CN104466317B - GaAs bimodule band-pass filter and preparation method thereof - Google Patents

Abstract

A kind of GaAs bimodule band-pass filter proposed by the present invention and preparation method thereof, it is desirable to provide one kind disclosure satisfy that miniaturization millimetre-wave circuit requirement, insertion loss is little, the high wave filter of selectivity.The technical scheme is that：Load minor matters and λ/2 resonator composition bending circulus branch line loaded type dual-mode resonator；It is transferred to by the two of wave filter physical channels output micro-strip from the microwave signal of input micro-strip feed-in, realize the pass-band performance of frequency selection, one of passage is that signal passes through input coupling minor matters and the transmission of output coupling minor matters, and an extra out-of-band transmission zero point is provided, the position of zero point is adjusted by the length of input coupling minor matters and output coupling minor matters and coupling distance；Another path microwave signal is coupled to dual-mode resonator by incoming feeder, then is coupled to output micro-strip by dual-mode resonator, and dual-mode resonator forms two transmission pole passbands and two transmission zero stopbands, and one of even mould for dual-mode resonator provides.

Description

GaAs bimodule band-pass filter and preparation method thereof

Technical field

The present invention relates to a kind of wave filter being applied to microwave and millimeter wave circuit and in particular to a kind of based on thin-film technique and The miniaturization of gallium arsenide substrate, low-loss, high selectivity bimodule band-pass filter chip.

Background technology

Wave filter is crucial passive device in radio communications system, and microwave band-pass filter is wherein important one Class, has obtained extensive research and has applied, such as cavity body filter, Parallel Coupled Line Microstrip Bandpass Filters, hair clip mode filter Etc..Microwave radio commu has gone through the development in more than halfth century, frequency resource use and exploitation deepens continuously, also become Obtain more and more nervous, therefore occur in that a popular research direction in the communications field in recent years, i.e. super narrow bandpass letter.It can be The high information of transfer rate in extremely narrow bandwidth, thus reach the unprecedented availability of frequency spectrum.It is reported that it is successful at present Super narrowband modulation in-flight test result is transfer rate to be 270kB/s in 2.7kHz bandwidth.Simultaneously in laboratory level Also have been able to accomplish reliable transmission 270kB/s data in the filter noise bandwidth of 2kHz.The experimental system of the U.S. exists Transmission T1 (1.544Mbps) data in the 30kHz channel width of AMPS.Used in reality, ultra-narrow band modulator approach has a lot Kind, such as 3PSK modulation, ACPRK modulation, MCM modulation, WPSK modulation, VMSK modulation, VPSK modulation, VMSK/2 modulation etc..But These methods can be all based on a kind of realization of wave filter by Successful utilization, that is, be suitable for the rectangular window of super narrowband modulation, ultra-narrow Founder H.K.Walker with modulation is referred to as zero group delay filter.The super narrowband modulation of analysis of ultra-narrow bandwidth filter Essence is using mutation phase place, is produced without the modulated signal of spread spectrum, reaches a kind of narrow modulation effect of very bandwidth.Ultra-narrow Band (UNB) efficient modulation techniques can obtain the very high availability of frequency spectrum, can effectively alleviate the present situation in short supply of frequency resource, thus Extensively concerned in recent years.Microwave filter generally uses distributed constant to realize, and the species of microwave resonator is various, according to institute With the type of resonator come point, dielectric filter, waveguide filter, coaxial line filter, microstripline filter can be divided into, band The wave filter of the compositions such as shape line resonator.Each of which resonator has advantage and the deficiency of oneself.Dielectric filter adopts The medium block of high-k low loss tangent, as resonator, has low-loss, acceptable temperature stability and little chi Very little the features such as, however, being limited by high cost and present process technology, its range is made to be limited in below 50GHz.Ripple Waveguide filter is designed and produced using waveguide resonant cavity, has low-loss, power capacity is big and can apply to the spies such as 100GHz Point, but its maximum shortcoming is, size is substantially big than other applicable resonators.Coaxial filter adopts coaxial resonant cavity Design and produce, have including excellent characteristics such as electromagnetic shielding, low loss characteristic and small sizes, but used above in 10GHz, then Due to its small physical size, make precision difficult to reach.Mini strip line resonator and stripline resonator have little size, By photoetching technique is easy to process and the advantages of being easily integrated of other active circuit element, many circuit are more biased towards such humorous Shake device.Its another big advantage is can be by the backing material using differing dielectric constant thus permissible in very big frequency range It is applied.However, comparing its Insertion Loss with other resonators, substantially ratio is larger, makes it be difficult to be answered in narrow band filter With.Microstrip filter has the advantages that size is little, lightweight, low cost, easy processing are integrated in microwave planar circuit or even microwave Extensively applied in circuit.Up to now the multiple micro-strip double-module resonators occurring include circular patch resonator, square patch Piece resonator, annulus resonator, square ring resonator, broken line ring resonator.The species of microstrip filter and way of realization are multiple many Sample, the micro-strip resonantor wave filter of miniaturisation high-performance is most commonly seen in actual use.Microstrip Bandpass Filter mainly has The forms such as parallel coupling wire type, interdigital wire type, cross-couplings formula.Traditional Microstrip Bandpass Filter is generally by the parallel coupling in λ/4 Close resonator or λ/2 Capacitance Coupled resonator is constituted, the cyclophysises due to microwave circuit frequency response make band filter Passband response is also had on harmonic frequency, thus cause wave filter upper side band frequency not precipitous, the problems such as passband is asymmetric.Cause This, will realize more preferable selectivity, and meet increasingly cumulative miniaturization needs, the demand to new microization microstrip filter More and more urgent.

