CN202759418U - Trapezoidal filter arranged on piezoelectric substrate - Google Patents
Trapezoidal filter arranged on piezoelectric substrate Download PDFInfo
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- CN202759418U CN202759418U CN 201220347213 CN201220347213U CN202759418U CN 202759418 U CN202759418 U CN 202759418U CN 201220347213 CN201220347213 CN 201220347213 CN 201220347213 U CN201220347213 U CN 201220347213U CN 202759418 U CN202759418 U CN 202759418U
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- dot matrix
- ladder
- piezoelectric substrate
- type filter
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Abstract
The utility model relates to a trapezoidal filter arranged on a piezoelectric substrate. The trapezoidal filter arranged on the piezoelectric substrate includes at least one pair of single-ended resonators. The pair of the single-ended resonators includes a serial single-ended resonator and a multipled single-ended resonator. The single-ended resonators are provided with a layer of two-dimensional metal dot matrix. The two-dimensional metal dot matrix has a plurality of dot matrix structural parameters. By adjusting the dot matrix structural parameters, an attenuation band for frequency response of the two-dimensional metal dot matrix is made overlapped with a far attenuation band of the trapezoidal filter arranged on the piezoelectric substrate and a passband for frequency response of the two-dimensional metal dot matrix is made overlapped with a passband of the trapezoidal filter arranged on the piezoelectric substrate, so that the out-of-band rejection of the far attenuation band of the trapezoidal filter arranged on the piezoelectric substrate is improved. And by adjusting the dot matrix structural parameters , the attenuation band for frequency response of the two-dimensional metal dot matrix is made overlapped with the passband of the trapezoidal filter arranged on the piezoelectric substrate, so that the bandwidth of the passband of the trapezoidal filter arranged on the piezoelectric substrate is reduced.
Description
Technical field
The utility model relates to a kind of ladder-type filter that is arranged on the piezoelectric substrate.
Background technology
The advantages such as Surface Acoustic Wave Filter is high with stable performance, reliable, high conformity and operating frequency, and bandwidth is flexible have remedied the deficiency of other filter, become the object of attracting attention of filter industry.Wherein ladder-type filter is low because having insertion loss, very smooth passband, do not need external match circuit and can bear the advantage such as very high power and be used widely, but its Out-of-band rejection is poor, be mainly reflected on the stopband far away, limited it suppresses to require the field outside high-band more application.
The people such as 0.Ikata had proposed the surface acoustic wave ladder-type filter at the article " Development of low-loss band-pass filters using SAW resonators for portable telephones " of IEEE ULTRASONICS SYMPOSIUM:pp.111-115 in 1992, were comprised of as shown in Figure 1 one-port resonator Zs and one-port resonator Zp in parallel by the series connection of electricity end.One-port resonator by placing interdigital transducer on the piezoelectric substrate, and is clipped in interdigital transducer the right and left by a pair of reflecting grating as shown in Figure 2.
The people's such as Y.Taguchi in 1997 patent " Surface acoustic wave filter with different filter portions satisfying complex conjugate relationship of impedances (US5592135) ", with Central China University of Science and Technology journal the 4th phase of the 39th volume: pp.20-24 in 2011, in the article " design and the emulation of SAW RF filter ", all proposed ladder-type filter and the dual mode filter (DMS) that vertically is coupled can be carried out cascade and realized the outer RF surface acoustic wave fliter that suppresses of high-band.Wherein the structure that proposes of Central China University of Science and Technology's journal article as shown in Figure 3, series arm resonator Zs and parallel arm resonator Zp form ladder-type filter and the cascade of DMS filter.Utilize the stopband of ladder-type filter and DMS filter to suppress complementary characteristics, the inhibition of nearly stopband and stopband far away all is greatly improved, but this design device area becomes large, complex structure.
Up to the present, do not increasing in design area, the situation simple in structure, the Out-of-band rejection on the solution ladder-type filter stopband far away is poor or realize that the scheme of the arrowband ladder-type filter that stopband Out-of-band rejection far away is strong still remains to be proposed.
The utility model content
The purpose of this utility model provides a kind of ladder-type filter that can address the above problem.
