CN109787578A - A kind of SAW filter of interdigital structure overcompensation - Google Patents
A kind of SAW filter of interdigital structure overcompensation Download PDFInfo
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- CN109787578A CN109787578A CN201811450879.4A CN201811450879A CN109787578A CN 109787578 A CN109787578 A CN 109787578A CN 201811450879 A CN201811450879 A CN 201811450879A CN 109787578 A CN109787578 A CN 109787578A
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- interdigital
- saw filter
- interdigital transducer
- square
- overcompensation
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Abstract
The invention discloses a kind of SAW filters of interdigital structure overcompensation, belong to filter field.The SAW filter includes piezoelectric substrate and input interdigital transducer and output interdigital transducer on piezoelectric substrate；In the input interdigital transducer and the output interdigital transducer, the end of each interdigital electrode increases by two squares, enables the end of each interdigital electrode T-shaped；The side length of the square is greater than the optical source wavelength for the litho machine selected, and the gap between each interdigital electrode and adjacent square is greater than the optical source wavelength for the litho machine selected；Solve the problems, such as that the insertion loss of SAW filter, relative bandwidth are not easy to meet the device compared with high type energy under existing manufacture craft；Reach under the premise of not changing the design structure, technique and encapsulation of SAW filter, the effect for reducing Insertion Loss, improving relative bandwidth, improving rectangular degree.
Description
Technical field
The present embodiments relate to filter field, in particular to the surface acoustic wave of a kind of interdigital structure overcompensation filters
Device.
Background technique
Surface acoustic wave is a kind of elastic wave propagated along body surface.SAW device have it is at low cost, small in size and
The features such as function is more have been widely used in fields such as radar, communication, navigation, identifications.Not with mobile communication technology
Disconnected rapid development, SAW filter have more superior performance, ultralow insertion loss, smaller size of encapsulation, height resistance to
The features such as power is inexorable trend.
The base material of SAW filter routine has the piezoelectric film materials such as quartz, lithium tantalate, niobic acid barium, will be interdigital
Energy converter is printed on piezoelectric membrane surface by techniques such as photoetching, plated films, and interdigital transducer passes through signal on piezoelectric membrane surface
Mutual conversion to achieving the effect that filtering.SAW filter currently on the market, due to by material electromechanical coupling
The limitation of the factors such as number, design scheme, manufacturing process, the bandwidth of SAW filter is generally the 5% of centre frequency hereinafter, lead to
In-band insertion loss is in 1db or more, and the rectangular degree of relative bandwidth is also not especially good.The technique of conventional interdigital transducer
Processing procedure can satisfy most of device performance index, but be directed to some more demanding performance devices, be set by change
Meter scheme or material etc. meet index.
Summary of the invention
In order to solve problems in the prior art, the embodiment of the invention provides a kind of surface acoustic waves of interdigital structure overcompensation
Filter.The technical solution is as follows:
In a first aspect, providing a kind of SAW filter of interdigital structure overcompensation, SAW filter includes
Piezoelectric substrate and input interdigital transducer and output interdigital transducer on piezoelectric substrate；
In the input interdigital transducer and the output interdigital transducer, the end of each interdigital electrode increases by two
Square enables the end of each interdigital electrode T-shaped；
The side length of the square is greater than the optical source wavelength for the litho machine selected, between each interdigital electrode and adjacent square
Gap be greater than select litho machine optical source wavelength.
Optionally, the size of the square is related with the period of SAW filter and the smallest finger width.
Technical solution provided in an embodiment of the present invention has the benefit that
Increase the side for being used for overcompensation by the end of the interdigital electrode of the interdigital transducer in SAW filter
Block enables the end of each interdigital electrode T-shaped, increases interdigital ring energy device in the excitation of end, improves surface acoustic wave and swashing
Encourage, transmit and conversion process in efficiency, solve the insertion loss of SAW filter, opposite band under existing manufacture craft
Width is not easy the problem of meeting the device compared with high type energy；Reached do not change SAW filter design structure, technique and
Under the premise of encapsulation, reduce Insertion Loss, raising relative bandwidth, the effect for improving rectangular degree.
Detailed description of the invention
To describe the technical solutions in the embodiments of the present invention more clearly, make required in being described below to embodiment
Attached drawing is briefly described, it should be apparent that, drawings in the following description are only some embodiments of the invention, for
For those of ordinary skill in the art, without creative efforts, it can also be obtained according to these attached drawings other
Attached drawing.
Fig. 1 is a kind of partial schematic diagram of interdigital transducer shown according to an exemplary embodiment；
Fig. 2 is a kind of partial schematic diagram of interdigital transducer shown according to an exemplary embodiment.
Specific embodiment
To make the object, technical solutions and advantages of the present invention clearer, below in conjunction with attached drawing to embodiment party of the present invention
Formula is described in further detail.
The present invention provides a kind of SAW filter of interdigital structure overcompensation, which includes
Piezoelectric substrate and input interdigital transducer and output interdigital transducer on piezoelectric substrate.
In input interdigital transducer and output interdigital transducer, the end of each interdigital electrode 11 increases by two squares
12, as shown in Figure 1, the end of each interdigital electrode is T-shaped.
The side length of each square is greater than the optical source wavelength for the litho machine selected, before each interdigital electrode and adjacent square
Gap be greater than select litho machine optical source wavelength.
As shown in Fig. 2, the gap b between each interdigital electrode and adjacent square is greater than the light source wave for the litho machine selected
It is long；The side length a of each square is greater than the optical source wavelength for the litho machine selected.
In order to enable the end of interdigital electrode in the interdigital transducer formed on piezoelectric substrate T-shaped, need to cover in photoetching
Increase corresponding block pattern in the functional graphic of film version；Using photoetching by the pattern transfer on lithography mask version to piezoelectric substrate
On.
