filtering antenna operating at 1.7-2.8GHz, and has the excellent performance such as high isolation, weak cross polarization and good filtering and radiation characteristics.

The invention discloses an ultra-wideband band-pass filter with a transmission zero point, and aims to provide a band-pass filter with the excellent trapped wave characteristic and standing wave performance. The ultra-wideband band-pass filter with the transmission zero point is realized by the following technical scheme that dumbbell rectangle heads of two symmetric air bridges restricted betweenmetal ground passbands are symmetrically etched on the wide edges of the left and right sides of each of the front and back surfaces of a dielectric substrate, the first dumbbell head located at theproximal end of the wide edge of the dielectric substrate forms an equivalent circuit of a first resonator and lumped parameters of the first resonator in a manner that a first high-impedance short-circuit branch is vertically connected with a first low-impedance open-circuit branch of a terminal, and the second dumbbell head located at the far end of the wide edge of the dielectric substrate forms an equivalent circuit of a second resonator with a dual relationship with the first resonator and lumped parameters of the second resonator; and an equivalent circuit of a third resonator and lumpedparameters of the third resonator, composed of an H-shaped branch, falls in a cup-shaped cross section formed by synthesizing two flag shapes oppositely and symmetrically, wherein the first resonatorsequentially transmits signals to the second resonator and the third resonator to form a main transmission link path.

The invention belongs to the technical field of microwaves and millimeter waves and provides a dual-mode reconfigurable filter based on a half-mode substrate integrated waveguide and a CSR structure,mainly to solve the problems that an ordinary tunable filter has large insertion loss and bias voltage of a PIN diode can not be directly added to the substrate integrated waveguide. The half-mode substrate integrated waveguide technology is adopted, an upper metal pattern layer comprises a half-mode substrate integrated waveguide copper clad layer, a DC bias circuit, an epsilon-type microstrip line and other structures. Two complementary circular spiral resonators (CSR) are arranged at two sides of the copper clad layer, through applying forward/reverse bias voltage, the PIN diode is conducted or cut off, the upper metal copper and the epsilon-type microstrip line are conducted or cut off, and finally, single dual passband switching is realized. The reconfigurable filter under the features is particularly suitable for a wireless communication system, and has the advantages of small size, low insertion loss, multiple transmission zero points, high out-of-band suppression, convenient DCfeed loading, quick tuning speed, convenient tuning and the like.

Provided is a dielectric waveguide filter with a defected ground loaded on a magnetic coupling structure. A row of metallized through holes is punched in each of two sides of a dielectric substrate, electromagnetic waves are limited to be spread in an area between the upper and lower metal surfaces of the dielectric substrate and the two rows of metallized through holes, and a dielectric waveguide transmission line is formed; two pairs of left-right symmetrical metallized through holes are formed in the formed dielectric waveguide transmission line and are perpendicular to the horizontal center line, the dielectric waveguide transmission line is divided into three parts which form dielectric waveguide resonant cavities, and the two pairs of left-right symmetrical metallized through holes form the magnetic coupling structure; double L-shaped transition structures are loaded from an input/output microstrip line to the upper layer metal surface of the dielectric waveguide transmission line to form transition from the microstrip line to the dielectric waveguide, and meanwhile a defected ground structure is loaded on the lower layer metal surface of the dielectric waveguide resonant cavities adjacent to the double L-shaped transition structures. The dielectric waveguide filter has the advantages of low insertion loss and high out-of-band rejection, and can be applied to fields such as the radio frequency front end, image rejection and spurious suppression.

The invention relates to a differential microstrip filter antenna fed by a balun filter. The structure uses a balun filter to generate the differential signal with filtering characteristics, which excites the differential fed microstrip antenna, and realizes the miniaturized differential fed microstrip antenna with filtering and radiation characteristics at the same time. The filter antenna has stable gain in the pass band, fast gain drop out of the pass band and good edge selectivity. In addition, the radiation pattern of the structure is symmetrical and the cross polarization can achieve -35dB. on both the E plane and the H plane.

