238 results about "Transmission zeros" patented technology

Dynamic puncturing in a wireless local area network (WLAN) supporting 320 MHz bandwidths is disclosed. In one example, a method includes a first station (STA1) transmitting a null data packet announcement (NDPA) frame including an indicator of an orthogonal frequency division multiple access (OFDMA) subchannel puncturing over a wireless medium and subsequently transmitting a null data packet (NDP) having a U-SIG field specifying an OFDMA puncturing pattern. The NDPA may indicate that the subsequent NDP, which preferably occupies an 80 MHz channel, includes the OFDMA puncturing pattern in its U-SIG field. The method may further include transmitting a beamforming report poll (BFRP) soliciting measurement by the receiving station (STA2) on active resources, e.g., subchannels which have not been punctured. STA2 may transmit a beamforming report (BFR) in response to the BFRP, the BFR including measurements of active resources excluding subchannels inactive due to static OFDMA puncturing or dynamic OFDMA puncturing.

An IPD high-selectivity band-pass filter based on a weak coupling transformer technology comprises an LC parallel resonance circuit, an LC series resonance circuit, an LC parallel resonance circuit and a fourth capacitor C4, and inductors in the LC parallel resonance circuit and inductors in the LC parallel resonance circuit have a weak transformer coupling relation; the coupling coefficient required by the weak coupling transformer provided by the invention is very small and can be realized in a mode of adjacently placing metals on the same layer, so that the structural complexity of the filter is effectively reduced; the band-pass filter is based on an IPD technology, an extra decoupling equivalent inductor is introduced through a weak transformer coupling technology, the extra decoupling equivalent inductor and a parallel capacitor which is connected between the input end and the output end of the filter in a bridging mode form a new resonance path, and a transmission zero point is introduced into an upper stop band and a lower stop band of the filter respectively to improve the selectivity of the filter. According to the invention, the selectivity of the filter can be effectively improved on the premise of not additionally introducing an inductance element and not increasing the order of the filter.

A compact substrate integrated waveguide triangular cavity dual-band band-pass filter is sequentially provided with an upper metal layer, a dielectric layer substrate clamped between the two metal layers and a lower metal layer from top to bottom, and the upper metal layer is connected with the lower metal layer through a metalized via hole. The middle dielectric layer substrate and the middle dielectric layer substrate form a cavity filled with dielectric, and the shape of the cavity is an isosceles right triangle. The whole filter is composed of four isosceles right-angle triangular cavities, and the whole filter is of a square structure. According to the invention, the passband parallel connection technology and the harmonic coupling control technology are combined, and the mode cross coupling technology is used, so that double passbands are realized, a transmission zero point is generated on a transition band between the two passbands, and the isolation degree between signals passing through the two passbands is improved. In addition, the whole filter is very simple and compact in structure.

The invention discloses a surface acoustic wave band-pass filter, a design method thereof and electronic equipment, and the method comprises the steps: determining a first structure parameter of a resonator, and determining a second structure parameter which comprises the piezoelectric material and thickness of a piezoelectric film; extracting a first relation and a second relation related to the in-plane transmission directions of the resonators; building a target filter based on the first relation and the second relation; the target filter comprises a basic resonator group and a compensation resonator group, the frequency temperature coefficient of the basic resonator group at the center frequency of the filter is zero, and the frequency temperature coefficient of the compensation resonator group at the transmission zero point is zero; and if the frequency temperature coefficient of the detected target filter is not zero, returning to the step of determining the second structure parameter until the frequency temperature coefficient of the detected target filter is zero. Through interaction of the resonators, it is guaranteed that the passband range of the filter does not change along with temperature change, and the band-pass filter with the frequency temperature coefficient being zero is achieved.

Methods and apparatus for communicating zero-padded signals related to zero padding of a transmission symbol that is to be transmitted in a wireless communication network. Signaling indicative of such zero padding is communicated between communication devices, and a zero-padded transmission symbol to which the zero padding has been applied, as well as a cyclic prefix preceding the zero-padded transmission symbol, are transmitted by a transmitting device and received by a receiving device. In some embodiments, the zero padding includes both head zero padding at a head of the transmission symbol and tail zero padding at a tail of the transmission symbol. Zero padding may also be applied to a reference signal sequence upon which a reference signal for channel estimation is based.

