JPH02244811A - Surface acoustic wave filter using unidirectional converter - Google Patents
Surface acoustic wave filter using unidirectional converterInfo
- Publication number
- JPH02244811A JPH02244811A JP6504889A JP6504889A JPH02244811A JP H02244811 A JPH02244811 A JP H02244811A JP 6504889 A JP6504889 A JP 6504889A JP 6504889 A JP6504889 A JP 6504889A JP H02244811 A JPH02244811 A JP H02244811A
- Authority
- JP
- Japan
- Prior art keywords
- unidirectional
- surface acoustic
- electrode
- transducer
- acoustic wave
- 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.)
- Pending
Links
- 238000010897 surface acoustic wave method Methods 0.000 title claims abstract description 27
- 230000002457 bidirectional effect Effects 0.000 claims abstract description 19
- 239000002184 metal Substances 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 6
- 238000000151 deposition Methods 0.000 claims description 4
- 239000003989 dielectric material Substances 0.000 claims description 4
- 239000000758 substrate Substances 0.000 claims description 4
- 238000007796 conventional method Methods 0.000 claims description 3
- 238000007743 anodising Methods 0.000 claims description 2
- 238000005530 etching Methods 0.000 claims description 2
- 238000003780 insertion Methods 0.000 abstract description 10
- 230000037431 insertion Effects 0.000 abstract description 10
- 240000004050 Pentaglottis sempervirens Species 0.000 description 1
- 235000004522 Pentaglottis sempervirens Nutrition 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】
本発明は、中心に両方向性のインターディジタル電極を
配置し、その両側に一方向性変換器を配置（７た構造の
弾性表面波フィルタに関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface acoustic wave filter having a structure in which a bidirectional interdigital electrode is arranged at the center and unidirectional transducers are arranged on both sides.
一般に用いられている通常の弾性表面波インターディジ
タル電極（すだれ状電極）は、両方向性のため通過帯域
内で良好な特性を得るために、大きな挿入損失、例えば
１５ｄＢ以上の挿入損失の状態で用いられている。また
、中心に通常のインターディジタル電極を配置し、両側
に通常のインターディジタル電極を配置した３−トラン
スジューサ方式の弾性表面波フィルタが提案されている
。しかし、この方式では、両側のインターディジタル電
極が両方向性のため、最少でも３ｄＢの挿入損失が避け
られない。本発明は、両側に一方向性変換器を用いるこ
とにより、理想的にはＯｄＢの挿入損失のフィルタを得
ようとするものである。Generally used surface acoustic wave interdigital electrodes (interdigital interdigital electrodes) are bidirectional, so in order to obtain good characteristics within the passband, they are used with a large insertion loss, for example, 15 dB or more. It is being Furthermore, a three-transducer type surface acoustic wave filter has been proposed in which a normal interdigital electrode is arranged in the center and normal interdigital electrodes are arranged on both sides. However, in this method, since the interdigital electrodes on both sides are bidirectional, insertion loss of at least 3 dB is unavoidable. The present invention attempts to obtain a filter with an ideal insertion loss of OdB by using unidirectional converters on both sides.
第１図のように、圧電体基板１の上に、インターディジ
タル電極を配置して弾性表面波を励振、受信する構造の
弾性表面波フィルタにおいて、中心に両方向性のインタ
ーディジタル電極を配置し、その両側に、中心方向に方
向性５をもつグループ型の一方向性変換器３．４、或い
は３−位相型の一方向性変換器、を配置し、両側の一方
向性変換器の信号が同位相で加わるように電極６．７を
用いて両変換器を接続した構造の一方向性変換器を用い
ることにより、低挿入損失の弾性表面波フィルタが得ら
れる。As shown in FIG. 1, in a surface acoustic wave filter having a structure in which interdigital electrodes are arranged on a piezoelectric substrate 1 to excite and receive surface acoustic waves, a bidirectional interdigital electrode is arranged in the center, On both sides, group type unidirectional transducers 3.4 with directionality 5 in the center direction or 3-phase type unidirectional transducers are arranged, and the signals of the unidirectional transducers on both sides are A surface acoustic wave filter with low insertion loss can be obtained by using a unidirectional transducer having a structure in which both transducers are connected using electrodes 6.7 so that they are applied in the same phase.