Microwave T/R assembly, as the core component of Connectors for Active Phased Array Radar, seals frequently with multi-chip module (MCM) and three-dimensional The technology volumes such as dress (LTCC) are also done less and less；And satellite-based communications belong to full-duplex communication and (launch and receive and carry out, launch simultaneously Frequency is different with receives frequency).In order to suppress transmission channel to reveal the transmitting frequency band signals of coming, prevent receiving channel low noise from putting Big device saturation, protects being normally carried out of just communication, the wave filter of receiving channel becomes requisite device.

In order to strengthen the performance of phased array antenna, reduce the impact of antenna side lobe, antenna distance is generally less than operating frequency Half wavelength (waveguide wavelength in vacuum), frequency is higher, and the distance of T/R intermodule is less, to millimeter wave frequency band T/R intermodule Distance then only have several millimeters；And the installation dimension leaving wave filter for only has 1～2mm even more little, and adopt thin film work The parallel coupling of skill design, the traditional filter size such as interdigital line style are still larger, multistage coupling lead to insertion loss too big and Reduce the sensitivity of receiver, thus conventional lithographic techniques all can not meet needs in volume and performance for the microstrip filter.

Band filter is the microwave device being made up of microwave resonator.The wave filter of traditional communication base station mostly is single mode Chamber resonator (TE10 mould) and coaxial resonator (TEM mould), compared with cavity resonator, coaxial resonator volume is less.But with Frequency spectrum resource growing tension and crowded, and the requirement to circuit miniaturization for the development of integrated circuit is also increasingly stricter, makes Obtain wave filter and must have less area and volume under the premise of guarantee is high performance.Promote bimodulus cavity filter and medium humorous The device that shakes becomes study hotspot, and is gradually used for replacing conventional filter.Subsequently bimodulus dielectric resonator is also studied, its achievement It is used for replacing single mode of resonance wave filter, to reduce filter size further.Compared with double mould cavity resonator, bimodulus medium The volume of resonator is less, and Q-value is higher.Because each dual-mode resonator is equivalent to two resonant tanks, size and conventional single-mode Structure compares reduction half, and exactly these advantages make dual mode filter be widely studied, and pertinent literature also compares many.Due to every Individual mode of resonance can be equivalent to a resonant tank, and it has small volume, low cost, the advantages of performance is good, in actual work Widely used in journey.So far, the research of bimodulus or multi-mode filter is the most active in wave filter Miniaturization Research field Part, the design of novel miniaturization wave filter mostly is bimodulus form.Because the coupling of cavity dual mode filter is most absolutely Number is all electric coupling, and complicated coupled relation forms much irresistible zero points, is difficult to control (being somewhat similarly to zero chamber).Will be Wherein add a magnetic coupling, be difficult to accomplish.The implementation of cavity dual mode filter also has many kinds, every kind of dual mode filter Implementation also have many kinds, every kind of zero point implementation method that can have oneself, harmonic wave is not easily solved, and debugging is difficult, The coupled structure of the dual-mode resonator of various structures unstable although the inner couplings of resonator can be adjusted, but be difficult to adjust Coupling between resonator.Dielectric resonator has countless mode of resonance high because of the Q-value of its main mould TE01d mould, by parasitic mode shadow Sound is little, is used as to constitute filter passband in single mode dielectric filter.Resonant frequency and Jie because of dielectric resonator different mode The structure of matter is relevant, appropriate design media size, then dielectric resonator have two or three patterns resonant frequency close, have Two resonant frequencies, close to the dielectric resonator of pattern, can serve as dual mode filter；There are three resonant frequencies close to pattern Dielectric resonator, can be used as three mode filters.But dielectric resonator pattern complex distribution, parasitic mode many and also apart from passband pattern (TE01d mould) is near, and the impact that parasitic mode responds to wave filter is bigger, is relatively used for narrow-band filtering.