The invention discloses a high-abrupt-drop high-out-of-band rejection bulk acoustic wave filter circuit structure, which comprises a high-abrupt-drop circuit and a high-out-of-band rejection circuit, and is characterized in that the output end of the high-abrupt-drop circuit is connected with the high-out-of-band rejection circuit in series; the high-steep-drop circuit is a passive device externally expanded on a Ladder bulk acoustic wave filter circuit, and transmission zero point stepped distribution of a near-transmission band is realized; and the high out-of-band rejection circuit is used for externally expanding an inductor on the Ladder bulk acoustic wave filter circuit so as to construct a new transmission zero point of a specific frequency band at the far end of a transmission band to realize high out-of-band rejection. The circuit not only can realize high out-of-band rejection, but also can avoid the occurrence of a large peak at a near transmission band.

The utility model discloses a broadband terahertz waveguide band-pass filter with high out-of-band rejection. The broadband terahertz waveguide band-pass filter comprises an input waveguide, an output waveguide and a plurality of first band elimination elements, the input waveguide serves as the input end of the broadband terahertz waveguide band-pass filter, the output waveguide serves as the output end of the broadband terahertz waveguide band-pass filter, the width of any one of the first band-stop elements is smaller than the width of the input waveguide and the width of the output waveguide, and the width of any one of the first band-stop elements is smaller than that of the output waveguide. The plurality of first band-stop elements are sequentially arranged between the input end and the output end to form a high-frequency stop band of the broadband terahertz waveguide band-pass filter; therefore, a brand-new band-stop element branch structure is adopted to form a high-frequency stop band of the filter, so that the filter has a transmission zero point outside the high-frequency band, and meanwhile, the filter has the advantages of high out-of-band rejection and high bandwidth; therefore, the terahertz radio frequency transmission device is very suitable for large-scale application and popularization in the terahertz radio frequency transmission field.

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

The invention discloses an intermediate frequency filter chip based on a gallium arsenide IPD process, which adopts the GaAs IPD process with three metal layers and comprises six resonators, twelve capacitors and three metalized grounding holes. The six resonators are composed of capacitors C1-C6 and inductors L1-L6 which are connected in series / in parallel, the inductors are all of self-built octagonal structures, and wiring is only conducted on the middle layer and the uppermost metal layer; a branch series capacitor Ca-Cc and a main parallel capacitor Cd-Cf respectively form six transmission zeros outside a low-frequency band and a high-frequency band. According to the invention, the characteristics of small size and wide band of the filter chip are realized, the loss is reduced, the in-band flatness is improved, and the filter chip has high frequency selectivity and high out-of-band rejection capability.

The invention discloses a hybrid cascade band-pass frequency selective surface with flexibly designed pass-stop bands, and belongs to the technical field of electromagnetic fields and microwaves. The frequency selective surface is composed of two layers of structures, wherein the upper layer is of a grid square ring structure, and the lower layer is of a double-square ring structure. Under the condition that an additional electromagnetic structure is not introduced, the equivalent interlayer spacing of the upper-layer structure and the lower-layer structure is increased through staggered design of the upper-layer unit and the lower-layer unit, and the large-angle stability of the frequency selective surface is improved. According to the frequency selective surface, stable transmission performance of electromagnetic waves can be achieved within the frequency band of 3.3-3.8 GHz under the condition of different polarization and angle incidence, meanwhile, the frequency band where the pass-stop band of the frequency selective surface is located can adjust the side length size of the related square ring structure to achieve flexible design, and the frequency selective surface has the advantages of being simple in structure, low in cost and easy to popularize. The frequency selective surface has a transmission zero point outside a passband, so that a good stop-band characteristic can be realized.

The invention belongs to the technical field of microwave filter design, and particularly relates to a microstrip filter of a CQ frequency-variable coupling structure and a design method of the microstrip filter. The method comprises the following steps: firstly, according to required filter indexes, such as order, center frequency, bandwidth, return loss and transmission zero position, solving a transverse matrix M of a filter by utilizing a filter comprehensive theory; then performing similarity transformation and scaling transformation on the transverse matrix to eliminate unnecessary coupling terms in the transverse matrix so as to obtain a filter topological structure and a frequency-dependent coupling matrix M'which are easier to implement; a quarter-wavelength short-circuit stepped impedance resonator is selected as a resonance unit of the micro-strip filter simulation model; finally, relevant coupling parameters of the micro-strip filter simulation model are made to approach the theoretical coupling coefficient by adjusting relevant physical structure parameters of the resonator, and then design is completed. By introducing a frequency-dependent coupling mechanism into the structure, the position of a transmission zero point is flexible and controllable, and the spectrum selectivity and the out-of-band rejection capability of the filter can be effectively improved.

