JPH0595251A - Weighting electrode for surface acoustic wave filter - Google Patents
Weighting electrode for surface acoustic wave filterInfo
- Publication number
- JPH0595251A JPH0595251A JP27844691A JP27844691A JPH0595251A JP H0595251 A JPH0595251 A JP H0595251A JP 27844691 A JP27844691 A JP 27844691A JP 27844691 A JP27844691 A JP 27844691A JP H0595251 A JPH0595251 A JP H0595251A
- Authority
- JP
- Japan
- Prior art keywords
- electrode
- acoustic wave
- surface acoustic
- wave filter
- electrodes
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、弾性表面波フィルタに
係り、特に、弾性表面波フィルタの重み付け電極に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface acoustic wave filter, and more particularly to a weighting electrode for a surface acoustic wave filter.
【０００２】[0002]
【従来の技術】従来の弾性表面波フィルタに用いる重み
付け電極は、図３に示すような交叉幅２１を場所により
重み付け関数に比例して変化させるアポダイズド電極、
或いは図５に示すように、交叉幅３１が一定で該交叉幅
を有する電極指の密度を重み付け関数に比例して変化さ
せる間引き電極などが主に用いられている。2. Description of the Related Art A weighting electrode used in a conventional surface acoustic wave filter is an apodized electrode that changes a crossing width 21 as shown in FIG.
Alternatively, as shown in FIG. 5, a thinning electrode or the like which has a constant cross width 31 and changes the density of electrode fingers having the cross width in proportion to a weighting function is mainly used.
【０００３】[0003]
【発明が解決しようとする課題】これら従来の重み付け
電極にはそれぞれ欠点があり、場合により使い分けてい
るのが実状であった。即ち、図３に示すアポダイズド電
極は、重み付け関数を忠実に交叉幅により表現できる
が、重み付け係数の小さい部分、即ち交叉幅の狭い部分
は波の回折効果により誤差が生じ、フィルタ特性が劣化
しやすく、また電極から励振されるエネルギー分布２５
が図４に示す如く重み付け関数の分布により一定でない
ため、重み付け損失の原因となる、という欠点があっ
た。These conventional weighting electrodes have their respective drawbacks, and it is the actual situation that they are used properly depending on the situation. That is, in the apodized electrode shown in FIG. 3, the weighting function can be faithfully expressed by the crossing width, but an error occurs in a portion with a small weighting coefficient, that is, a portion with a narrow crossing width due to the wave diffraction effect, and the filter characteristics are easily deteriorated. , And energy distribution 25 excited by the electrode
4 is not constant due to the distribution of the weighting function as shown in FIG. 4, which causes a weighting loss.
【０００４】また、図５に示す間引き電極は、励振され
るエネルギー分布３４は均一（図６参照）であるが、交
叉幅の有無による密度の高低で重み付け関数を表現する
ため、アポダイズド電極に比べ量子化誤差が大きく、所
望の特性が得にくいという問題点があった。In the thinned-out electrode shown in FIG. 5, the excited energy distribution 34 is uniform (see FIG. 6), but since a weighting function is expressed by the density level depending on the presence or absence of the crossover width, the thinned-out electrode is compared with the apodized electrode. There is a problem that the quantization error is large and it is difficult to obtain desired characteristics.
【０００５】[0005]
【発明の目的】本発明は、かかる従来例の有する不都合
を改善し、とくに、弾性表面波フィルタに特有の量子化
誤差を少なくすることが可能な弾性表面波フィルタ用重
み付け電極を提供することを、その目的とする。SUMMARY OF THE INVENTION It is an object of the present invention to provide a weighting electrode for a surface acoustic wave filter which can improve the disadvantages of the conventional example and can reduce the quantization error peculiar to the surface acoustic wave filter. , And its purpose.
【０００６】[0006]
【課題を解決するための手段】本発明では、圧電基板上
に形成され交叉指電極で構成された弾性表面波フィルタ
用重み付け電極において、互いに隣合う複数の電極を有
すると共に、この各複数の電極相互間に、互いに接続さ
れた一対の浮き電極を設ける、という構成を採ってい
る。これによって前述した目的を達成しようとするもの
である。According to the present invention, a weighting electrode for a surface acoustic wave filter, which is formed on a piezoelectric substrate and is composed of interdigitated electrodes, has a plurality of electrodes adjacent to each other and the plurality of electrodes. The configuration is such that a pair of floating electrodes connected to each other are provided between the electrodes. This aims to achieve the above-mentioned object.
