JP3355039B2 - Surface acoustic wave device - Google Patents
Surface acoustic wave deviceInfo
- Publication number
- JP3355039B2 JP3355039B2 JP18644194A JP18644194A JP3355039B2 JP 3355039 B2 JP3355039 B2 JP 3355039B2 JP 18644194 A JP18644194 A JP 18644194A JP 18644194 A JP18644194 A JP 18644194A JP 3355039 B2 JP3355039 B2 JP 3355039B2
- Authority
- JP
- Japan
- Prior art keywords
- bus bar
- surface acoustic
- acoustic wave
- ground
- reflector
- 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
Landscapes
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、弾性表面波デバイスの
電極構造を変えて特性を改善することに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improving the characteristics of a surface acoustic wave device by changing the electrode structure.
【０００２】[0002]
【従来の技術】従来から、トランスデューサ及び反射器
の対向するバスバーの間隔は、一般的に使用周波数の波
長λの整数倍が使用されていた。2. Description of the Related Art Conventionally, an interval between a bus bar facing a transducer and a reflector is generally an integer multiple of a wavelength λ of a working frequency.
【０００３】[0003]
【発明が解決しようとする課題】しかし、従来技術の方
法では、トランスデューサ及び反射器の対向するバスバ
ーの間隔が、一般的に使用周波数の波長λの整数倍であ
るために、横モードの弾性表面波の定在波がたつこと等
により、横モードの弾性表面波によるスプリアスが発生
するという課題があった。However, in the prior art method, since the distance between the opposing bus bars of the transducer and the reflector is generally an integral multiple of the wavelength λ of the working frequency, the elastic surface of the transverse mode is not used. There has been a problem that spurious due to a surface acoustic wave in a transverse mode is generated due to a standing wave of the wave.
【０００４】[0004]
【課題を解決するための手段】前記課題を解決するため
には、圧電基板上に、入力又は出力端子と接続されるバ
スバーと、接地に接続されるバスバーとを形成し、各々
のバスバーに櫛歯状に対向する電極指を所定の間隔で形
成し、少なくとも２つ以上のトランスデューサを設けた
弾性表面波デバイス、又は、このトランスデューサに対
する反射器を設けた弾性表面波デバイスにおいて、トラ
ンスデューサの対向する入力又は出力端子と接続される
バスバーと、接地に接続されるバスバーとの間隔Ｌ、及
び反射器の対向するバスバーの間隔Ｌが、｛（ｎ＋０．
４２５）λ｝乃至｛（ｎ＋０．８２５）λ｝（但し、ｎ
は整数、λは使用周波数の波長）であること。又は、前
記弾性表面波デバイスにおいて、トランスデューサの対
向する入力又は出力端子と接続されるバスバーと、接地
に接続されるバスバーとの間隔Ｌか、反射器の対向する
バスバーの間隔Ｌかのどちらかが、｛（ｎ＋０．４２
５）λ｝乃至｛（ｎ＋０．８２５）λ｝（但し、ｎは整
数、λは使用周波数の波長）であることによって、トラ
ンスデューサ及び反射器の対向するバスバーの間に、横
モードの弾性表面波の定在波が発生することを防止する
ことができ、前記課題を解決することができた。 In order to solve the above-mentioned problems, a bus connected to an input or output terminal is provided on a piezoelectric substrate.
And a bus bar connected to the ground.
Electrode fingers facing each other in a comb-teeth shape at predetermined intervals
And provided at least two or more transducers
For surface acoustic wave devices or transducers
Surface acoustic wave device provided with a reflector
Connected to the opposite input or output terminal of the transducer
The distance L between the bus bar and the bus bar connected to the ground, and
The distance L between the bus bars facing the reflector and the reflector is ｛(n + 0.
425) λ} to {(n + 0.825) λ} (where n
Is an integer, and λ is the wavelength of the operating frequency. Or before
In the surface acoustic wave device, a pair of transducers is used.