The invention discloses a high-selectivity waveguide filter based on a nonlinear frequency-variable coupling structure, which comprises three rectangular waveguide resonant cavities, an input waveguide port and an output waveguide port, and the first coupling metal column, the first coupling diaphragm, the first coupling metal block and the first metal baffle plate between the first resonant cavity and the second resonant cavity jointly form a first group of nonlinear frequency change coupling structures. And a second coupling metal column, a second coupling diaphragm, a second coupling metal block and a second metal baffle plate between the second rectangular waveguide resonant cavity and the third rectangular waveguide resonant cavity jointly form a second group of nonlinear frequency change coupling structures. The two groups of nonlinear frequency-variable coupling structures are used for coupling the three rectangular waveguide resonant cavities, and a reflection zero point and two transmission zero points are introduced into each rectangular waveguide resonant cavity, so that the filter response is a five-order Chebyshev response with four transmission zero points. The filter has the advantages of being compact in structure, high in selectivity, good in out-of-band rejection performance, simple in structure, easy to expand and the like, and has a good application prospect.

The invention discloses an ultrathin single-layer dual-passband frequency selective surface structure, and belongs to the field of electromagnetic fields and microwaves. The frequency selective surface structure is formed by periodically arranging the same unit structures, and each unit structure comprises a single-layer dielectric substrate and a single-layer metal layer loaded on the upper surface of the dielectric substrate; the single-layer metal layer is formed by sequentially nesting three concentric annular patches, and the three concentric annular patches are respectively a metal mesh tightly attached to the boundary of the unit, four square metal rings bent outwards and arranged in the metal mesh, and four circular metal rings bent outwards and arranged in the square metal rings from outside to inside. The ultra-thin single-layer dual-passband frequency selective surface structure can form two passbands with high relative bandwidths when electromagnetic waves are incident, has excellent angle stability under TE and TM polarization, and can be used for improving the performance of the antenna by changing the size parameters of the square metal ring and the circular metal ring. The two transmission zero points can be regulated and controlled, so that the position of the passband is adjusted.

The invention provides a multichannel SIW filtering jumper and a communication device, and belongs to the technical field of filtering jumpers. The multichannel SIW filtering jumper comprises m * n SIW rectangular dual-mode resonant cavities which are arranged in m rows and n columns and work in a TE102 and TE201 orthogonal degenerate mode, m > 0, and n > 0; each row of SIW rectangular dual-mode resonant cavities corresponds to a horizontal channel, each column of SIW rectangular dual-mode resonant cavities corresponds to a vertical channel, two adjacent SIW rectangular dual-mode resonant cavities are coupled through a common wall, and a coupling window is located in a weakest electric field area of any one of the SIW rectangular dual-mode resonant cavities. According to the multichannel SIW filtering jumper, the number of channels and the working center frequency, the working bandwidth, the working order and the transmission zero point of each channel can be independently set.

The invention belongs to the technical field of integrated circuits, and discloses a high-selectivity constant-bandwidth reconfigurable filter chip based on a GaAs (gallium arsenide) process, which comprises a dielectric substrate, a multilayer metal structure, a plurality of folded opening-shaped metal microstrip lines, a plurality of grounding metal columns, a variable capacitance diode, an MIM (metal injection molding) capacitor and the like. Resonance is realized in a mode of combining electric coupling and magnetic coupling, a variable capacitance diode is utilized to tune the center frequency, and the bandwidth is kept constant in the tuning process. Transmission zeros are introduced at two sides of a passband through cross coupling, so that the frequency selectivity and the spectrum management capability are remarkably improved, and meanwhile, the optimization of the microstrip interconnection structure effectively reduces the system loss. According to the invention, the strict requirements of a modern radio frequency communication system on miniaturization, high performance and high selectivity can be met, and extremely high adjustability and adaptability are achieved.

The invention discloses a high-isolation and high-selectivity filtering power divider with an input end broadband non-reflection characteristic. Comprising an input port, two output ports, a double-L-shaped non-reflection absorption structure, two microstrip connecting lines, two parallel coupling lines, two L-shaped step resonators, two non-reflection absorption isolation resistors, a quarter-wavelength parallel coupling connecting line and two U-shaped transmission lines. The input port is a first port; the two output ports comprise a port II and a port III; the double-L-shaped non-reflection absorption structure comprises a first non-reflection absorption resistor, a second non-reflection absorption resistor, a first L-shaped non-reflection absorption connecting line and a second L-shaped non-reflection absorption connecting line. According to the invention, the broadband reflection-free absorption characteristic of the input end and the broadband high isolation between the output ports are realized at the same time, a plurality of transmission zeros are introduced through the L-shaped step resonators, and the frequency selectivity and out-of-band rejection are improved.