For achieving the above object, the utility model provides a kind of ladder-type filter that is arranged on the piezoelectric substrate.This ladder-type filter that is arranged on the piezoelectric substrate comprises at least one pair of one-port resonator, described a pair of one-port resonator comprises a series connection one-port resonator and an one-port resonator in parallel, has one deck two-dimensional metallic dot matrix on the described one-port resonator.
Further, described two-dimensional metallic dot matrix has a plurality of lattice structure parameters, by regulating described a plurality of lattice structure parameter, so that the stopband stack far away of the stopband of described two-dimensional metallic dot matrix frequency response and described ladder-type filter, so that the passband of the passband of described two-dimensional metallic dot matrix frequency response and described ladder-type filter superposes, improve the stopband Out-of-band rejection far away of described ladder-type filter simultaneously.
Further, described two-dimensional metallic dot matrix has a plurality of lattice structure parameters, by regulating described a plurality of lattice structure parameter, so that the stack of the passband of the stopband of described two-dimensional metallic dot matrix frequency response and described ladder-type filter narrows down the ladder-type filter pass band width.
Further, described a plurality of lattice structure parameter comprises one or more in length and width, dot matrix thickness and the thickness of electrode of dot matrix cycle, described dot matrix mid point.
Further, the cross sectional shape of described two-dimensional metallic dot matrix is square, rectangle, circle or oval.
The utility model does not increase design area, simple in structure, and the Out-of-band rejection of the stopband far away of energy Effective Raise ladder-type filter, and it is little to keep passband to change, and can also realize that stopband far away suppresses by force and pass band width narrows down.
Description of drawings
Fig. 1 is the ladder-type filter structure chart;
Fig. 2 is traditional one-port resonator structure chart;
Fig. 3 is two-dimensional lattice structure one-port resonator structure chart of the present utility model;
Fig. 4 is traditional ladder-type filter frequency response chart;
Fig. 5 is the frequency response chart of cycle 4.85 microns two-dimentional tungsten dot matrix;
Fig. 6 is the frequency response comparison diagram of cycle 4.85 microns two-dimentional tungsten lattice structure ladder-type filters and traditional ladder-type filter;
Fig. 7 is the frequency response chart of cycle 5.0 microns two-dimentional tungsten dot matrix;
Fig. 8 is the frequency response comparison diagram of cycle 5.0 microns two-dimentional tungsten lattice structure ladder-type filters and traditional ladder-type filter;
Embodiment
The utility model provides is arranged on ladder-type filter on the piezoelectric substrate, comprise at least one pair of one-port resonator, every pair of one-port resonator comprises a series connection one-port resonator and an one-port resonator in parallel, have one deck two-dimensional metallic dot matrix on each one-port resonator, so this ladder-type filter is simple in structure.
A plurality of lattice structure parameters by reasonable adjusting two-dimensional metallic dot matrix (a plurality of lattice structure parameters comprise in length and width, dot matrix thickness and the thickness of electrode of dot matrix cycle, described dot matrix mid point one or more), so that the stopband stack far away of the stopband of described two-dimensional metallic dot matrix frequency response and described ladder-type filter, so that the passband of the passband of described two-dimensional metallic dot matrix frequency response and described ladder-type filter superposes, improve the stopband Out-of-band rejection far away of ladder-type filter simultaneously; So that the stack of the passband of the stopband of two-dimensional metallic dot matrix frequency response and described ladder-type filter narrows down the ladder-type filter pass band width.
Below by drawings and Examples, the technical solution of the utility model is described in further detail.
In the present embodiment, a kind of structure that is arranged on the ladder-type filter on the piezoelectric substrate is that a two-dimensional metallic lattice structure is single-ended single-ended to parallel resonator to series resonator and a two-dimensional metallic lattice structure.
As shown in Figure 3, it is two-dimensional lattice structure one-port resonator structure chart.
Two-dimensional lattice structure one-port resonator comprises piezoelectric substrate 1, one-port resonator 2, two-dimensional metallic dot matrix 3.One-port resonator 2 is arranged on the piezoelectric substrate 1, at one-port resonator one deck two-dimensional metallic dot matrix is set.The shape of metal dots can be circular, square, ellipse or rectangle in the two-dimensional metallic dot matrix 2, and metal lattice can be made by tungsten, gold or copper metal material etc.Need to prove, the shape of metal dots also can be other shape in the two-dimensional metallic dot matrix 2, and also can be made by other materials, is not limited to shape and the material mentioned among the utility model embodiment.