Bus bar connected to the input or output terminal
The distance L between the bus bar and the reflector
Either of the busbar intervals L is ｛(n + 0.42
5) λ} to {(n + 0.825) λ} (where n is an integer)
(Λ is the wavelength of the operating frequency) to prevent the generation of a standing wave of the surface acoustic wave in the transverse mode between the opposing bus bars of the transducer and the reflector.
Thus, the above problem could be solved.
【０００５】[0005]
（実施例１）図１に本発明の第１の実施例の電極パター
ンを示す。図１の実施例は圧電基板上に入力又は出力側
トランスデューサとして入力又は出力端子と接続される
バスバー１、接地側バスバー２を有す。また、該入力又
は出力端子に接続されるバスバー１は入力又は出力側電
極指３と接地側電極４とがそれぞれ所定の間隔を保持し
て対向している。ここで対向している該入力又は出力端
子と接続されるバスバー１と該接地側バスバー２の間隔
Ｌ1は、使用周波数の波長λの整数倍と一致しない様に
選ぶ。 即ち、Ｌ1≠ｎ・λ とする。 （ｎは整数） 実験によれば、Ｌ1を（ｎ＋５／８）λに選定した時、
最も良好な結果が得られた。なお、Ｌ1を（ｎ＋５／
８）λすなわち、（ｎ＋０．６２５）λを中心に（ｎ＋
０．４２５）λ〜（ｎ＋０．８２５）λの間で有ればス
ブリアス特性が改善され良好な結果が得られることがわ
かった。(Embodiment 1) FIG. 1 shows an electrode pattern according to a first embodiment of the present invention. The embodiment of FIG. 1 has a bus bar 1 and a ground bus bar 2 connected to input or output terminals as input or output transducers on a piezoelectric substrate. In addition, the bus bar 1 connected to the input or output terminal has the input or output electrode finger 3 and the ground electrode 4 facing each other with a predetermined space therebetween. Here opposite bus bar 1 and spacing L 1 of the ground side bus bar 2 connected to the input or output terminals are are chosen so as not to coincide with an integral multiple of the wavelength λ of the operating frequency. That is, L 1 ≠ n · λ. (N is an integer) According to experiments, when L 1 is selected to be (n + 5/8) λ,
The best results were obtained. In addition, the L 1 (n + 5 /
8) λ That is, (n + 0.625) λ is centered on (n +
0.425) λ to (n + 0.825) λ, it was found that the spurious characteristics were improved and good results were obtained.
【０００６】なお、トランスデューサの入力側を示した
が、トランスデューサの出力側についても、同様であ
る。Although the input side of the transducer is shown, the same applies to the output side of the transducer.
【０００７】（実施例２）図２に本発明の実施例の反射
器電極パターンを示す。図２の実施例は前記トランスデ
ューサに対応する反射器においては、対向するバスバー
５の間に所定の間隔の櫛状の電極で接続されている。こ
こで対向するバスバーの間隔Ｌ2は、使用周波数の波長
λの整数倍と一致しない様に選ぶ。即ち、Ｌ2≠ｎ・λ
とする。実験によれば、Ｌ2を（ｎ＋５／８）λに選定
することにより最も良好な結果が得られた。なお、Ｌ2
を（ｎ＋５／８）λすなわち、（ｎ＋０．６２５）λを
中心に（ｎ＋０．４２５）λ〜（ｎ＋０．８２５）λの
間で有ればスプリアス特性が改善され良好な結果が得ら
れることがわかった。(Embodiment 2) FIG. 2 shows a reflector electrode pattern according to an embodiment of the present invention. In the embodiment shown in FIG. 2, the reflectors corresponding to the transducers are connected by comb-shaped electrodes at predetermined intervals between the bus bars 5 facing each other. Wherein spacing of the busbar which faces L 2 are chosen so as not to coincide with an integral multiple of the wavelength λ of the operating frequency. That is, L 2 ≠ n · λ
And Experiments have shown that the best results are obtained by choosing L 2 to be (n + 5/8) λ. Note that L 2
Is (n + 5/8) λ, that is, if (n + 0.425) λ to (n + 0.825) λ centered on (n + 0.625) λ, the spurious characteristics can be improved and good results can be obtained. all right.