The present invention provides an absorption-type balanced filter power divider with arbitrary transmission zero point, which relates to the field of communication technology and is constructed on a printed circuit board, comprising: a microstrip unit, a dielectric substrate and a metal ground arranged in sequence from top to bottom; a first absorption network, a first low-pass filter unit, a second absorption network, a second low-pass filter unit, a third low-pass filter unit, a third absorption network and a fourth low-pass filter unit are integrated on the microstrip unit, and the first absorption network, the first low-pass filter unit, the second absorption network, the second low-pass filter unit, the third low-pass filter unit, the third absorption network and the fourth low-pass filter unit are sequentially connected end to end to form a closed loop. The technical solution of the present invention overcomes the problems in the prior art that the common mode noise reflected by the balanced port cannot be absorbed and the suppression effect on unnecessary frequency bands is poor.

The present disclosure relates to a dual-mode filter, comprising: an electrically conductive casing defining a first resonance cavity and a second resonance cavity located adjacently and separated from each other by a partition wall inside the casing; a first cross-shaped TM dual mode dielectric resonator provided in the first resonance cavity and comprising a crossing portion and two horizontal arms and two vertical arms integrally extending from its crossing portion; and a second cross-shaped TM dual mode dielectric resonator provided in the second resonance cavity and comprising a crossing portion and two horizontal arms and two vertical arms integrally extending from its crossing portion. The first resonator and the second resonator are positioned substantially parallel to each other and coupled by a main coupling structure extending through the partition wall. An orthogonality-disrupting coupling structure is provided on a crossing portion of each of the first and second resonators and extends diagonally or parallel to a diagonal section of the crossing portion such that a first operation mode and a second operation mode of the resonator where the orthogonality-disrupting coupling structure is provided are coupled thereby. At least one cross-coupling window is provided in the partition wall. At least one conductive strip each extends across one cross-coupling window, without any conductive contact with the resonators and walls of the resonance cavities. Orientations of the orthogonality-disrupting coupling structures, a position, a shape and a size of the cross-coupling window, and a shape and a size of the conductive strip are selected in such a manner that the orthogonality-disrupting coupling structures, the at least one cross-coupling window and the at least one conductive strip cooperate with the main coupling structure together so as to have transmission zeros positioned in a controllable manner with respect to a passband of the filter. The present disclosure also relates to a communication device comprising an above-said dual-mode filter.

This disclosure provides a filter and a multiplexer including the same. The filter according to this disclosure includes: at least one series resonator unit connected in series between an input node and an output node, comprising a series resonator or comprising a series resonator and an inductor and / or capacitor connected in parallel or in series therewith; and at least one parallel resonator unit connected in parallel between a connection node and a ground node, comprising a parallel resonator or comprising a parallel resonator and an inductor and / or capacitor connected in parallel or in series therewith, the connection node being a node at the input and / or output of at least one series resonator unit and / or at least one parallel resonator unit being a composite resonator comprising a resonator. The filter according to this disclosure and the multiplexer including the filter can form more out-of-band transmission zeros in the filter's frequency response curve, thereby enhancing out-of-band attenuation.

This invention relates to the field of dual-passband filter technology and discloses an ultra-narrowband high-temperature superconducting symmetrical dual-channel filter. The invention establishes a high-order coupled topology based on CT and CQ units, enabling free adjustment of the zero positions between the two sub-passbands and the introduction of a pair of transmission zeros out of the dual-passband filter, thus achieving good sideband suppression between sub-passbands and throughout the entire dual-passband filter.

The invention relates to a band-pass filter structure and a design method, the band-pass filter structure comprises two SIW resonators which are distributed in a bilateral symmetry manner, adjacent surfaces of the two SIW resonators form a common wall, a second metal layer at least comprises a strip line resonator and a stepped strip line with two short-circuited ends, the two SIW resonators and the strip line resonator adopt a coplanar waveguide feed structure, and the two SIW resonators and the stepped strip line resonator are connected in parallel. The two SIW resonators are electrically coupled with the stepped strip line of which the two ends are short-circuited, and an inductive coupling window is arranged on a common wall to form magnetic coupling; the stripline resonator comprises a U-shaped half-wavelength stripline resonator with two short-circuited ends, an L-shaped quarter-wavelength stripline resonator or a combination of the U-shaped half-wavelength stripline resonator with two short-circuited ends and a full-wavelength stripline resonator. The number of transmission zero points is large and the positions are controllable through hybrid electromagnetic coupling, the order design of the filter is realized through the shape and the number of the combined strip line resonators, and the filter has the advantages of high selectivity and compact structure.