【０００７】[0007]
【発明の実施例】以下、本発明の一実施例を図１ないし
図２に基づいて説明する。この図１ないし図２に示す実
施例は、圧電基板上に形成され交叉指電極で構成された
互いに隣合う複数の電極１１，１４を有すると共に、こ
の各複数の電極１１，１４の相互間に、互いに接続され
た一対の浮き電極１７，１８が設けられている。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The embodiment shown in FIGS. 1 and 2 has a plurality of electrodes 11 and 14 which are formed on a piezoelectric substrate and which are formed by interdigitated electrodes and are adjacent to each other, and between the plurality of electrodes 11 and 14 respectively. , A pair of floating electrodes 17 and 18 connected to each other.
【０００８】すなわち、電極指１１及び１３はバス電極
１５と、電極指１２及び１４はバス電極１６とそれぞれ
接続されており、又、浮き電極１７及び１８は互いに接
続されている。電極指１１と浮き電極１７との交叉幅Ｗ
1 と、電極指１２と浮き電極１７との交叉幅Ｗ2 との和
（Ｗ1 ＋Ｗ2 ）、及び電極指１３と浮き電極１８との交
叉幅Ｗ3 と、電極指１４と浮き電極１８との交叉幅Ｗ4
との和（Ｗ3 ＋Ｗ4 ）は同じであり、かつ、場所によら
ず一定となる様にしてある。That is, the electrode fingers 11 and 13 are connected to the bus electrode 15, the electrode fingers 12 and 14 are connected to the bus electrode 16, and the floating electrodes 17 and 18 are connected to each other. Cross width W between the electrode finger 11 and the floating electrode 17
1, the sum of the overlap width W 2 between the electrode fingers 12 and the floating electrode 17 (W 1 + W 2), and the overlap width W 3 between the electrode fingers 13 and the floating electrode 18, the electrode finger 14 and the floating electrode 18 Crossing width W 4
And (W 3 + W 4 ) are the same, and are constant regardless of the place.
【０００９】この様に構成とすることにより、交叉幅Ｗ
1 とＷ2及び交叉幅Ｗ3 とＷ4 から励振される弾性表面
波の強さは（Ｗ1 −Ｗ3 ）＝（Ｗ4 −Ｗ2 ）に比例す
る。With this structure, the cross width W
The strength of the surface acoustic wave excited from 1 and W 2 and the cross widths W 3 and W 4 is proportional to (W 1 −W 3 ) = (W 4 −W 2 ).
【００１０】[0010]
【発明の効果】以上説明したように本発明によると、交
叉幅が場所によらず一定（Ｗ1 ＋Ｗ2 ）＝（Ｗ3 ＋
Ｗ4 ）でありながら、弾性表面波の励振強度は（Ｗ1 −
Ｗ3 ）＝（Ｗ4 −Ｗ2 ）に比例するため、従来のアポダ
イズド電極の欠点である回折効果による劣化が少なくな
り、かつ、従来の間引き電極のような量子化誤差による
設計上の制限がないという従来にない優れた弾性表面波
フィルタ用重み付け電極を提供することができる。As described above, according to the present invention, the crossing width is constant regardless of the location (W 1 + W 2 ) = (W 3 +
W 4 ), the excitation intensity of the surface acoustic wave is (W 1 −
Since it is proportional to W 3 ) = (W 4 −W 2 ), deterioration due to the diffraction effect, which is a drawback of the conventional apodized electrode, is reduced, and the design limitation due to the quantization error as in the conventional thinned electrode is limited. It is possible to provide an excellent weighting electrode for a surface acoustic wave filter, which has never existed before.
【図１】本発明の一実施例を示す重み付け電極の平面図
である。FIG. 1 is a plan view of a weighting electrode showing an embodiment of the present invention.
【図２】図１のエネルギー分布を示す説明図である。FIG. 2 is an explanatory diagram showing the energy distribution of FIG.
【図３】従来例のアポダイズド電極を示す平面図であ
る。FIG. 3 is a plan view showing an apodized electrode of a conventional example.