The bimodulus characteristic of resonator also has application in SAW filter, and its implementation is typically by right between two reflecting gratings Claim ground to place three transducers to constitute, for reduce loss, between reflecting grating and transducer and between transducer and transducer No mutation interval, in order to obtain the bandwidth of a few percent, piezoelectric substrate is generally leaky wave material, such as 42 ° tantalic acid niobiums, 36 ° of tantalums Sour niobium, 41 ° of niobic acid niobiums and 64 ° of niobic acid niobiums etc..The frequency response of wave filter depends on the structure constituting wave filter.Generally dual mode filter Wave filter by an input transducer, two output transducers, two peripheral short-circuiting reflection grid are constituted, and structure pair Claim, single order and three rank symmetric mode can be supported, thus referred to as dual mode filter.For reduce loss, between reflecting grating and transducer And between transducer and transducer, no mutation is spaced, and between transducer and transducer, has short transition transducer, this transducing Device is referred to as layout pitch transducer.The transmission characteristic of dual mode filter depends on finger logarithm, cycle, aperture and the film of unit The structural parameters such as thickness, these parameters are referred to as variable.Although multimode SAW filter small volume, Out-of-band rejection is good, and sound table is filtered More than ripple device, applicable frequency ratio is relatively low, and how within 20MHz～3GHz, and very bandwidth is narrow, and differential loss is big, and the scope of application is restricted.

Microstrip filter is as the important branch of wave filter, compared with double mould cavity resonator and multimode dielectric resonator, micro- Band bimodulus or multimode resonator volume are less, are more suitable for the system integration, this is because microstrip filter is planar structure, in sky Between on hardly account for volume, be easily achieved magnetic coupling in design, debugging is easily.By photoetching technique, machining accuracy is permissible Ensured well.In recent years, from the point of view of the paper statistics published, microstrip filter article accounts for wave filter research always literary composition More than half of chapter, especially for the research of small-sized double or multimode microstrip filter, always domestic and international academia Study hotspot, its achievement is also gradually used widely in systems such as electronics, radar, communications, also improves systematicness further Energy.Bimodulus micro-strip resonantor is achieved in that by introducing perturbed structure in resonator inside such as lamellar, ring-types, can make resonator The division of two orthogonal modes, thus realizing a resonator resonance in two frequencies, form a narrow band filter；This is existing As if Wolff (Wolfe, I., " Microstrip bandpass filter using serendipitous in 1972 degenerate modes of a microstrip ring resonator,”IEE Electron Lett.,Vol.8, No.12,302-303,1972.), devise first bimodulus ptototype filter simultaneously.Hereafter the bimodulus filter of multiple different structures Ripple device is devised, including the circulus of the chips such as square, circular, triangle and multi-form；It is mainly and wolff Theoretical corresponding closing structure, and the structure such as chip and ring-type is usually used in the design of high efficiency antenna, such in theory filtering Device has larger radiation loss；And the dual-mode resonator structure (Tu, W.H., " the Compact double- that are loaded based on branch line mode cross-coupled microstrip bandpass filter with tunable transmission Zeros, " IET Micro.Antennas Propag., Vol.2, No.4,373-377,2007.) it is easy to carry out parity mode divide Analysis, transmission zero is easily controllable and receive significant attention (as Fig. 4)；However, being used in below 10GHz above-mentioned dual mode filter more Frequency, this is because dual mode filter needs the coupling between very strong feeder line resonator so that coupling gap very little (in Fig. 4 shown in 15,16), often below 50 μm, and lithography process can not meet so narrow coupling gap, and with frequency The raising of rate, resonator (in Fig. 4 shown in 11～13) diminishes, and coupling gap length (11 and 12 length in Fig. 4) shortens, and also will Further shorten coupling length, then need narrower coupling gap, this is impossible to complete for current photoetching technique precision 's；Therefore, it is badly in need of developing suitable millimeter wave frequency band, the chip-type filter of miniaturization spaceborne phased array T/R module application.

Content of the invention

The present invention seeks in place of in view of the shortcomings of the prior art, providing a kind of small size, insertion loss is little, select Property high, Out-of-band rejection is good, disclosure satisfy that GaAs bimodule band-pass filter and its preparation side of miniaturization millimetre-wave circuit requirement Method.