The invention discloses a band-pass filter and electronic equipment with the same, and relates to the technical field of microstrip filters. The band-pass filter comprises a dielectric substrate, a signal input end, a resonator array and a signal output end, the signal input end, the resonator array and the signal output end are sequentially arranged in the front area of the dielectric substrate, the signal input end and the signal output end are symmetrical about the center of the filter, and a grounding metal layer is arranged in the back area of the dielectric substrate; the signal input end comprises a signal input line and two first branch lines which form an included angle, and the lengths of the first branch lines are not equal; the resonator array comprises n + 1 resonators which are obliquely distributed, and n represents the order of the filter, is an integer and is greater than or equal to 1; the signal output end comprises a signal output line and two second branch lines which form an included angle, and the lengths of the second branch lines are not equal. By adopting the band-pass filter, the frequency selection characteristic is good, a plurality of transmission zeros can be provided at a low-end stop band and a high-end stop band, and the out-of-band rejection capability is effectively improved.

The invention discloses a lumped element and acoustic resonator mixed filtering balun and radio frequency front end system, which comprises a first module, a second module, a third module, a fourth module, a fifth module, a sixth module and a seventh module, and is characterized in that the first module, the third module and the fourth module are acoustic-electric mixed modules and comprise lumped elements and acoustic resonators; the first module, the fifth module, the sixth module and the seventh module are used for forming a plurality of transmission zero points outside a passband of the filtering balun so as to enhance the selectivity and out-of-band rejection of the edge of the passband, and the second module, the fifth module, the sixth module and the seventh module are electric modules, are formed by lumped elements and are used for realizing the passband of the required filtering balun. Reflection loss caused by impedance mismatching when discrete devices are cascaded can be avoided, insertion loss of a system is remarkably reduced, the size and cost of the system are reduced, the broadband advantage of an electrical filter and the high selectivity advantage of an acoustic filter are integrated, and meanwhile the high-performance filtering balun which is miniaturized, large in bandwidth and high in selectivity is achieved.

The application discloses a resonator, filter and multiplexer. The resonator comprises at least one LC resonant unit and at least one embedded resonant unit; the at least one LC resonant unit comprises at least one resonant element, the at least one resonant element comprises a first part, a second part and an interface between the two, and the interface connects the first part and the second part; the embedded resonant unit is embeddedly connected with the LC resonant unit through the interface. The application not only enables the LC resonant unit and the embedded unit to simultaneously filter the input signal, thereby ensuring the filtering performance of the resonator, but also enables the elements in the embedded resonant unit and the elements in the LC resonant unit to form a new resonant unit, and the input signal is filtered through the new filter unit, thereby not only improving the filtering effect of the resonator, but also increasing the signal transmission zero point of the filter, and further improving the filtering performance of the filter.

The invention discloses a small-size ultra-wide stopband lumped GaAs filter chip for 6G satellite communication internet, and relates to the technical field of radio frequency integrated circuit design, the filter chip comprises a GaAs substrate and an ultra-wide stopband lumped GaAs filter circuit arranged on the substrate, the ultra-wide stopband lumped GaAs filter chip comprises an input port and an output port, the input port is connected with the output port, and the output port is connected with the output port. The filter comprises an input port, an output port and a capacitance-inductance resonant coupling network connected between the input port and the output port, the capacitance-inductance resonant coupling network comprises four lumped inductors and five lumped capacitors, and three resonators and three capacitance-inductance couplings are formed, so that an out-of-band transmission zero point of the filter is realized, and the filter has a wide application prospect. According to the wide-stop-band band-pass filter, the novel circuit coupling topological structure is adopted, the IPD technology is combined, the device performance can be improved, meanwhile, the size of the filter is reduced, and the filtering characteristics of broadband high selectivity and wide stop band are achieved.