特許請求の範囲第１項において、両方向性のインターデ
ィジタル変換器及び一方向性変換器の構造が、圧電体基
板１の上に金属膜を付着させ、更にレジストを付着させ
た後、レジスト膜を露光、現像して目的のパターンを得
た後、レジストに被われていない部分の金属膜をエッチ
ングなどにより除去した後、レジストの端面のレジスト
に被われていない部分の金属膜を陽極酸化などにより誘
電体化した後、新たに金属膜を付着させた後、リフトオ
フ法を用いて、レジスト膜上の金属膜を除去して得られ
る、電極間を誘電体で分離した構造の両方向性のインタ
ーディジタル電極及び一方向性変換器からなる構造の弾
性表面波フィルタを得ることにより、低挿入損失のフィ
ルタが得られる。In claim 1, the structure of the bidirectional interdigital transducer and the unidirectional transducer includes depositing a metal film on a piezoelectric substrate 1, further depositing a resist, and then removing the resist film. After exposing and developing to obtain the desired pattern, remove the metal film on the part not covered by the resist by etching, etc., and then remove the metal film in the part of the end face of the resist not covered by the resist by anodizing etc. Bidirectional interdigital with a structure in which the electrodes are separated by a dielectric material, which is obtained by converting the resist film into a dielectric material, attaching a new metal film, and then removing the metal film on the resist film using a lift-off method. By obtaining a surface acoustic wave filter having a structure consisting of an electrode and a unidirectional transducer, a filter with low insertion loss can be obtained.
この場合、両方向性のインターディジタル電極は、通常
の方法で作製された構造、或いは一方向性変換器が通常
の方法で作製された一方向性変換器を用いた弾性表面波
フィルタも本発明に含まれるものとする。In this case, the bidirectional interdigital electrode may have a structure fabricated by a conventional method, or the unidirectional transducer may be a surface acoustic wave filter using a unidirectional transducer fabricated by a conventional method. shall be included.
特許請求の範囲第１項、第２項において、一方向性変換
器として、第２図のように、浮き電極を持つ一方向性変
換器、この場合の電極幅は、第２図において、右からほ
ぼ２λ／５の正電極８、 ほぼ４λ／５の負電極９、ほ
ぼ２λ／５の浮き電極１０、ほぼ２λ／５の負電極９を
一周期とする電極構造の浮き電極をもつ一方向性変換器
、或いは、これらの電極幅か＋５０％から一５０％の範
囲にある浮き電極をもつ一方向性変換器を用いることに
より低挿入損失の弾性表面波フィルタが得られる。In claims 1 and 2, the unidirectional transducer is a unidirectional transducer having a floating electrode as shown in FIG. One direction with a floating electrode having an electrode structure in which one period includes a positive electrode 8 of approximately 2λ/5, a negative electrode 9 of approximately 4λ/5, a floating electrode 10 of approximately 2λ/5, and a negative electrode 9 of approximately 2λ/5. A surface acoustic wave filter with low insertion loss can be obtained by using a unidirectional transducer or a unidirectional transducer with floating electrodes whose electrode widths range from +50% to -50%.
特許請求の範囲第１項、第２項、第３項において、中心
にある両方向性のインターディジタル電極２が第３図の
ように、周波数に対して、所望の位相、振幅特性をもつ
ように重み付けされた構造の両方向性のインターディジ
タル電極ＩＩを用いることにより、所望の特性をもつ低
挿入損失の弾性表面波フィルタが得られる。この場合、
重み付け法は、これまでに得られているいずれかの方法
を用いた場合も本発明に含まれるものとする。In claims 1, 2, and 3, the bidirectional interdigital electrode 2 at the center has desired phase and amplitude characteristics with respect to frequency, as shown in FIG. By using bidirectional interdigital electrodes II with a weighted structure, a low insertion loss surface acoustic wave filter with desired characteristics is obtained. in this case,
The present invention also includes the use of any of the weighting methods that have been developed so far.
特許請求の範囲第１項、第２項、第３項、第４項１．二
おいて、両側の一方向性変換器の位置が両方向性インタ
ーディジタル変換器の中心から一方向性変換器の中心ま
での距離が左右で同じ距離である構造、或いは数波長分
異なる構造、或いは両側の一方向性変換器の対数が同じ
構造、或いは異なる構造の一方向性変換器を用いること
により低挿入損失の所望の特性をもつ弾性表面波フィル
タが得られる。Claims 1, 2, 3, and 4 1. 2, the positions of the unidirectional transducers on both sides have a structure in which the distance from the center of the bidirectional interdigital converter to the center of the unidirectional transducer is the same distance on the left and right sides, or a structure in which the positions differ by several wavelengths, or By using unidirectional transducers on both sides having the same logarithm or different structures, a surface acoustic wave filter having the desired characteristic of low insertion loss can be obtained.
特許請求の範囲第１項、第２項、第３項、第４項、第５
項において、一方向性変換器が重み付けされた構造の一
方向性変換器を用いることにより所望の特性をもつ低挿
入損失の弾性表面波フィルタが得られる。Claims 1, 2, 3, 4, and 5
In Section 1, a surface acoustic wave filter with desired characteristics and low insertion loss can be obtained by using a unidirectional transducer having a weighted structure.