The present invention is achieved by the following technical solutions, a kind of GaAs bimodule band-pass filter, including：Microwave-medium Layer, metal level and grounding conductor layer it is characterised in that：GaAs microwave-medium layer is coated on metal level and grounding conductor layer is upper and lower Between surface；Dielectric layer 3 is located at below metal level 1, is formed and uniformly fills rectangular dielectric plate, and shape is identical with dielectric layer bottom surface Grounding conductor layer 2 be located at dielectric layer 3 lower surface, and cover chip lower surface；Metal level 1 is formed with the high impedance line that symmetrically cracks 13rd, the loading minor matters of the constituted stepped impedance resonance of low-impedance line 14, and with λ/4 input resonator 11, λ/4 output resonator 12 are bent by shape together, the dual-mode resonator 11～14 of the bending circulus branch line loaded type of composition；Micro-strip width Input coupling arm for W1 and output coupling arm 5,6 pass through with described dual-mode resonator respectively input and output coupling gap 15, 16 are of coupled connections；Input coupling minor matters 9 and output coupling minor matters 10, are connected by the magnetic coupling producing between the two, coupling is strong Degree couples gap 17 by minor matters and determines；Input coupling arm 5 and output coupling arm 6 are to be symmetrical structure along centrage A-A ', around Dual-mode resonator connects input micro-strip 7 and the output micro-strip 8 at two ends；Pass through wave filter from the microwave signal of input micro-strip 7 feed-in Two physical channels be transferred to output micro-strip 8 in, realize frequency selection pass-band performance, one of passage is that signal passes through Input coupling minor matters 9 and output coupling minor matters 10 are transmitted, and provide an extra out-of-band transmission zero point, and the position of zero point is by defeated Enter to couple minor matters 9 and the length of output coupling minor matters 10 and coupling distance 17 is adjusted；Another path microwave signal passes through input Feeder line 5 is coupled to dual-mode resonator, then is coupled to output micro-strip 8 by dual-mode resonator, and dual-mode resonator forms two transmission poles Point passband and two transmission zero stopbands, one of transmission zero provides for the even mould of dual-mode resonator.

The present invention has the advantages that compared to prior art：

The present invention adopts 0.25- μm of gallium arsenide film Technology, by substrate is thinning, polishing, etching, photoetching, wiring, The techniques such as Ohmic contact, sputtering, plating make K-band dual mode filter, and the high accuracy characteristic using thin-film technique produces pole Narrow coupling gap (in Fig. 1 shown in input coupling gap 15, output coupling gap 16), because coupling gap is less, stiffness of coupling Bigger, therefore meet the close coupling characteristic of dual mode filter.Because dual-mode resonator small volume, the area of resonator only has 1.3mm × 1.2mm, compared with conventional films wave filter, the dual mode filter being made using GaAs technology is because required Resonator few (about reducing one times), shared conductor area is little, so it has smaller conductor losses, secondly because humorous Device size of shaking is little, and microwave paths traversed is short, so having smaller dielectric loss；Gallium arsenide film technique bimodulus is filtered Ripple device has merged retrofit technique and the advantage of dual-mode resonator, embodies in the following areas：First, GaAs material High-k is up to 12.9, compared with the low dielectric substrate of same thickness (as conventional ceramic dielectric constant 9.6), phase Little with the physical size required for electric wave length；Secondly GaAs technology comparative maturity, conventional GaAs circular wafer thickness is 100 μ M, only 74 μm of the width W1 of 50 Ω impedance lines, are conducive to the miniaturization of wave filter；Again GaAs wave filter with commonly use at present Active device chip is identical with passive device chip material, is easily integrated, such as LNA, power amplifier, frequency mixer and doubler etc.；With When dual mode filter input and output required for stiffness of coupling ratio larger because resonator corresponds to both of which, be equivalent to Two resonators of load, required stiffness of coupling is double, that is, correspond to input coupling gap 15 and output coupling gap 16 meeting in Fig. 1 Smaller, often less than 500 μm, using ordinary photolithographic process, precision cannot be ensured, and the precision of GaAs technology is up to several Micron, convenient design.Therefore, the close coupling required for dual-mode resonator can be realized easily by thin-film technique, and need Few one times of number of resonators (as a resonator herein realizes two resonators effects), so volume is less, such as institute above State, it has less loss, simultaneously micro-strip narrower width, the space bending beneficial to resonator to reduce volume (such as further λ/2 wavelength minor matters loaded type the resonator of 11～13 compositions in Fig. 1 is bent into as the bending resonator of 11～14 compositions in Fig. 2 Structure) therefore, thin-film technique dual mode filter solves that conventional filter volume is big, loss is high and is difficult to integrated shortcoming；This Outward, the minor matters that input and output microstrip line passes through between input coupling minor matters 9 and output coupling minor matters 10 couple gap 17 and are of coupled connections, Bandpasstilter stopband can be widened, improves belt resistance inhibitor system in the band more transmission zeros of outer introducing.The present invention has：