【図４】図３のエネルギー分布を示す説明図である。FIG. 4 is an explanatory diagram showing the energy distribution of FIG.
【図５】他の従来例における間引き電極を示す平面図で
ある。FIG. 5 is a plan view showing thinned electrodes in another conventional example.
【図６】図５のエネルギー分布を示す説明図である。FIG. 6 is an explanatory diagram showing the energy distribution of FIG.
１１，１２，１３，１４ 電極指 １５，１６ バス電極 １７，１８ 浮き電極 １９ 弾性表面波エネルギー分布 11, 12, 13, 14 Electrode fingers 15, 16 Bus electrode 17, 18 Floating electrode 19 Surface acoustic wave energy distribution
Claims (1)
された弾性表面波フィルタ用重み付け電極において、互
いに隣合う複数の電極を有すると共に、この各複数の電
極相互間に、互いに接続された一対の浮き電極を設けた
ことを特徴とする弾性表面波フィルタ用重み付け電極。1. A weighting electrode for a surface acoustic wave filter, which is formed on a piezoelectric substrate and is composed of interdigital electrodes, has a plurality of electrodes adjacent to each other and is connected to each other between the plurality of electrodes. A weighting electrode for a surface acoustic wave filter, comprising a pair of floating electrodes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27844691A JP2900663B2 (en) | 1991-09-30 | 1991-09-30 | Weighted electrodes for surface acoustic wave filters |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27844691A JP2900663B2 (en) | 1991-09-30 | 1991-09-30 | Weighted electrodes for surface acoustic wave filters |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0595251A true JPH0595251A (en) | 1993-04-16 |
| JP2900663B2 JP2900663B2 (en) | 1999-06-02 |
Family
ID=17597455
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27844691A Expired - Fee Related JP2900663B2 (en) | 1991-09-30 | 1991-09-30 | Weighted electrodes for surface acoustic wave filters |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2900663B2 (en) |
-
1991
- 1991-09-30 JP JP27844691A patent/JP2900663B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2900663B2 (en) | 1999-06-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP2068444B1 (en) | Acoustic wave filter | |
| KR20070104653A (en) | Elastic wave element | |
| JPH06260881A (en) | Surface acoustic wave convolver | |
| JPS616917A (en) | Internal reflection type unidirectional surface acoustic wave converter using change in electrode width | |
| JP2844968B2 (en) | Weighted electrodes for surface acoustic wave filters | |
| JPH0595251A (en) | Weighting electrode for surface acoustic wave filter | |
| JPH0548374A (en) | Weighting electrode for surface acoustic wave filter | |
| JPS61245613A (en) | Electric surface elastic wave filter | |
| JPS63110809A (en) | Surface acoustic wave propagation element | |
| EP1128553A3 (en) | Edge reflection type surface acoustic wave filter | |
| JP2714189B2 (en) | Surface acoustic wave filter and communication device using the same | |
| JPS6134755Y2 (en) | ||
| JPH02127809A (en) | Surface acoustic wave transducer | |
| JPS62219709A (en) | Surface acoustic wave resonator | |
| JPH05218787A (en) | Weighting electrode for surface acoustic wave filter | |
| JPH08265091A (en) | Surface acoustic wave device | |
| JPH10229317A (en) | Weighting electrode for surface-acoustic wave filter | |
| JP2001326552A (en) | Surface acoustic wave transducer | |
| JPH05121991A (en) | Reflection bank type unidirectional saw device | |
| JPH05218793A (en) | Surface acoustic wave filter | |
| JPH09205339A (en) | Surface acoustic wave element | |
| JP2529018Y2 (en) | IDT electrodes | |
| JPH05183371A (en) | Surface acoustic wave circuit | |
| JPH0389707A (en) | Surface acoustic wave filter | |
| JPS6181014A (en) | Surface acoustic wave device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 19990216 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| S111 | Request for change of ownership or part of ownership |
Free format text: JAPANESE INTERMEDIATE CODE: R313113 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080319 Year of fee payment: 9 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090319 Year of fee payment: 10 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090319 Year of fee payment: 10 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090319 Year of fee payment: 10 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090319 Year of fee payment: 10 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090319 Year of fee payment: 10 |
|
| LAPS | Cancellation because of no payment of annual fees |