The invention relates to a high out-of-band rejection trans-impedance amplifier, suitable to be used but not be limited in a down-conversion mixer circuit of a software radio transceiver. The trans-impedance amplifier comprises a first differential operational amplifier (101), a second differential operational amplifier (102), capacitors (111, 112, 113, 114, 151, 152), and resistors (121, 122, 131, 132, 141, 142). The normal phase output end of the first differential operational amplifier is connected with the inverted input end of the second differential operational amplifier through the resistors. The inverted output end of the first differential operational amplifier is connected with the normal phase input end of the second differential operational amplifier through the resistors. Two ends of the capacitor (151) are connected with the normal phase input end and the inverted input end of the first differential operational amplifier (101). Two ends of the capacitor (152) are connected with the normal phase input end and the inverted input end of the second differential operational amplifier (102). Through respectively adding the capacitors on the input ends of the differential operational amplifier (101, 102), improvement of out-of-band rejection of the trans-impedance amplifier is realized.

The invention discloses a TE102 mode CT structure terahertz cross coupling waveguide filter, and belongs to the technical field of terahertz. According to the filter, based on a conventional CT structure, a TE102 mode is employed, and transmission zeros can be generated at a low terminal of a stop band. The filter comprises transitions, rectangular resonant cavities, and coupling diaphragms, the filter is divided into three layers based on the vertical direction, and each layer can avoid the generation of an island structure. According to the filter, cross coupling is realized in the terahertz frequency band, the structure is simple and novel, the echo loss in a passband is low, the insert loss is low, the suppression performance of the stop band is good, and the filter is especially applicable to the SU-8 equal-dividing layer thick-film process for processing.

The invention relates to a maritime ultra-short wave beyond visual range communication device, and belongs to the technical field of the communication device. The device is composed of a radio frequency receiving unit, a radio frequency transmitting unit, a baseband unit and so on. The device is characterized in that an antenna is connected with the radio frequency transmitting unit and the radio frequency receiving unit through an electronic switch. The radio frequency transmitting unit and the radio frequency receiving unit are connected with the baseband unit. The radio frequency transmitting unit is composed of an excitation module and a power module. The radio frequency receiving unit is composed of a radio frequency front end module, a frequency conversion module, an intermediate frequency amplification unit and an intermediate processing module. The baseband unit is composed of a DSP digital signal processing unit, an FPGA field-programmable gate array module. The device has the advantages that the noise coefficient is low, the sensitivity is high, the dynamic range is wide, the low signal to noise ratio demodulation is accurate, the multi-path interference of remote communication can be reduced, the maritime beyond visual range communication distance is long, the communication quality is good, and the existing problems that the multi-path interference of the remote transmission is serious, the noise interference is high, the beyond visual range communication cannot be realized, and the maritime beyond visual range communication quality is influenced are solved.

A wideband bandpass filter includes an RF input terminal, an RF output terminal, a plurality of electrically tunable coupling capacitors coupled in series between the RF input and output terminals, and a plurality of resonating circuits each including an electrically tunable resonator capacitor coupled to one of the coupling capacitors. At least one resistance is coupled in series between at least one of the coupling capacitors for providing enhanced out of band rejection of the filter.

The invention provides a broad-stopband electrically-tunable dual-frequency band-pass filter comprising a metal microstrip line in the front, a dielectric board layer, a first input/output port, a second input/output port, ground metal vias and a metal coating arranged on the back of the dielectric board layer. The metal microstrip line in the front is composed of a uniform impedance resonator, a short-circuited stub and an input/output coupling line; a variable capacitance diode is loaded between the uniform impedance resonator and the short-circuit stub, forming a tunable structure; the tail end of the short-circuited stub is grounded through the ground metal vias. The broad-stopband electrically-tunable dual-frequency band-pass filter is compact in structure, allows dual-frequency tunable, is low in band-pass internal insertion loss and good in out-of-band rejection and has broad stopband.