1. small size, filter with low insertion loss, selectivity is high.The area of the whole chip of Novel Filter designing herein is only 1.5mm × 1.3mm, from open source literature, is that area is minimum.The present invention adopts 0.25 μm of GaAs technology to make dual mode filter, Micron-sized gap is realized by the high accuracy feature of thin-film technique, realizes the close coupling needed for dual mode filter；Utilize simultaneously The less conductor losses of dual-mode resonator and dielectric loss characteristic, realize mini filter chip K-band filter with low insertion loss, can meet For wave filter volume and Channel depletion in the requirement of miniaturization millimetre-wave circuit, especially millimeter wave phased array T/R assembly Rigors.

2. concordance is good, using including the thin-film techniques such as evaporation, sputtering, chemical vapor deposition, by laser instrument in difference Under operating power and etching speed, etching is it is ensured that the concordance of performance of filter；For multichannel assembly, especially to phased Battle array T/R assembly etc. has the assembly concordance of thousands of passages significant.

3. structure is simple, easily designs, by being scalable filter frequencies to the regulation of a resonator, two transmission Limit can individually be adjusted, and extra out-of-band transmission zero point can be adjusted by the length and coupling distance that adjust coupling minor matters, strengthens The motility of wave filter design, improves the rejection ability of stopband, ensure that the miniaturization of wave filter simultaneously.

The branch line loaded type dual mode filter based on thin-film technique for the present invention, the Micrometer-Nanometer Processing Technology of comprehensive thin-film technique And the miniaturization technology of dual mode filter, solve big based on single technology filter size, pass-band loss is high, frequency selectivity is poor Problem；This wave filter comprises micro-strip dielectric-slab 3, dual-mode resonator (λ/4 input resonator 11, λ/4 output resonator 12, height Impedance line 13 and low-impedance line 14 are constituted), input coupling arm 5, output coupling arm 6 and On-wafer measurement coplanar waveguide structure (ground connection Hole 4, ground pad 18, input micro-strip 7 and output micro-strip 8 are constituted).Incoming feeder (input micro-strip 7, input coupling arm 5 and input Coupling minor matters 9 form) pass through minor matters coupling with output feeder (output micro-strip 8, output coupling arm 6 and output coupling minor matters 10 form) Joint close gap 17 realizes coupling, can provide more transmission zeros in stopband, strengthens Out-of-band rejection；Branch line in dual mode filter Load by the way of step electric impedance resonator (in SIR, such as Fig. 2, high impedance 13 and low-impedance line 14 are constituted), for replacing Fig. 1 In uniform λ/2 resonator high impedance line 13, to reduce the length loading minor matters；Whole filter construction is using bending ring-type knot Structure (λ/4 input resonator 11, λ/4 output resonator 12 in Fig. 2), to reduce circuit size further；Using GaAs technology The input coupling gap 15 of making, output coupling gap 16 up to micron order, the close coupling needs of dual mode filter can be met； This kind of wave filter has that passband is narrow, small volume, low, selectivity good, batch electrical property consistency high feature is lost；Can meet Circuit needs volume and the performance of wave filter being had higher requirements as millimeter wave phased array T/R module etc..

Brief description

Fig. 1 is the top view of GaAs bimodule band-pass filter of the present invention.

Fig. 2 is the A-A ' of Fig. 2 to sectional view.

Fig. 3 the present embodiment measuring transmission loss curve.

Fig. 4 is conditional branch line loaded type dual mode filter top view.

In figure：1 metal level, 2 grounding conductor layers, 3 microwave-medium layers, 4 ground holes, 5 input coupling arms, 6 output coupling arms, 7 input micro-strip, 8 output micro-strip, 9 input coupling minor matters, 10 output coupling minor matters, 11 λ/4 input resonators, 12 λ/4 outputs are humorous Shake device, 13 high impedance lines, 14 low-impedance lines, 15 input coupling gaps, 16 output coupling gaps, 17 minor matters coupling gaps, and 18 connect Ground pad.