【０００８】なお、実施例ではトランスデューサと反射
器の双方に実施しているが、どちらか片方だけの実施に
おいても従来の波長の整数倍の間隔とした時よりも、横
モードスプリアスの悪影響は軽減できる。図４に弾性表
面波デバイスの通過域の特性を示す。図４（ａ）は、本
発明の実施例１と実施例２を実施した場合の通過域の特
性を示す。図４（ｂ）は、従来技術の通過域の特性を示
す。図４（ｂ）の○で囲んで示した約１ｄＢのリップル
は、入力又は出力端子に接続されるバスバーと接地側バ
スバーの間に横モードの定在波がたった結果であり、図
４（ａ）の本発明の実施により，この入力又は出力端子
に接続されるバスバーと接地側バスバーの間及び反射器
に横モードの定在波のたつことを防止した結果、通過域
の特性の○で囲んで示した通り約０．２ｄＢのリップル
に改善されている。In the embodiment, the operation is performed on both the transducer and the reflector. However, the effect of the transverse mode spurious is reduced even when only one of them is used, as compared with the case where the interval is an integral multiple of the conventional wavelength. it can. FIG. 4 shows the passband characteristics of the surface acoustic wave device. FIG. 4A shows the characteristics of the passband when the first and second embodiments of the present invention are implemented. FIG. 4B shows the characteristics of the passband of the related art. The ripple of about 1 dB indicated by circles in FIG. 4B is a result of the standing wave in the transverse mode between the bus bar connected to the input or output terminal and the bus bar on the ground side. According to the implementation of the present invention, the standing wave in the transverse mode is prevented from being applied between the bus bar connected to the input or output terminal and the ground-side bus bar and to the reflector. As shown in the figure, the ripple is improved to about 0.2 dB.
【０００９】[0009]
【発明の効果】本発明により、トランスデューサにおい
ては入力又は出力端子に接続されるバスバー及び接地側
バスバーからなる一対のバスバーの対向する間隔Ｌ
1を、使用周波数の波長λの整数倍と一致しない様に選
ぶことにより、対向するそれぞれの一対のバスバーの間
に横モードの弾性表面波の定在波がたつことを防止出来
るため、横モードスプリアスによる弾性表面波デバイス
への特性上の悪影響を防ぐことができるという効果が実
現出来た。また反射器における対向する一対のバスバー
の間隔Ｌ2を使用周波数の波長λの整数倍と一致しない
様に選ぶことにより、バスバー間の横モードの弾性表面
波のたつのを防止出来特性を向上させることが出来た。
さらに、入出力端子と接続するバスバーと接地側バスバ
ーの間隔Ｌ1と反射器の一対のバスバーの間隔Ｌ2をもと
に使用周波数の波長λの整数倍と一致させない様にし
て、横モードの弾性表面波の定在波のたつのを防止し、
リップル特性を向上させることが出来た。According to the present invention, in a transducer, a distance L between a pair of bus bars composed of a bus bar connected to an input or output terminal and a ground-side bus bar.
For 1, by choosing so as not to coincide with an integral multiple of the wavelength λ of the operating frequency, can be prevented from standing waves of the surface acoustic wave in the transverse mode passes between each pair of bus bars opposing transverse mode The effect of being able to prevent adverse effects on characteristics of the surface acoustic wave device due to spurious components was achieved. Moreover by choosing so as not to coincide with an integral multiple of the wavelength λ of the frequency using distance L 2 of the pair of bus bars facing the reflector, to improve the prevention can characteristic stand of the surface acoustic wave of the transverse mode between the bus bars Was completed.
Further, in the manner not coincide with an integral multiple of the wavelength λ of the original use frequency spacing L 2 of the pair of bus bars of the reflector and the bus bar to be connected to the output terminal and the distance L 1 of the ground side bus bar, the transverse mode Prevents the standing wave of surface acoustic waves,
The ripple characteristics could be improved.
【図１】図１は、本発明のトランスデューサの一部を示
す平面図である。FIG. 1 is a plan view showing a part of a transducer according to the present invention.
