JP2636482B2 - Surface acoustic wave filter - Google Patents
Surface acoustic wave filterInfo
- Publication number
- JP2636482B2 JP2636482B2 JP2243161A JP24316190A JP2636482B2 JP 2636482 B2 JP2636482 B2 JP 2636482B2 JP 2243161 A JP2243161 A JP 2243161A JP 24316190 A JP24316190 A JP 24316190A JP 2636482 B2 JP2636482 B2 JP 2636482B2
- Authority
- JP
- Japan
- Prior art keywords
- acoustic wave
- surface acoustic
- wave filter
- electrodes
- normal type
- 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.)
- Expired - Lifetime
Links
- 238000010897 surface acoustic wave method Methods 0.000 title claims description 12
- 239000000758 substrate Substances 0.000 claims description 5
- 230000003247 decreasing effect Effects 0.000 claims description 2
- 239000007787 solid Substances 0.000 claims description 2
- 230000006866 deterioration Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
Landscapes
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は弾性表面波フィルタに関し、特にチューナー
の帯域切替え用等に使用される多出力型の弾性表面波フ
ィルタに関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface acoustic wave filter, and more particularly to a multi-output type surface acoustic wave filter used for switching a band of a tuner.
従来のこの種の弾性表面波フィルタは、第３図に示す
ごとく圧電性基板１上に、１つの正規型交叉指状電極２
と、これに対向させた複数のアポダイズ電極20〜22とを
配設した構成である。As shown in FIG. 3, a conventional surface acoustic wave filter of this type is provided on a piezoelectric substrate 1 with one regular type interdigital electrode 2.
And a plurality of apodized electrodes 20 to 22 opposed thereto.
上述した従来の多出力型の弾性表面波フィルタのう
ち、第３図に示す構成では、正規型交叉指状電極２の対
数が複数のアポダイズ電極20〜22のいずれの対向箇所で
も同数であるため、フィルタ帯域幅が10MHz以上異なる
場合には、アポダイズ電極20〜22の振幅特性をすべて補
正することができず、フィルタ特性の歪みや帯域内特性
の劣化を避けられない。In the conventional multi-output type surface acoustic wave filter described above, in the configuration shown in FIG. 3, the number of pairs of the regular interdigital electrodes 2 is the same at any of the opposing portions of the plurality of apodized electrodes 20 to 22. If the filter bandwidth differs by 10 MHz or more, the amplitude characteristics of the apodized electrodes 20 to 22 cannot all be corrected, and the distortion of the filter characteristics and the deterioration of the in-band characteristics cannot be avoided.
本発明の弾性表面波フィルタは、圧電性基板上に１つ
の正規型交叉指状電極とこの正規型交叉指状電極の各々
異なる平行な伝搬路上に対応してそれぞれ交叉指状に重
み付けを付与した複数のアポダイズ電極とを配設した多
出力型の弾性表面波フィルタにおいて、前記正規型交叉
指状電極はその対数を対向する各前記アポダイズ電極の
フィルタ特性に応じて対向する部分を段階的に増減させ
ている。In the surface acoustic wave filter of the present invention, one normal type interdigital electrode is weighted on the piezoelectric substrate so as to correspond to each different parallel propagation path of the normal type interdigital electrode. In the multi-output type surface acoustic wave filter provided with a plurality of apodized electrodes, the normal type interdigital electrode increases or decreases the number of opposing portions in steps according to the filter characteristics of the opposing apodized electrodes. Let me.
また、前記正規型交叉指状電極の対数を減じた部分の
電極を短絡接続された埋め込みのベタ電極としても良
い。Further, the electrode of the portion where the number of pairs of the normal type interdigital electrodes is reduced may be an embedded solid electrode that is short-circuited.
次に本発明について図面を参照して説明する。 Next, the present invention will be described with reference to the drawings.