Specific embodiment

Refering to Fig. 1.Embodiment following with the bimodulus GaAs wave filter to the present invention for the accompanying drawing illustrates.Following In the embodiment of description, bimodulus GaAs wave filter mainly includes：Microwave-medium layer 3, is formed at the metal of dielectric layer 3 upper surface Layer 1, is formed at the grounding conductor layer 2 of dielectric layer 3 lower surface, and ground hole 4.Metal level 1 is located at dielectric layer 3 surface, its shape Shape is as shown in the figure.Microwave-medium layer 3 material is GaAs, below metal level 1, is formed and uniformly fills Rectangular Enclosure with Participating Media completely Plate, microwave-medium layer 3 is coated between metal level 1 and grounding conductor layer 2 upper and lower surface.Grounding conductor layer 2 is located under dielectric layer 3 Surface, its shape is identical with dielectric layer bottom surface, and chip lower surface is completely covered.By corrosion surface metal level 1, retain shape For annular input coupling arm 5 and output coupling arm 6 and λ/4 input resonator 11, λ/4 output resonator 12, high impedance line 13, low The dual-mode resonator that impedance line 14 is constituted, composition metal layer 1.Metal level 1 is formed with the high impedance line 13 that symmetrically cracks, low-impedance line 14 Branch line loaded type dual-mode resonator (11～14) forming with λ/2 resonator (11,12)；Width be W1 input coupling arm and Output coupling arm (5,6) passes through input with described dual-mode resonator respectively and output coupling gap (15,16) are of coupled connections；Input Coupling minor matters 9 and output coupling minor matters 10, are connected by the magnetic coupling producing between the two, stiffness of coupling couples gap by minor matters 17 decisions；Input coupling arm 5 and output coupling arm 6 are to be symmetrical structure along centrage A-A ', connect two around dual-mode resonator The input micro-strip 7 at end and output micro-strip 8.

Described branch line loaded type dual-mode resonator is bending circulus (11～14), by λ/2 resonator 11, bimodulus Resonator is by positioned at the open-circuit resonant device (high impedance line 13 and low-impedance line 14) of centre of figure and λ/2 resonator, (λ/4 input Resonator 11 and λ/4 output resonator 12) constitute.Rectangle ground pad 18 is on metal level 1, micro- positioned at the input for W1 for the width Carry 7 both sides, and symmetrical being distributed in inputs micro-strip 7 both sides, rectangle ground hole is located at ground pad 18 center, runs through microwave-medium Layer is connected with grounding conductor layer 2.

The stepped impedance resonance structure (SIR) that described loading minor matters are made up of one section of high impedance line 13 and low-impedance line 14 Constitute.

The characteristic impedance of described input and output coupling arm (5,6) is 50 ohm, and corresponding micro-strip width is W1.

The live width of described coupling arm be 10 μm -200 μm, coupling arm to described dual-mode resonator coupling gap (15, 16) width is 5 μm -80 μm.

The second described metal is metal ground layer 2, positioned at the underface of described dielectric layer 3.

Described input and output minor matters coupling gap 17 is 5 μm -80 μm.

Described input micro-strip 7, output micro-strip 8, input coupling arm 5, output coupling arm 6, input coupling minor matters 9 and output Coupling minor matters 10 are connected.

In Fig. 2, the circuit structure of metal level 1 is with the symmetrical structure of the section of A-A ' line, so can cuing open in A-A ' line Electric wall is assumed in face.Because performance of filter is reciprocal, one of which situation is selected to be operated the explanation of principle.Input Coupling arm 5, output coupling arm 6 by being looped around around dual-mode resonator (12～14), by forming input coupling gap 15, defeated Go out to couple the coupling required for gap 16 is formed, input coupling minor matters 9 and output coupling minor matters 10 are passed through to form minor matters coupling slot Gap 17 forms coupling.

Referring to figure, the work of thin-film technique GaAs filter chip is illustrated.Using 0.25- μm of GaAs Film process technology, using including evaporation, sputtering, the thin-film technique such as chemical vapor deposition, by substrate thinning, polish, etch, The techniques such as photoetching, wiring, Ohmic contact, sputtering, plating make K-band bimodulus film filter；By laser instrument in different works Etching, corrosion surface metal level 1 under the rate of doing work and etching speed, make along the symmetrical ring-type input coupling arm 5 of centrage and defeated Go out coupling arm 6, and radially connected input coupling minor matters 9 and output coupling minor matters 10 are passed through to form minor matters coupling gap 17 formation coupling Close, input coupling arm 5 and output coupling arm 6 both sides are respectively symmetrically connection to arc both sides radially-protruding input micro-strip 7 and defeated Go out micro-strip 8, and make below this ring-type coupling arm with its with λ/4 input resonator 11 in arc parallel coupling gap 15,16, λ/ 4 output resonators 12, high impedance line 13 and low-impedance line 14, constitute the dual-mode resonator of open circuit or short circuit branch structure；Rectangle Ground pad 18 is symmetrically located at the upper and lower of the input micro-strip 7 that width is W1 and output micro-strip 8 end, and rectangle is grounded hole position In ground pad 18 center, run through microwave-medium layer 3 and be connected with grounding conductor layer 2.