【図２】図２は、本発明の反射器の一部を示す平面図で
ある。FIG. 2 is a plan view showing a part of the reflector of the present invention.
【図３】図３は、一般的な弾性表面波デバイスの電極構
成を示す図である。FIG. 3 is a diagram showing an electrode configuration of a general surface acoustic wave device.
【図４】図４（ａ）本発明のリップル特性を示すグラ
フ。 図４（ｂ）従来技術のリップル特性を示すグラフ。FIG. 4 (a) is a graph showing the ripple characteristics of the present invention. FIG. 4B is a graph showing the ripple characteristics of the related art.
１ 入力又は出力端子に接続されるバスバー ２ 接地側バスバー ３ 入力又は出力側櫛型電極 ４ 接地側櫛型電極 ５ 反射器バスバー Reference Signs List 1 bus bar connected to input or output terminal 2 ground-side bus bar 3 input or output-side comb electrode 4 ground-side comb electrode 5 reflector bus bar
フロントページの続き (56)参考文献 特開 昭63−211910（ＪＰ，Ａ) 特開 平５−110371（ＪＰ，Ａ) 特開 平５−95250（ＪＰ，Ａ) 特開 昭63−87007（ＪＰ，Ａ) 特開 平１−282912（ＪＰ，Ａ) 特開 昭58−1316（ＪＰ，Ａ) 特公 平２−60087（ＪＰ，Ｂ２) 特公 平３−36327（ＪＰ，Ｂ２) 米国特許4999535（ＵＳ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) H03H 9/145 Continuation of the front page (56) References JP-A-63-211910 (JP, A) JP-A-5-110371 (JP, A) JP-A-5-95250 (JP, A) JP-A-63-87007 (JP, A) JP-A-1-282912 (JP, A) JP-A-58-1316 (JP, A) JP-B-2-60087 (JP, B2) JP-B-3-36327 (JP, B2) US Patent 4,999,535 (US, A) (58) Field surveyed (Int. Cl. 7 , DB name) H03H 9/145
Claims (1)
されるバスバーと、接地に接続されるバスバーとを形成
し、各々のバスバーに櫛歯状に対向する電極指を所定の
間隔で形成し、少なくとも２つ以上のトランスデューサ
を設けた弾性表面波デバイス、又は該トランスデューサ
に対する反射器を更に設けた弾性表面波デバイスにおい
て、該トランスデューサの対向する該入力又は出力端子
と接続されるバスバーと、該接地に接続されるバスバー
との間隔Ｌ、及び／又は、該反射器の対向するバスバー
の間隔Ｌが、｛（ｎ＋０．４２５）λ｝乃至｛（ｎ＋
０．８２５）λ｝（但し、ｎは整数、λは使用周波数の
波長）であることを特徴とする弾性表面波デバイス。 1. An input or output terminal connected to a piezoelectric substrate
Bus bar connected to ground and bus bar connected to ground
Then, the electrode fingers opposing each other in a comb shape are connected to each bus bar in a predetermined manner.
At least two transducers formed at intervals
Surface acoustic wave device provided with
Surface acoustic wave device further provided with a reflector for
And the opposite input or output terminal of the transducer
Busbar connected to the ground, and busbar connected to the ground
And / or the opposite busbar of the reflector
Are {(n + 0.425) λ} to {(n +
0.825) λ｝ (where n is an integer and λ is the used frequency
Wavelength).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18644194A JP3355039B2 (en) | 1994-07-15 | 1994-07-15 | Surface acoustic wave device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18644194A JP3355039B2 (en) | 1994-07-15 | 1994-07-15 | Surface acoustic wave device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0832401A JPH0832401A (en) | 1996-02-02 |
| JP3355039B2 true JP3355039B2 (en) | 2002-12-09 |
Family
ID=16188507
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18644194A Expired - Lifetime JP3355039B2 (en) | 1994-07-15 | 1994-07-15 | Surface acoustic wave device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3355039B2 (en) |
-
1994
- 1994-07-15 JP JP18644194A patent/JP3355039B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0832401A (en) | 1996-02-02 |
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