CN201490985U - Three-channel surface acoustic wave filter - Google Patents
Three-channel surface acoustic wave filter Download PDFInfo
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- CN201490985U CN201490985U CN2009201875895U CN200920187589U CN201490985U CN 201490985 U CN201490985 U CN 201490985U CN 2009201875895 U CN2009201875895 U CN 2009201875895U CN 200920187589 U CN200920187589 U CN 200920187589U CN 201490985 U CN201490985 U CN 201490985U
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- interdigital transducer
- acoustic wave
- surface acoustic
- channel
- wave filter
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Abstract
A three-channel surface acoustic wave filter comprises three filters with different frequency responses, wherein the three filters are integrated onto a piezoelectric crystal wafer. One filter is a single-channel surface acoustic wave filter formed by an independent input interdigital transducer, an independent output interdigital transducer and a shielding strip arranged between the independent input interdigital transducer and the independent output interdigital transducer. Another two filters are two-channel surface acoustic wave filters formed by two input-end interdigital transducers, a common output-end interdigital transducer and a shielding strip between the input-end interdigital transducer and the output-end interdigital transducer. An electrical isolation strip formed by metal strips and an acoustic isolation strip formed by sound-absorbing materials integrated between the single-channel filter and the two-channel filter on the piezoelectric crystal wafer work independently without mutual intervention. The three-channel surface acoustic wave filter integrates and realizes functions of three surface acoustic wave filters on a same chip inside a standard package, has smaller occupied chip area, saves one package outer casing, and has lower manufacturing cost.
Description
Technical field
The utility model relates to band pass filter, is specifically related to be integrated in the surface acoustic wave bandpass filter on the piezoelectric crystal material.
Background technology
Be carried in when voltage on the electrode of substrate material (for example lithium niobate monocrystal material), can in the lattice of piezoelectric crystal material, form the machinery distortion with piezoelectric property.When the signal of telecommunication of voltage that is carried on the piezoelectric crystal material electrode for importing, can form surface acoustic wave in the lattice on piezoelectric crystal material surface, this surface acoustic wave is a kind of elastic mechanical ripple that reduces rapidly with the increase of going deep into the substrate material degree of depth at the propagation of piezoelectric crystal material surface, amplitude.
Surface Acoustic Wave Filter has the characteristic of band pass filter.The realization of Surface Acoustic Wave Filter bandpass filtering function is the surface acoustic wave that forms based in the above-mentioned lattice.The basic structure of Surface Acoustic Wave Filter is to make certain thickness aluminium film on the burnishing surface with the substrate material of piezoelectric property (for example lithium niobate monocrystal material), on this aluminum membranous layer, be crossed as right pectination aluminium electrode structure by photoetching process formation, on this comb-shape electrode structure, apply the signal of telecommunication, just interdigital at two comb electrodes forms surface acoustic wave, therefore this comb-shape electrode structure plays a part electroacoustic transducer, is called interdigital transducer.The excitation area of interdigital formation transducer of two comb electrodes, the comb shank portion of each interdigital finger of connection of two comb electrodes is called busbar, and signal voltage puts on two busbars of interdigitated electrodes, and each busbar is connected with external circuit by electric contact.Interdigital transducer is divided into input transducer and output transducer again: the input transducer converts the electrical signal to the surface acoustic wave signal, propagates along plane of crystal, and output transducer becomes the surface acoustic wave conversion of signals that receives signal of telecommunication output again.Described input transducer and output transducer constitute the transmission channel of surface acoustic wave, and described transmission channel has different surface acoustic wave transmission characteristic or bandpass characteristics according to the different weights structure of interdigital transducer.
In the prior art, Surface Acoustic Wave Filter has single channel and two kinds of forms of binary channels.As the applicant's patent application, application number is that 2008101242125 patent application discloses a kind of single channel Surface Acoustic Wave Filter; Application number a kind of double-channel SAW filter that has been 2008101242178 patent disclosure.In television system of today, there are analog signal and digital signal simultaneously, need to use different filters, simultaneously, in the filtering of analog signal, again picture signal is used different filters with audio signal, so, often need to use simultaneously 2～3 Surface Acoustic Wave Filter, its shortcoming is that the crystal chip material that expends and covering base, pipe cap material are many, and it is big to take PCB (printed circuit board) area.