It is transferred to by the two of wave filter physical channels output micro-strip 8 from the microwave signal of input micro-strip 7 feed-in, and Realize the pass-band performance of frequency selection.One of passage is that signal passes through input coupling minor matters 9 and output coupling minor matters 10 pass Defeated, and provide an extra out-of-band transmission zero point, the position of zero point can be by input coupling minor matters 9 and output coupling minor matters 10 Length and coupling distance 17 are adjusted；Another path microwave signal is coupled to dual-mode resonator (11 in Fig. 2 by incoming feeder 5 ～14 compositions), then output micro-strip 8 is coupled to by dual-mode resonator.Due to the mode abruption characteristic of dual-mode resonator, a path afterwards Two electric pathways of dual-mode resonator schizotype can be regarded as, dual-mode resonator can form two transmission poles and form passband again, Dual-mode resonator forms two transmission zeros and forms stopband simultaneously, and one of transmission zero carries for the even mould of dual-mode resonator For.The position of transmission zero can easily adjust ladder impedance resonance structure in dual-mode resonator, and (SIR, by high impedance line 13 He Low-impedance line 14 is constituted) size adjust, using SIR structure, be effectively reduced the physical size of resonator.

Input coupling gap 15 and output coupling gap 16 are primarily used to adjust the input of wave filter and output has load Q Value.

Ground hole 4 is filling hole with metal, is in pairs at respectively inputting the both sides of micro-strip 7 and output micro-strip 8, is formed coplanar Waveguiding structure, mainly facilitates on testboard in piece probe test, the microwave transmission characteristic of test filter；It is located at input micro- Determined by the probe model being used with the distance between two pairs of through holes on output micro-strip 8 both sides d with 7.Micro-strip live width therebetween Degree w1 can suitably be reduced preferably to be mated with external circuit.

Dual-mode resonator is mainly, using bending circulus, the purpose realizing reducing lateral dimension.Its overall shape not office It is limited to annular bending, rectangular bent may also be employed；Low-impedance line 14 is not limited to round, alternatively square, triangle, annular Close-shaped Deng other, low-impedance line 14 also can be replaced by metallic ground through hole in addition, form short-circuit line style and load resonator.

The shape phase that input coupling arm 4 and output coupling arm 5 are constituted with dual-mode resonator (l1～l4) using circulus Parallel, to realize bigger stiffness of coupling.Can be changed according to the difference using resonator shape, coupling gap is not limited to mark Quasi-parallel line style, can adopt square wave type, and the slow wave shape such as zigzag is it is therefore an objective to strengthen the coefficient of coup.Additionally, input coupling arm 4 With output coupling arm 5 be also not only limited to input and output micro-strip 7 or output micro-strip 8 top, also may extend to output micro-strip 7 or Below output micro-strip 8, purpose is equally to strengthen the coefficient of coup and provide more out-of-band transmission zero points.

Input coupling minor matters 9 and output coupling minor matters 10 are not limited to branched structure of opening a way, also can be in input coupling minor matters 9 It is the short circuit branch structure that grounding formation is made in open circuit branched structure or port with output coupling minor matters 10 port；Former in electricity The hybrid coupled pattern of latter can be changed into from the CGCM of the magnetic coupling parallel coupled line of former on reason.

It is this that microwave-medium layer (in Fig. 3 shown in the 2) material of the use of the present invention is not limited solely to GaAs (GaAs) Material or the other materials of suitable thin-film technique, such as silicon, germanium silicon material.

If Fig. 3 is the electric performance test curve chart of designed dual mode filter chip, as illustrated, dual mode filter exists The insertion loss of 22GHz is only 1.8dB, in the return loss S11 ＜ -35dB of 22.3GHz, has -35dB's at 24.2GHz Out-of-band rejection, has higher selectivity, if reduce selective requirement simultaneously, the pass-band loss of wave filter can be lower.

Claims (10)