The ultra-wide-band filter serves as a key unit in an ultra-wide-band communication system and determines the overall performance of the system. The invention relates a microstrip ultra-wide-band band-pass filter based on a novel multi-branch multi-mode resonator. The filter is characterized in that two ends of an intermediate short-circuit transmission line node 33 are connected with two ends of a transmission line node 32 to form a closed loop, wherein the short circuit of the intermediate short-circuit transmission line node 33 is realized by a metalized through hole 34. An open-circuit transmission line node 31, an open-circuit transmission line node 35, an open-circuit transmission line node 36, an open-circuit transmission line node 37, an open-circuit transmission line node 38, and an open-circuit transmission line node 39 are respectively connected to the transmission line node 32. In addition, the filter performances are improved by connecting matching branches including a short-circuit transmission line node 12 and an open-circuit transmission line node 14 at an input port and connecting matching branches containing a short-circuit transmission line node 22 and an open-circuit transmission line node 24 at an output port, wherein the short circuit of the short-circuit transmission line node 12 is realized by a metalized through hole 13 and the short circuit of the short-circuit transmission line node 22 is realized by a metalized through hole 23. Researches show that the provided microstrip ultra-wide-band band-pass filter has advantages of high performance and miniaturization and the like.

The invention relates to a multiband terahertz filter. The terahertz filter comprises a substrate and a metal film which are arranged in sequence from bottom to top, wherein a periodic structure is etched on the metal film; the periodic structure consists of n concentric annuli; n is a wave band quantity of the terahertz filter; the widths of the n concentric annuli are gradually increased from circle centre to outside. The invention also discloses a manufacture method of the multiband terahertz filter. As passing bands are increased, the multiband terahertz filter provided by the invention has the advantages of having good out-of-band rejection performance of the middle passing bands, polarization insensitivity and wide acceptance angle, and realizing the controllability of filtering frequency band and wave band quantity of the filter; the manufacture method is simple to operate; the multi-step technologies of the manufacture method all refer to conventional operations in the semiconductor field; the large-scale and integrated production is easy.

The invention discloses a miniaturized frequency selection surface based on a double-opening resonance ring. A band-pass effect is formed through the combined action of the double-opening resonance ring and a middle coupling aperture. When electromagnetic wave is irradiated to the frequency selection surface, resonance is caused by the opening resonance ring. The frequency selection characteristicof the opening resonance ring is utilized, so that a high spatial filtering function is achieved, meanwhile, the miniaturization characteristic is realized; compared with a common frequency selectionsurface, the cell area is greatly reduced, and the size of the whole circuit unit is only 0.3lambda 0*0.3lambda 0; meanwhile, by virtue of mutual coupling between the opening gap of the resonance ring and an interlayer coupling window, a good out-of-band rejection effect is achieved; and a transmission zero point is arranged on each of the two sides of the band, so that the rectangular coefficient of the circuit is greatly improved. A symmetrical circuit structure is adopted, so that the structure is simple, and machining is easy; and meanwhile, the whole circuit is quite high in stability around the incident angle theta and a formula which is as shown in the specification, so that the practical value is increased.

The invention discloses a differential absorption laser radar ozone space-time distribution day and night automatic detection device based on double Raman tube light source. The device comprises a laser transmitting unit, an optical receiving unit, a signal collecting unit and a signal analyzing unit, wherein the laser transmitting unit adopts D2 and H2 double Raman tube light source systems; the laser transmitting unit is used for transmitting laser of 266nm, 289nm, 299nm and 316nm simultaneously; the laser is received by the optical receiving unit; optical signals, which are transmitted by the optical receiving unit, are converted to digital signals through the signal collection unit, stored in an industrial personal computer and analyzed by the signal analyzing unit in real time. Echo signals of four channels are detected simultaneously; the requirements for detection precisions of different heights of a lower layer, a middle layer and a high layer of ozone in a convection layer can be taken into account. The device is capable of observing the ozone three-dimensional distribution of the convection layer around the clock, high in time resolution ratio and space resolution ratio and high in detection precision.

The invention relates to a single-layer dual-circular polarization cavity backed traveling wave antenna with a filtering function. Most of back cavity filtering antennas are of a multi-cavity structure; although good filtering characteristics can be achieved, the defects of high profile, large size, high cost and the like of the back cavity filtering antennas limit the application of the filteringantennas. According to the invention, the integrated design of the antenna and the filter is carried out in the single-layer single substrate integrated waveguide cavity, and the functions of a band-pass filter and a circularly polarized radiator are realized at the same time. In addition, different ports of the filtering antenna are fed respectively, and the other port is connected with a load to realize left-handed circular polarization radiation and right-handed circular polarization radiation respectively. The filtering antenna has good filtering characteristics, wide bandwidth and high gain, and is simple in structure and easy to process and manufacture.