The content of utility model
The applicant provides a kind of three-channel acoustic surface wave filter, integrated and realize the function of the Surface Acoustic Wave Filter of three diverse frequency responses in a standard packaging shell and on same chip, make the chip area that takies littler, it is less to expend substrate material, manufacturing cost is lower, and it is littler to take the PCB area.
The technical solution of the utility model is as follows:
A kind of three-channel acoustic surface wave filter, comprise two input interdigital transducers that are integrated on the piezoelectric crystal plate, described two input interdigital transducer common output interdigital transducers, between described two input interdigital transducers and the described common output interdigital transducer shielding strip is set, constitutes double-channel SAW filter; Also be integrated with the single channel Surface Acoustic Wave Filter that constitutes by input interdigital transducer, output interdigital transducer and shielding strip between the two on the piezoelectric crystal plate; On piezoelectric crystal plate, be provided with between described double-channel SAW filter and the single channel Surface Acoustic Wave Filter and also be integrated with electric isolation band that constitutes by bonding jumper and the acoustics isolation strip that constitutes by sound-absorbing material.
Its further technical scheme is:
Described electric isolation band can be made of the metal material identical or different with forming interdigital transducer; The material of described acoustics isolation strip can be used to absorb the sound-absorbing material of reflected wave identical or different with coating the piezoelectric chip two ends.
Described electric isolation band can adopt identical or different metal material with interdigital transducer; The piezoelectric chip two ends can be adopted and coat in described acoustics isolation strip, and to be used to absorb the sound-absorbing material of reflected wave identical or different.Described acoustics isolation strip can overlappingly be arranged on the electric isolation band above, also can be arranged in the one or both sides of electric isolation band.
Useful technique effect of the present utility model is:
The integrated Surface Acoustic Wave Filter of three diverse frequency responses on the same chip of the utility model in a package casing.And on the piezoelectric chip between the filter of different frequency response, the electric isolation band is set to avoid the phase mutual interference of the signal of telecommunication, and the acoustics isolation strip is set simultaneously, avoid the phase mutual interference of sound wave between the different frequency response, thereby improve the selectivity of filter.Owing on same chip, realized the function of three filters, make that the chip area that takies is littler, it is less to expend substrate material, effectively reduces manufacturing cost.
Description of drawings
Fig. 1 is the schematic diagram of the utility model structure embodiment.
Fig. 2 is for cutting the schematic diagram that refers to weighting envelope structure on Fig. 1 input interdigital transducer.
Embodiment
Below in conjunction with accompanying drawing embodiment of the present utility model is described further.
See Fig. 1, the utility model comprises the double-channel SAW filter 29 that is made of the shielding strip 17 between input interdigital transducer 2, input interdigital transducer 5, output interdigital transducer 12 and two input interdigital transducers and the output interdigital transducer respectively that is integrated on the piezoelectric crystal plate 7, two input interdigital transducers 2, input interdigital transducers 5 are two staggered side by side interdigital transducers of cutting the finger weighting, and formed two transmission channels constitute two surface acoustic wave transversal filters.A shared output interdigital transducer 12 can make the output impedance of two filters identical, is convenient to carry out Circuit Matching.In addition, constitute single channel Surface Acoustic Wave Filter 30 by input interdigital transducer 20 and output interdigital transducer 26 and shielding strip between the two 23.Between described double-channel SAW filter 29 and the single channel Surface Acoustic Wave Filter 30 on piezoelectric crystal plate 7, also be integrated with electric isolation band 18 that constitutes by bonding jumper and the acoustics isolation strip 31 that constitutes by sound-absorbing material, be used to guarantee that double-channel SAW filter 29 and single channel Surface Acoustic Wave Filter 30 work alone separately, do not disturb mutually.