1. a kind of GaAs bimodule band-pass filter, including：Microwave-medium layer, metal level and grounding conductor layer it is characterised in that： GaAs microwave-medium layer is coated between metal level and grounding conductor layer upper and lower surface；Dielectric layer（3）Positioned at metal level（1）Under Face, forms and uniformly fills rectangular dielectric plate, shape and dielectric layer bottom surface identical grounding conductor layer（2）Positioned at dielectric layer（3） Lower surface, and cover chip lower surface；Metal level（1）It is formed with the high impedance line that symmetrically cracks（13）, low-impedance line（14）Constituted The loading minor matters of stepped impedance resonance, and bent by shape together with λ/4 input resonator 11, λ/4 output resonator 12, The dual-mode resonator of the bending circulus branch line loaded type of composition（11～14）；Micro-strip width be W1 input coupling arm and Output coupling arm (5,6) passes through input and output coupling gap with described dual-mode resonator respectively（15、16）It is of coupled connections；Input Coupling minor matters（9）With output coupling minor matters（10）, connected by the magnetic coupling producing between the two, stiffness of coupling is coupled by minor matters Gap（17）Determine；Input coupling arm（5）With output coupling arm（6）Be along centrage A-A ' be symmetrical structure, humorous around bimodulus The device that shakes connects the input micro-strip at two ends（7）With output micro-strip（8）；From input micro-strip（7）The microwave signal of feed-in passes through wave filter Two physical channels be transferred to output micro-strip（8）In, realize the pass-band performance of frequency selection, one of passage is that signal leads to Cross input coupling minor matters（9）With output coupling minor matters（10）Transmission, and an extra out-of-band transmission zero point, the position of zero point are provided Put by input coupling minor matters（9）With output coupling minor matters（10）Length and coupling distance adjust；Another path microwave signal Dual-mode resonator is coupled to by incoming feeder, then output micro-strip is coupled to by dual-mode resonator（8）, dual-mode resonator formation two Individual transmission pole passband and two transmission zero stopbands, one of transmission zero provides for the even mould of dual-mode resonator.

2. as claimed in claim 1 a kind of GaAs bimodule band-pass filter it is characterised in that：Described input and output coupling Arm（5、6）Characteristic impedance be 50 ohm, corresponding micro-strip width be W1.

3. as claimed in claim 1 a kind of GaAs bimodule band-pass filter it is characterised in that：The live width of described coupling arm For 10 m-200 m, the coupling gap of coupling arm to described dual-mode resonator（15、16）Width be 5 m-80 m.

4. as claimed in claim 1 a kind of GaAs bimodule band-pass filter it is characterised in that：Grounding conductor layer（2）It is located at Described dielectric layer（3）Underface.

5. as claimed in claim 1 a kind of GaAs bimodule band-pass filter it is characterised in that：Described input and output minor matters Coupling gap（17）For 5 m-80 m.

6. as claimed in claim 1 a kind of GaAs bimodule band-pass filter it is characterised in that：Input coupling minor matters（9）With Output coupling minor matters（10）Couple gap by forming minor matters（17）Form coupling.

7. as claimed in claim 1 a kind of GaAs bimodule band-pass filter it is characterised in that：According to adopting resonator shape Difference and change, coupling gap be not limited to standard parallel line style, square wave type or zigzag slow wave shape.

8. as claimed in claim 1 a kind of GaAs bimodule band-pass filter it is characterised in that：Input coupling arm（4）With defeated Enter coupling arm（5）It is located at input input micro-strip（7）Or output micro-strip（8）Top, or extend to input micro-strip（7）Or output is micro- Band（8）Lower section, to strengthen the coefficient of coup and to provide more out-of-band transmission zero points.

9. as claimed in claim 1 a kind of GaAs bimodule band-pass filter it is characterised in that：Input coupling minor matters（9）With Output coupling minor matters（10）Port is the short circuit branch structure that grounding formation is made in open circuit branched structure or port；Former in electricity The hybrid coupled pattern of latter is changed into from the CGCM of the magnetic coupling parallel coupled line of former on reason.

10. a kind of process preparing GaAs bimodule band-pass filter described in claim 1 is it is characterised in that include as follows Step：Using 0.25- m gallium arsenide film Technology, by substrate is thinning, polishing, etching, photoetching, wiring, Ohmic contact, Sputtering, electroplating technology make K-band bimodulus film filter；Carved under different operating power and etching speed by laser instrument Erosion, corrosion surface metal level（1）, make along the symmetrical ring-type input coupling arm of centrage（5）With output coupling arm（6）, and footpath To connection input coupling minor matters（9）With output coupling minor matters（10）Couple gap by forming minor matters（17）Form coupling, input Coupling arm（5）With output coupling arm（6）Both sides are respectively symmetrically connection to the radially-protruding input in arc both sides micro-strip（7）And output Micro-strip（8）, and make below this ring-type coupling arm with it with arc parallel coupling gap（15、16）λ/4 input resonator （11）, λ/4 output resonator（12）, high impedance line（13）And low-impedance line（14）, constitute the double of open circuit or short circuit branch structure Mould resonator；Rectangle ground pad（18）It is symmetrically located at the input micro-strip that width is W1（7）With output micro-strip（8）End Upper and lower, rectangle ground hole is located at ground pad（18）Center, runs through microwave-medium layer（3）With grounding conductor layer（2）It is connected.