Square is also needed in the position of the end of the interdigital electrode of interdigital ring energy device according to practical photoetching process process capability
And change.The size of square is related with the period of SAW filter and the smallest finger width.
As long as do not influence the performance of interdigital electrode, for example cause short circuit etc., the size of square is the bigger the better, but square
Size will also be limited by the period of SAW filter and the smallest finger width.
In conclusion end of the embodiment of the present invention by the interdigital electrode of the interdigital transducer in SAW filter
End increases the square for being used for overcompensation, enables the end of each interdigital electrode T-shaped, increases interdigital ring energy device swashing in end
It encourages, improves efficiency of the surface acoustic wave in excitation, transmission and conversion process, solve surface acoustic wave under existing manufacture craft and filter
The insertion loss of wave device, relative bandwidth are not easy the problem of meeting the device compared with high type energy；Reach and has not changed surface acoustic wave filter
Under the premise of the design structure of wave device, technique and encapsulation, the effect that reduces Insertion Loss, improve relative bandwidth, improve rectangular degree.
In addition, the photoetching resolution of square is high in this kind of compensation way, the overcompensation effect of figure is good, and early period is to original
It is relatively easy in GDS data handling procedure, while Multilevel compensating amendment may be implemented.
In one example, realizing -3db relative bandwidth can be improved the effect that 2% or more, Insertion Loss reduces 8.5% or more
Fruit.Such as: a centre frequency is 2442MHz, and original insertion loss is 1.442db, bandwidth 95M, even collocation structure is added
After the end of interdigital electrode is T-shaped, insertion loss 1.592db, bandwidth 97M.
It should be understood that the serial number of the above embodiments of the invention is only for description, do not represent the advantages or disadvantages of the embodiments.
The foregoing is merely presently preferred embodiments of the present invention, is not intended to limit the invention, it is all in spirit of the invention and
Within principle, any modification, equivalent replacement, improvement and so on be should all be included in the protection scope of the present invention.
Claims (2)
1. a kind of SAW filter of interdigital structure overcompensation, which is characterized in that the SAW filter includes pressure
Electric substrate and input interdigital transducer and output interdigital transducer on piezoelectric substrate；
In the input interdigital transducer and the output interdigital transducer, the end of each interdigital electrode increases by two sides
Block enables the end of each interdigital electrode T-shaped；
The side length of the square be greater than select litho machine optical source wavelength, between each interdigital electrode and adjacent square between
Gap is greater than the optical source wavelength for the litho machine selected.
2. SAW filter according to claim 1, which is characterized in that the size and surface acoustic wave of the square are filtered
The period of wave device is related with the smallest finger width.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811450879.4A CN109787578B (en) | 2018-11-30 | 2018-11-30 | Surface acoustic wave filter with interdigital structure overcompensation |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811450879.4A CN109787578B (en) | 2018-11-30 | 2018-11-30 | Surface acoustic wave filter with interdigital structure overcompensation |
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| CN109787578A true CN109787578A (en) | 2019-05-21 |
| CN109787578B CN109787578B (en) | 2023-02-28 |
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| CN201811450879.4A Active CN109787578B (en) | 2018-11-30 | 2018-11-30 | Surface acoustic wave filter with interdigital structure overcompensation |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110429917A (en) * | 2019-08-09 | 2019-11-08 | 宜确半导体（苏州）有限公司 | SAW filter and its manufacturing method |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000183681A (en) * | 1998-12-14 | 2000-06-30 | Seiko Epson Corp | Surface acoustic wave device |
| JP2001077655A (en) * | 1999-09-02 | 2001-03-23 | Kyocera Corp | Surface acoustic wave device and manufacture thereof |
| CN1606830A (en) * | 2001-12-21 | 2005-04-13 | 特梅克斯公司 | Method for forming surface acoustic wave filter device and surface acoustic wave filter device formed thereby |
| US20080079512A1 (en) * | 2006-09-29 | 2008-04-03 | Tdk Corporation | Surface acoustic wave filter and surface acoustic wave resonator |
| CN110572136A (en) * | 2019-09-09 | 2019-12-13 | 杭州左蓝微电子技术有限公司 | interdigital transducer |
-
2018
- 2018-11-30 CN CN201811450879.4A patent/CN109787578B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000183681A (en) * | 1998-12-14 | 2000-06-30 | Seiko Epson Corp | Surface acoustic wave device |
| JP2001077655A (en) * | 1999-09-02 | 2001-03-23 | Kyocera Corp | Surface acoustic wave device and manufacture thereof |
| CN1606830A (en) * | 2001-12-21 | 2005-04-13 | 特梅克斯公司 | Method for forming surface acoustic wave filter device and surface acoustic wave filter device formed thereby |
| US20080079512A1 (en) * | 2006-09-29 | 2008-04-03 | Tdk Corporation | Surface acoustic wave filter and surface acoustic wave resonator |
| CN110572136A (en) * | 2019-09-09 | 2019-12-13 | 杭州左蓝微电子技术有限公司 | interdigital transducer |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110429917A (en) * | 2019-08-09 | 2019-11-08 | 宜确半导体（苏州）有限公司 | SAW filter and its manufacturing method |
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| CN109787578B (en) | 2023-02-28 |
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Address after: 214124 Jiangsu province Binhu District of Wuxi City Economic Development Zone, Road No. 115 Applicant after: Wuxi Haoda Electronic Co.,Ltd. Address before: 214124 Jiangsu province Binhu District of Wuxi City Economic Development Zone, Road No. 115 Applicant before: SHOULDER ELECTRONICS Ltd. |
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