Described acoustics isolation strip 31 can adopt that to be used to absorb the sound-absorbing material band 32 and 33 of reflected wave identical with coating the piezoelectric chip two ends, also can be different, and for example can adopt the surface fluting to wait other acoustics isolation structures.Described electric isolation band 18 can adopt identical metal material (aluminium) and identical manufacture craft to make simultaneously with interdigital transducer, perhaps after interdigital transducer completes, adopt separately such as evaporation technologies such as (being not limited only to evaporation) and make with other metal materials.Described acoustics isolation strip 31 can overlappingly be arranged on electric isolation band 18 above, also can be arranged in the one or both sides of electric isolation band 18.Ground connection after electric isolation band 18 is connected with shielding strip 17 and shielding strip 23 among Fig. 1 embodiment.
Operation principle explanation of the present utility model:
The input interdigital transducer 2 of two channels filter, input interdigital transducer 5 are used for changing electric energy into surface acoustic wave mechanical energy; 12 of output interdigital transducers are opposite, change surface acoustic wave mechanical energy into electric energy, so finish the filtering and the transmission of signal; The input interdigital transducer 20 of described single channel filter is used for changing electric energy into surface acoustic wave mechanical energy; The output interdigital transducer is then 26 opposite, changes surface acoustic wave mechanical energy into electric energy, so finishes the filtering and the transmission of signal; Electric isolation band 18 and acoustics isolation strip 31 sound-absorbing material bands 18, assurance double-channel SAW filter and single channel Surface Acoustic Wave Filter are worked separately, do not disturb mutually.
See Fig. 1, wherein busbar 1, busbar 4, busbar 6, busbar 11, busbar 13 and busbar 19, busbar 22, busbar 24, busbar 25 are the power connection end mouth, are connected with the pin of package casing by the pressure welding silk respectively.The busbar 1 of input power connection end mouth, busbar 4, busbar 6, busbar 19, busbar 22 can be selected the different electric modes that connects, make the corresponding different frequency response of Surface Acoustic Wave Filter of three passages, for example can have performances such as different centre frequencies, bandwidth, the rectangle factor, the outer inhibition of band.When two busbars of the input interdigital transducer of described two channels filter had different current potentials, this interdigital transducer just can excite surface acoustic wave; And when two busbars of input interdigital transducer have same potential, then can not excite surface acoustic wave.For example among Fig. 1, when busbar 1 and busbar 4 insert different current potentials, and busbar 4 is when identical with busbar 6 current potentials, and input interdigital transducer 2 is worked, and input interdigital transducer 5 is not worked.When connect busbar 1, busbar 4 current potentials are identical, and the current potential of busbar 4, busbar 6 is not simultaneously, input interdigital transducer 2 is not worked, 5 work of input interdigital transducer.When the current potential of busbar 1, busbar 4 and busbar 4, busbar 6 not simultaneously, input interdigital transducer 2, input interdigital transducer 5 are worked simultaneously.The work of described single channel filter 30 and above-mentioned two channels filter 29 are not disturbed mutually, when busbar 19, busbar 22 current potentials not simultaneously, input interdigital transducer 20 operate as normal.
See Fig. 2, cut and refer to envelope 15, cut finger envelope 16 to be that input interdigital transducer 2 is through cutting the envelope that forms after the finger weighting, cutting finger envelope 8, cutting finger envelope 9 is that input interdigital transducer 5 processes are cut the envelope that forms after the finger weighting, cuts to refer to envelope 21, cut finger envelope 27 to be that input interdigital transducer 20 processes are cut the envelope that forms after the finger weighting.Side by side staggered cut cutting on the input interdigital transducers 5 that refer to weighting and refer to envelope 8, cut and refer to that cutting on envelope 9 and the input interdigital transducer 2 refers to envelope 15, cuts and refer to that main lobe zone 10 and main lobe regional 14 that envelope 16 constitutes respectively are staggered, is in the position that mutual intersection stacks for described two.Cutting in the described input interdigital transducer 20 refers to envelope 21, cuts finger envelope 27 formation main lobe zones 28.The input interdigital transducer obtains required frequency characteristic by the method for weighting that changes interdigital length.The cross section of the interdigital finger of input interdigital transducer 2, input interdigital transducer 5, input interdigital transducer 20 forms excitation main lobe zone 14, main lobe zone 10 and the main lobe zone 28 of interdigital transducer, and electric energy is converted to the surface acoustic wave energy in excitation area.Output interdigital transducer 12 and output interdigital transducer 26 is for waiting fourchette finger transducer, and it cuts the finger envelope is straight line, and the surface acoustic wave that receives in its excitation area can be converted to electric energy.