以上は、弾性表面波フィルタについて述べたが、上記の
構造を用いた弾性表面波デバイス、弾性波デバイス、或
いは電子通信デバイスも本特許に含まれるものとする。Although a surface acoustic wave filter has been described above, surface acoustic wave devices, acoustic wave devices, or electronic communication devices using the above structure are also included in this patent.
第１図は、本発明の一方向性変換器を用いた弾性表面波
フィルタの鳥観図である。
１・・圧電体基板、２・・・両方向性のインターディジ
タル電極、３・・・グループ型一方向性変換器、４・・
グループ型一方向性変換器、５・・方向性の方向、６・
・両側の一方向性変換器を電気的に接続するための電極
、７・・・両側の一方向性変換器を電気的に接続するた
めの電極、
第２図（ａ）、（ｂ）は、浮き電極一方向性変換器の平
面図、及び断面図である。
８・・・正電極、９・・・負電極、１０ ・浮き電極、
第３図は両方向性の重み付けインターディジタル変換器
の平面図である。
＋ｉ・・・重み付けインタープ、ジタル変換器の正電極
、１２・・負電極、FIG. 1 is a bird's-eye view of a surface acoustic wave filter using the unidirectional transducer of the present invention. 1... Piezoelectric substrate, 2... Bidirectional interdigital electrode, 3... Group type unidirectional transducer, 4...
Group type unidirectional transducer, 5. Directional direction, 6.
- Electrodes for electrically connecting the unidirectional transducers on both sides, 7... Electrodes for electrically connecting the unidirectional transducers on both sides, Figures 2 (a) and (b) , a plan view and a cross-sectional view of a floating electrode unidirectional transducer. 8... Positive electrode, 9... Negative electrode, 10 - Floating electrode,
FIG. 3 is a top view of a bidirectional weighted interdigital converter. +i...Weighting interp, positive electrode of digital converter, 12...Negative electrode,
Claims (6)
ーディジタル電極を配置して弾性表面波を励振、受信す
る構造の弾性表面波フィルタにおいて、中心に両方向性
のインターディジタル電極を配置し、その両側に、中心
方向に方向性５をもつグループ型の一方向性変換器３、
４、或いは３−位相型の一方向性変換器を配置し、両側
の一方向性変換器の信号が同位相で加わるように電極６
、７を用いて両変換器を接続した構造の一方向性変換器
を用いた弾性表面波フィルタ。(1) As shown in Fig. 1, a surface acoustic wave filter has a structure in which interdigital electrodes are arranged on a piezoelectric substrate 1 to excite and receive surface acoustic waves, and a bidirectional interdigital electrode is placed in the center. arranged, and on both sides thereof, a group type unidirectional transducer 3 having directionality 5 in the center direction,
4 or 3-phase type unidirectional transducers are arranged, and the electrodes 6 are arranged so that the signals from the unidirectional transducers on both sides are applied in the same phase.
, 7 is used to connect both transducers.
性のインターディジタル変換器、及び両側の一方向性変
換器の構造が、圧電体の上に金属膜を付着させた後、更
にレジストを付着させた後、目的とするマスクを用いて
露光、現像した後、レジストに被われていない部分の金
属膜をエッチングなどにより除去した後、レジストの端
面下のレジストに被われていない部分の金属膜を陽極酸
化などにより誘電体化した後、新たに金属膜を付着させ
た後、リフトオフ法を用いて、レジスト膜上の金属膜を
除去して得られる、電極間を誘電体で分離した構造の両
方向性のインターディジタル変換器及び一方向性変換器
からなる構造の一方向性変換器を用いた弾性表面波フィ
ルタ。この場合、いずれか一方は、通常の方法で作製さ
れた弾性表面波変換器の場合も本発明に含まれる。(2) In claim 1, the structure of the bidirectional interdigital transducer in the center and the unidirectional transducers on both sides is formed by depositing a metal film on the piezoelectric body and then further applying a resist. After depositing, exposing and developing the metal film using the desired mask, removing the metal film in the part not covered by the resist by etching, etc. A structure in which the electrodes are separated by a dielectric material, which is obtained by converting the film into a dielectric material by anodizing, etc., then attaching a new metal film, and then removing the metal film on the resist film using a lift-off method. A surface acoustic wave filter using a unidirectional transducer with a structure consisting of a bidirectional interdigital transducer and a unidirectional transducer. In this case, the present invention also includes the case where one of the transducers is a surface acoustic wave transducer manufactured by a conventional method.