The below does description for embodiment to the utility model according to design parameter.
It is 500MHz that single-ended centre frequency to series resonator is set, 0.38 micron of thickness, 8 microns of IDT cycles, 8.16 microns of reflecting grating cycles, 160 microns in aperture, IDT logarithm 116.5,10 pairs of reflecting grating logarithms; It is 480MHz that single-ended centre frequency to parallel resonator is set, 0.38 micron of thickness, 8.32 microns of IDT cycles, 8.16 microns of reflecting grating cycles, 163.2 microns in aperture, IDT logarithm 90.5,10 pairs of reflecting grating logarithms.This moment by single-ended frequency response to series resonator and single-ended traditional ladder-type filter that parallel resonator is consisted of as shown in Figure 4.
The two-dimensional metallic dot matrix adopts tungsten, this two dimension tungsten lattice parameter is set as follows: 4.85 microns of dot matrix cycles, length and width respectively are 2.425 microns, two dimension tungsten dot matrix thickness and interdigital aluminium thickness of electrode all at 0.5% λ to 10% λ scope, the surface acoustic wave wavelength that the λ piezoelectric substrate excites, in this scope, the two-dimensional lattice frequency response distributes and substantially remains unchanged.At this moment, the frequency response of cycle 4.85 microns two-dimentional tungsten dot matrix as shown in Figure 5.
In order to rise to the Out-of-band rejection of traditional ladder-type filter on stopband far away, the traditional ladder-type filter that sets is arranged on the piezoelectric substrate made from 360YX-LiTaO3,4.85 microns two-dimentional tungsten dot matrix of above-mentioned cycle are plated in the single-ended to series resonator and single-ended on the parallel resonator of traditional ladder-type filter, consist of two-dimentional tungsten lattice structure ladder-type filter.So that the stopband stack far away of the stopband in the frequency response of two-dimentional tungsten dot matrix and ladder-type filter, the passband of simultaneously two-dimentional tungsten frequency response and the stack of the passband of ladder-type filter keep the ladder-type filter passband to change little.
Two-dimensional metallic lattice structure ladder-type filter frequency characteristic is formed by ladder-type filter frequency response and two-dimensional metallic dot matrix frequency response superimposion.The frequency response contrast of these cycle 4.85 microns two-dimentional tungsten lattice structure ladder-type filters and traditional ladder-type filter as shown in Figure 6.Band connection frequency 490～510MHz keeps changing little, and the Out-of-band rejection of 515～550MHz is strengthened on the stopband far away.
It is 500MHz that single-ended centre frequency to series resonator is set, 0.38 micron of thickness, 8 microns of IDT cycles, 8.16 microns of reflecting grating cycles, 160 microns in aperture, IDT logarithm 116.5,10 pairs of reflecting grating logarithms; It is 480MHz that single-ended centre frequency to parallel resonator is set, 0.38 micron of thickness, 8.32 microns of IDT cycles, 8.16 microns of reflecting grating cycles, 163.2 microns in aperture, IDT logarithm 90.5,10 pairs of reflecting grating logarithms.This moment by single-ended frequency response to series resonator and single-ended traditional ladder-type filter that parallel resonator is consisted of as shown in Figure 4.
The two-dimensional metallic dot matrix adopts tungsten, this two dimension tungsten lattice parameter is set as follows: 5.0 microns of dot matrix cycles, length and width respectively are 2.5 microns, two dimension tungsten dot matrix thickness and interdigital aluminium thickness of electrode all at 0.5% λ to 10% λ scope, the surface acoustic wave wavelength that the λ piezoelectric substrate excites, in this scope, the two-dimensional lattice frequency response distributes and substantially remains unchanged.At this moment, the frequency response of cycle 5.0 microns two-dimentional tungsten dot matrix as shown in Figure 7.
In order to realize the arrowband ladder-type filter, the traditional ladder-type filter that sets is arranged on the piezoelectric substrate made from 360YX-LiTaO3,5.0 microns two-dimentional tungsten dot matrix of above-mentioned cycle are plated in the single-ended to series resonator and single-ended on the parallel resonator of traditional ladder-type filter, consist of two-dimentional tungsten lattice structure ladder-type filter.Make stopband and the stack of ladder-type filter passband in the frequency response of two-dimentional tungsten lattice point, thereby passband is narrowed down.