An antenna, antenna module, and electronic device. An antenna includes a first dielectric layer, a second dielectric layer, and a third dielectric layer. The second dielectric layer and the third dielectric layer are disposed on a same side of the first dielectric layer. The second dielectric layer and the third dielectric layer are disposed at different layers. A first radiating element is disposed at the first dielectric layer. A feed line is disposed at the second dielectric layer which feeds the first radiating element. A split resonance unit is disposed at the third dielectric layer, and in signal connection with the feed line. The split resonance unit is disposed on an input port of the antenna. In response to the split resonance unit operating on a resonant frequency thereof, the split resonance unit generates a transmission zero near the resonant frequency of the split resonance unit.

The invention provides a dual-passband waveguide filter and a coupling topology thereof, the dual-passband waveguide filter comprises a metal structure, the interior of the metal structure comprises a torispherical cavity and two sections of feed waveguides, the torispherical cavity is divided into four quarter-spherical cavities by partition plate structures, and the quarter-spherical cavities are communicated with the feed waveguides. Every two adjacent quarter spherical cavities are in coupling connection through a coupling window, and the two feed waveguides are respectively in coupling connection with the two opposite quarter spherical cavities through coupling windows. The dual-passband waveguide filter coupling topology comprises a cellular structure with a resonant node and a non-resonant node, a metal structure is in a physical presentation form of the cellular structure, a quarter spherical cavity is the resonant node, a feed waveguide is the non-resonant node, and the metal structure is a metal structure. According to the coupling topology theory, dual-passband band-pass filtering response of any even order can be realized, and limited transmission zeros are introduced into the lower stop band and the upper stop band of the two passbands at the same time, so that the stop band performance of the dual-passband band-pass filtering response is improved.

The invention relates to the technical field of radio frequency devices, in particular to an amplitude limiter circuit structure integrated with a filtering function by a gallium arsenide process, and the circuit sequentially comprises a 50-ohm microstrip input matching section, a first-stage amplitude limiting filtering unit, a second-stage amplitude limiting filtering unit and an output matching section along a main transmission line, in the first stage, three forward PIN diodes and three reverse PIN diodes are stacked and connected to a main circuit in parallel, high power tolerance and symmetrical amplitude limiting capacity are achieved, and two low-frequency transmission zero points are formed by fusing a micro-strip grounding branch knot and an MIM capacitor resonator; in the second stage, two anti-parallel PIN diodes are matched with a grounding inductor to form a third transmission zero point, three groups of resonant structures are integrated, six transmission zero points are introduced, the filtering performance in a 12-18GHz frequency band is remarkably enhanced, a PIN diode parasitic capacitor and a microstrip inductive structure are skillfully utilized by the circuit to cooperatively realize filtering, extra passive elements are not needed, and the cost is low. The method is suitable for integrated protection of sensitive devices in a high-frequency radar and communication system.

The invention relates to the field of broadband filters, and discloses a cavity broadband filter and capacitor coupling method, which comprises the following steps that a cavity is arranged in a broadband filter, a plurality of resonant columns are arranged in the cavity, and the resonant columns are arranged at preset intervals to form a resonant mode of the filter; a capacitor sheet is installed in the cavity, the capacitor sheet spans at least one resonant column, and energy transmission between the resonant columns is influenced through electric field coupling; and the end parts of the two sides of the capacitor sheet penetrate through the cavity and are grounded to form a transmission zero point. According to the invention, the capacitor sheets are additionally arranged in the cavity broadband filter, so that a transmission zero point is formed, the out-of-band rejection degree is improved, and a 7-order filter can achieve the effect of a 9-order filter. Therefore, the same suppression degree is ensured, the size of the filter is obviously reduced, the miniaturization design is realized, and the limitation requirements of space and weight are met.

The invention provides a third harmonic suppression film microstrip filter based on a mixed structure. Comprising a substrate, a pair of coplanar waveguide feeder lines used for being connected with an external circuit and playing a role in impedance matching, and a plurality of interdigital resonators used for generating passband characteristics of the filter, the hairpin resonator is used for generating a transmission zero point at the low end of the filter to improve low-end stop-band suppression, the 1 / 4 wavelength open-circuit lines are used for suppressing third harmonics of the filter, and the pair of coplanar waveguide feeder lines, the interdigital resonators, the hairpin resonator and the 1 / 4 wavelength open-circuit lines are all laid on the substrate. The plurality of interdigital resonators are located between the pair of coplanar waveguide feeders, the hairpin resonator is located between the plurality of interdigital resonators, the pair of coplanar waveguide feeders is connected with the interdigital resonators at two sides of the plurality of interdigital resonators, and the plurality of 1 / 4 wavelength open-circuit lines are connected with the pair of coplanar waveguide feeders in parallel.