向性変換器として、第２図のように、浮き電極を持つ一
方向性変換器、この場合の電極幅は、第２図において、
右からほぼ２λ／５（λは弾性表面波の２倍高調波の波
長）の正電極８、ほぼ４λ／５の負電極９、ほぼ２λ／
５の浮き電極１０、ほぼ２λ／５の負電極９を一周期と
する電極構造の浮き電極をもつ一方向性変換器、或いは
、これらの電極幅が＋５０％から−５０％の範囲にある
浮き電極をもつ一方向性変換器を用いた弾性表面波フィ
ルタ。(3) In claims 1 and 2, the unidirectional transducer is a unidirectional transducer having a floating electrode as shown in FIG. In,
From the right, the positive electrode 8 has a width of approximately 2λ/5 (λ is the wavelength of the second harmonic of the surface acoustic wave), the negative electrode 9 has a width of approximately 4λ/5, and the negative electrode 9 has a width of approximately 2λ/5.
A unidirectional transducer with a floating electrode having an electrode structure in which one period is a floating electrode 10 of 5 and a negative electrode 9 of approximately 2λ/5, or a floating whose electrode width is in the range of +50% to -50%. A surface acoustic wave filter using a unidirectional transducer with electrodes.
て、中心にある両方向性のインターディジタル電極２を
、第３図のように、周波数に対して、所望の位相、振幅
特性をもつように重み付けされた構造の両方向性の正電
極１１と負電極１２からなるインターディジタル電極と
し、かつ第１図のように、両側に一方向性変換器を用い
た弾性表面波フィルタ。この場合、重み付け法として、
これまでに得られているいずれかの方法を用いた場合も
本発明に含まれるものとする。(4) In claims 1, 2, and 3, the central bidirectional interdigital electrode 2 has desired phase and amplitude characteristics with respect to frequency, as shown in FIG. A surface acoustic wave filter is an interdigital electrode consisting of a bidirectional positive electrode 11 and a negative electrode 12 weighted so as to have a weighted structure, and uses unidirectional transducers on both sides as shown in FIG. In this case, the weighting method is
The present invention also includes the use of any of the methods obtained so far.
項において、両側の一方向性変換器の位置が両方向性イ
ンターディジタル変換器の中心から、一方向性変換器の
中心までの距離が右と左で同じ距離である構造、或いは
数波長分異なる構造、或いは両側の一方向性変換器の対
数が同じ構造、或いは異なる構造の一方向性変換器を用
いた弾性表面波フィルタ。(5) Claims 1, 2, 3, and 4
In Section 1, the position of the unidirectional transducers on both sides is the same distance from the center of the bidirectional interdigital transducer to the center of the unidirectional transducer on the right and left, or the structure differs by several wavelengths. , or a surface acoustic wave filter using unidirectional transducers with the same or different logarithms on both sides.
項、第５項において、一方向性変換器が重み付けされた
構造の一方向性変換器を用いた弾性表面波フィルタ。(6) Claims 1, 2, 3, and 4
5. A surface acoustic wave filter using a unidirectional transducer having a structure in which the unidirectional transducer is weighted.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6504889A JPH02244811A (en) | 1989-03-16 | 1989-03-16 | Surface acoustic wave filter using unidirectional converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6504889A JPH02244811A (en) | 1989-03-16 | 1989-03-16 | Surface acoustic wave filter using unidirectional converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02244811A true JPH02244811A (en) | 1990-09-28 |
Family
ID=13275686
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6504889A Pending JPH02244811A (en) | 1989-03-16 | 1989-03-16 | Surface acoustic wave filter using unidirectional converter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02244811A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5909157A (en) * | 1994-10-31 | 1999-06-01 | Ngk Insulators, Ltd. | Surface acoustic wave filter device and transducer therefor having unidirectional and bidirectional structures |
| JP2006261744A (en) * | 2005-03-15 | 2006-09-28 | Epson Toyocom Corp | Transversal saw filter |
| KR100812064B1 (en) * | 2006-09-08 | 2008-03-07 | 에스케이 텔레콤주식회사 | Surface acoustic wave filter of transmitting signal two direction |
| US10045746B2 (en) | 2014-03-10 | 2018-08-14 | Fujifilm Corporation | Radiation image processing apparatus, method, and medium |
-
1989
- 1989-03-16 JP JP6504889A patent/JPH02244811A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5909157A (en) * | 1994-10-31 | 1999-06-01 | Ngk Insulators, Ltd. | Surface acoustic wave filter device and transducer therefor having unidirectional and bidirectional structures |
| US6127904A (en) * | 1994-10-31 | 2000-10-03 | Ngk Insulators, Ltd. | Surface acoustic wave filter having unidirectional and bidirectional transducers |
| JP2006261744A (en) * | 2005-03-15 | 2006-09-28 | Epson Toyocom Corp | Transversal saw filter |
| KR100812064B1 (en) * | 2006-09-08 | 2008-03-07 | 에스케이 텔레콤주식회사 | Surface acoustic wave filter of transmitting signal two direction |
| US10045746B2 (en) | 2014-03-10 | 2018-08-14 | Fujifilm Corporation | Radiation image processing apparatus, method, and medium |
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