Two-dimensional metallic lattice structure arrowband ladder-type filter frequency characteristic is formed by ladder-type filter frequency response and two-dimensional metallic dot matrix frequency response superimposion.The frequency response contrast of these cycle 5.0 microns two-dimentional tungsten lattice structure ladder-type filters and traditional ladder-type filter as shown in Figure 8.Narrow band connection frequency is near 490MHz～497MHz, and the Out-of-band rejection of 500～550MHz is strengthened on the stopband far away.
The utility model does not increase design area, simple in structure, and make passband and the stopband of two-dimensional metallic dot matrix by the reasonable adjustment to the two-dimensional metallic lattice parameter, passband and stopband far away with the surface acoustic wave ladder-type filter superposes respectively, improve the Out-of-band rejection of ladder-type filter on stopband far away, and keep pass band width substantially constant, can also realize that stopband far away suppresses strong and pass band width narrows down.
It should be noted last that, above embodiment is only unrestricted in order to the technical solution of the utility model to be described, although with reference to preferred embodiment the utility model is had been described in detail, those of ordinary skill in the art is to be understood that, can make amendment or be equal to replacement the technical solution of the utility model, and not break away from the spirit and scope of technical solutions of the utility model.
Claims (2)
1. ladder-type filter that is arranged on the piezoelectric substrate, it is characterized in that, described ladder-type filter comprises at least one pair of one-port resonator, described a pair of one-port resonator comprises a series connection one-port resonator and an one-port resonator in parallel, has one deck two-dimensional metallic dot matrix on the described one-port resonator.
2. the ladder-type filter that is arranged on the piezoelectric substrate according to claim 1 is characterized in that, the cross sectional shape of described two-dimensional metallic dot matrix is square, rectangle, circle or oval.
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201220347213 CN202759418U (en) | 2012-07-17 | 2012-07-17 | Trapezoidal filter arranged on piezoelectric substrate |
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| CN 201220347213 CN202759418U (en) | 2012-07-17 | 2012-07-17 | Trapezoidal filter arranged on piezoelectric substrate |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106656098A (en) * | 2016-12-23 | 2017-05-10 | 无锡市好达电子有限公司 | Ultra-large-bandwidth surface acoustic wave filter |
| CN106788315A (en) * | 2017-01-09 | 2017-05-31 | 中科微声（天津）传感技术有限公司 | The SAW resonator that a kind of reflecting grating array metal lattice is accurately weighted |
| CN106788321A (en) * | 2017-01-09 | 2017-05-31 | 中科微声（天津）传感技术有限公司 | The SAW resonator of overall dot matrix reflection weighting |
-
2012
- 2012-07-17 CN CN 201220347213 patent/CN202759418U/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106656098A (en) * | 2016-12-23 | 2017-05-10 | 无锡市好达电子有限公司 | Ultra-large-bandwidth surface acoustic wave filter |
| WO2018113138A1 (en) * | 2016-12-23 | 2018-06-28 | 无锡市好达电子有限公司 | Ultra-large-bandwidth surface acoustic wave filter |
| CN106656098B (en) * | 2016-12-23 | 2020-11-24 | 无锡市好达电子有限公司 | Ultra-large bandwidth surface acoustic wave filter |
| CN106788315A (en) * | 2017-01-09 | 2017-05-31 | 中科微声（天津）传感技术有限公司 | The SAW resonator that a kind of reflecting grating array metal lattice is accurately weighted |
| CN106788321A (en) * | 2017-01-09 | 2017-05-31 | 中科微声（天津）传感技术有限公司 | The SAW resonator of overall dot matrix reflection weighting |
| CN106788315B (en) * | 2017-01-09 | 2020-06-19 | 广东斐瑞智能技术有限公司 | Surface acoustic wave resonator with accurately weighted reflection grid array metal dot matrix |
| CN106788321B (en) * | 2017-01-09 | 2020-06-19 | 广东斐瑞智能技术有限公司 | Integral lattice reflection weighted surface acoustic wave resonator |
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Granted publication date: 20130227 |