Above-described only is preferred implementation of the present utility model, and the utility model is not limited to above embodiment.Be appreciated that other improvement and variation that those skilled in the art directly derive or associate under the prerequisite that does not break away from spirit of the present utility model and design, all should think to be included within the protection range of the present utility model.
Claims (4)
1. three-channel acoustic surface wave filter, comprise the input interdigital transducer (2) and the input interdigital transducer (5) that are integrated on the piezoelectric crystal plate (7), described two input interdigital transducer common output interdigital transducers (12), between described two input interdigital transducers and the described common output interdigital transducer shielding strip (17) is set, constitutes double-channel SAW filter (29); Also be integrated with the single channel Surface Acoustic Wave Filter (30) that constitutes by input interdigital transducer (20), output interdigital transducer (26) and shielding strip between the two (23) on the piezoelectric crystal plate (7); It is characterized in that on piezoelectric crystal plate (7), also being integrated with between described double-channel SAW filter (29) and the single channel Surface Acoustic Wave Filter (30) electric isolation band (18) that constitutes by bonding jumper and the acoustics isolation strip (31) that constitutes by sound-absorbing material.
2. three-channel acoustic surface wave filter as claimed in claim 1 is characterized in that: described electric isolation band (18) can be made of the metal material identical or different with forming interdigital transducer; The material of described acoustics isolation strip (31) can be used to absorb the sound-absorbing material of reflected wave identical with coating the piezoelectric chip two ends, also can adopt different sound-absorbing materials.
3. three-channel acoustic surface wave filter as claimed in claim 1 or 2 is characterized in that: described acoustics isolation strip (31) and the overlapping setting of electric isolation band (18), acoustics isolation strip (31) be positioned at electric isolation band (18) above.
4. three-channel acoustic surface wave filter as claimed in claim 1 or 2 is characterized in that: described acoustics isolation strip (31) is positioned at the one or both sides of electric isolation band (18).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009201875895U CN201490985U (en) | 2009-09-15 | 2009-09-15 | Three-channel surface acoustic wave filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009201875895U CN201490985U (en) | 2009-09-15 | 2009-09-15 | Three-channel surface acoustic wave filter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201490985U true CN201490985U (en) | 2010-05-26 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009201875895U Expired - Lifetime CN201490985U (en) | 2009-09-15 | 2009-09-15 | Three-channel surface acoustic wave filter |
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| Country | Link |
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| CN (1) | CN201490985U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101656524B (en) * | 2009-09-15 | 2012-04-18 | 无锡市好达电子有限公司 | Three-channel surface acoustic wave filter |
| CN107733393A (en) * | 2017-11-22 | 2018-02-23 | 中国科学院微电子研究所 | Phononic crystal surface acoustic wave filter and manufacturing method thereof |
| CN112422099A (en) * | 2020-11-25 | 2021-02-26 | 成都燎原星光电子有限责任公司 | Chip structure of broadband low-loss surface acoustic wave filter |
-
2009
- 2009-09-15 CN CN2009201875895U patent/CN201490985U/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101656524B (en) * | 2009-09-15 | 2012-04-18 | 无锡市好达电子有限公司 | Three-channel surface acoustic wave filter |
| CN107733393A (en) * | 2017-11-22 | 2018-02-23 | 中国科学院微电子研究所 | Phononic crystal surface acoustic wave filter and manufacturing method thereof |
| CN107733393B (en) * | 2017-11-22 | 2021-04-23 | 中国科学院微电子研究所 | Phononic crystal surface acoustic wave filter and manufacturing method thereof |
| CN112422099A (en) * | 2020-11-25 | 2021-02-26 | 成都燎原星光电子有限责任公司 | Chip structure of broadband low-loss surface acoustic wave filter |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20100526 Effective date of abandoning: 20090915 |