第１図は本発明の第１の発明の一実施例を示す平面図
である。圧電性基板１の面上には、対向するアポダイズ
電極20〜22のフィルタ特性に合わせて電極対数を段階的
に変えると共に、不要な交叉指状電極部分をショートす
る短絡電極13を設け、その部分の弾性表面波を励振を除
去するように構成した１つの正規型交叉指状電極10を設
けてある。このような構成により、アポダイズ電極20〜
22の振幅の補正に適した正規型交叉指状電極10の振幅特
性が得られ、フィルタ帯域幅が10MHz以上異なる場合で
も、歪みや帯域内特性の劣化を防止できる。FIG. 1 is a plan view showing an embodiment of the first invention of the present invention. On the surface of the piezoelectric substrate 1, the number of electrode pairs is changed stepwise according to the filter characteristics of the opposing apodized electrodes 20 to 22, and a short-circuit electrode 13 for short-circuiting unnecessary interdigital electrodes is provided. One normal type interdigital electrode 10 configured to remove excitation of the surface acoustic wave is provided. With such a configuration, the apodized electrodes 20 to
The amplitude characteristics of the normal-type interdigital electrode 10 suitable for the correction of the amplitude of 22 can be obtained, and even when the filter bandwidths differ by 10 MHz or more, distortion and deterioration of the in-band characteristics can be prevented.
以上説明したように本発明によれば、１つの正規型交
叉指状電極の対数を対抗する複数のアポダイズ電極のフ
ィルタ特性に応じて段階的に増減することにより、フィ
ルタ特性の歪みや帯域内特性の劣化を制御できるので、
入力信号の分配を均等化でき、対数の少ない側のフィル
タ特性の損失増大を防止できる。As described above, according to the present invention, by increasing or decreasing the logarithm of one regular interdigital electrode in accordance with the filter characteristics of a plurality of opposing apodized electrodes, distortion of the filter characteristics and in-band characteristics Can control the deterioration of
The distribution of the input signal can be equalized, and an increase in the loss of the filter characteristic on the side with a small logarithm can be prevented.
第１図および第２図は本発明の第１および第２の発明の
一実施例の平面図である。 １……圧電性基板、２〜4,10〜12……正規型交叉指状電
極、20〜24,30,31……アポダイズ電極、13……短絡電
極。1 and 2 are plan views of one embodiment of the first and second inventions of the present invention. 1. Piezoelectric substrate, 2-4, 10-12, regular interdigital electrodes, 20-24, 30, 31 apodized electrodes, 13 short-circuit electrodes.
Claims (2)
板上に１つの正規型交叉指状電極とこの正規型交叉指状
電極の各々異る平行な伝搬路上に対応してそれぞれ交叉
指状に重み付けを付与した複数のアポダイズ電極とを配
設した多出力型の弾性表面波フィルタにおいて、前記正
規型交叉指状電極はその対数を対向する各前記アポダイ
ズ電極のフィルタ特性に応じて対向する部分を段階的に
増減させたことを特徴とする弾性表面波フィルタ。1. A surface acoustic wave filter according to the present invention comprises: a normal type interdigital electrode on a piezoelectric substrate and cross fingers corresponding to different parallel propagation paths of the normal type interdigital electrode. In a multi-output type surface acoustic wave filter provided with a plurality of apodized electrodes weighted in a shape, the normal type interdigital electrodes face the logarithm thereof according to the filter characteristics of each of the apodized electrodes. A surface acoustic wave filter characterized by gradually increasing or decreasing a portion.
分の電極を短絡接続された埋め込みのベタ電極とするこ
とを特徴とする請求項１記載の弾性表面波フィルタ。2. The surface acoustic wave filter according to claim 1, wherein a part of said normal type interdigital electrode having a reduced number of pairs of electrodes is a short-circuited buried solid electrode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2243161A JP2636482B2 (en) | 1990-09-13 | 1990-09-13 | Surface acoustic wave filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2243161A JP2636482B2 (en) | 1990-09-13 | 1990-09-13 | Surface acoustic wave filter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04122115A JPH04122115A (en) | 1992-04-22 |
| JP2636482B2 true JP2636482B2 (en) | 1997-07-30 |
Family
ID=17099715
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2243161A Expired - Lifetime JP2636482B2 (en) | 1990-09-13 | 1990-09-13 | Surface acoustic wave filter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2636482B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110243930B (en) * | 2019-06-19 | 2021-01-22 | 西南交通大学 | A surface acoustic wave formaldehyde gas sensor |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3878562D1 (en) * | 1988-11-11 | 1993-03-25 | Siemens Ag | SURFACE WAVE FILTER WITH CHANGEABLE TRANSMISSION AREA. |
-
1990
- 1990-09-13 JP JP2243161A patent/JP2636482B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04122115A (en) | 1992-04-22 |
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