JPH0832401A - Surface acoustic wave device - Google Patents
Surface acoustic wave deviceInfo
- Publication number
- JPH0832401A JPH0832401A JP18644194A JP18644194A JPH0832401A JP H0832401 A JPH0832401 A JP H0832401A JP 18644194 A JP18644194 A JP 18644194A JP 18644194 A JP18644194 A JP 18644194A JP H0832401 A JPH0832401 A JP H0832401A
- Authority
- JP
- Japan
- Prior art keywords
- bus bar
- output terminal
- surface acoustic
- input
- 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.)
- 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。FIELD OF THE INVENTION This invention relates to modifying the electrode structure of surface acoustic wave devices to improve their properties.
【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 facing bus bars of a transducer and a reflector is generally an integral multiple of a wavelength λ of a used 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, the distance between the opposing busbars of the transducer and the reflector is generally an integer multiple of the wavelength λ of the frequency used, so that the elastic surface of the transverse mode is There is a problem that spurious waves due to transverse mode surface acoustic waves are generated due to standing waves of waves.
【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、トランスデューサ及び反射器の対向するバスバー
の間隔を、使用周波数の波長λの整数倍にないことによ
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たつことを防
止することにより、前記課題が解決された。In order to solve the above-mentioned problems, the distance between the opposing busbars of the transducer and the reflector is set not to be an integral multiple of the wavelength λ of the used frequency so that the transducer and the reflector face each other. The above problems have been solved by preventing standing waves of surface acoustic waves in the transverse mode from striking between the bus bars.
【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 of a first embodiment of the present invention. The embodiment shown in FIG. 1 has a bus bar 1 and a ground side bus bar 2 connected to an input or output terminal as an input or output side transducer on a piezoelectric substrate. In addition, in the bus bar 1 connected to the input or output terminal, the input or output side electrode finger 3 and the ground side electrode 4 are opposed to each other with a predetermined space therebetween. Here, the interval L 1 between the bus bar 1 connected to the input or output terminal and the ground side bus bar 2 which are opposed to each other is selected so as not to coincide with an integral multiple of the wavelength λ of the used frequency. That is, L 1 ≠ n · λ. (N is an integer) According to the experiment, when L 1 is selected as (n + 5/8) λ,
The best results were obtained. In addition, L 1 is (n + 5 /
8) λ, that is, with (n + 0.625) λ being the center, (n +
It was found that if it was between 0.425) λ and (n + 0.825) λ, 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、Ｌ
2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 reflector of the embodiment shown in FIG. 2, the bus bars 5 facing each other are connected to each other by comb-shaped electrodes having a predetermined distance. Here, the interval L 2 between the opposing bus bars is selected so as not to match an integral multiple of the wavelength λ of the used frequency. That is, L 2 ≠ n · λ
And According to the experiment, the best result was obtained by selecting L 2 as (n + 5/8) λ. Note that L
2 to (n + 5/8) λ, that is, (n + 0.625) λ
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 when the value was between the two.
【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, both the transducer and the reflector are implemented. However, even if only one of them is implemented, the adverse effect of the transverse mode spurious is reduced as compared with the conventional interval of an integral multiple of the wavelength. it can. FIG. 4 shows the characteristics of the pass band of the surface acoustic wave device. FIG. 4A shows the characteristics of the pass band when the first and second embodiments of the present invention are carried out. FIG. 4B shows the characteristics of the pass band of the conventional technique. The ripple of about 1 dB indicated by circles in FIG. 4B is the result of standing wave in the transverse mode between the bus bar connected to the input or output terminal and the ground side bus bar, and FIG. ) Of the present invention, the standing wave of the transverse mode is prevented from standing between the bus bar connected to this input or output terminal and the ground side bus bar and to the reflector. As shown in, 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。As described above, according to the present invention, in the transducer, the distance L between the pair of bus bars connected to the input or output terminals and the ground side bus bar is opposed to each other.
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 that spurious can be prevented from adversely affecting the characteristics of the surface acoustic wave device has been realized. Further, by selecting the distance L 2 between a pair of opposing bus bars in the reflector so as not to be an integer multiple of the wavelength λ of the used frequency, it is possible to prevent the surface acoustic wave in the transverse mode between the bus bars and improve the characteristics. Was completed.
Further, based on the distance L 1 between the bus bar connected to the input / output terminal and the ground side bus bar, and the distance L 2 between the pair of bus bars of the reflector, the number of wavelengths λ of the used frequency is not matched with an integral multiple, and the transverse mode is set. Prevents standing waves of surface acoustic waves,
We were able to improve the ripple characteristics.
【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 of 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 ripple characteristics of the present invention. FIG. 4B is a graph showing ripple characteristics of the conventional technique.
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 1 Bus bar connected to input or output terminal 2 Ground side bus bar 3 Input or output side comb-shaped electrode 4 Ground side comb-shaped electrode 5 Reflector bus bar
Claims (4)
れるバスバーのそれぞれに櫛の歯状に対向する電極指を
所定の間隔で配置し、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において、対向する
該入力又は出力端子と接続されるバスバーと接地側バス
バーの間が、使用周波数の波長λの整数倍と一致しない
間隔としたことを特徴とする弾性表面波デバイス。1. A surface acoustic wave in which at least two or more transducers are provided by disposing electrode fingers facing each other in a comb-teeth shape at predetermined intervals on each bus bar connected to an input or output terminal on a piezoelectric substrate. In the device, the surface acoustic wave device is characterized in that a distance between a bus bar connected to the input terminal or the output terminal facing each other and a ground side bus bar is set so as not to be an integer multiple of a wavelength λ of a used frequency.
れるバスバーと接地側バスバーのそれぞれに櫛の歯状に
対向する電極指を所定の間隔で配置し、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に
おいて、対向する該入力又は出力端子と接続されるバス
バーと接地側バスバーの間隔Ｌが｛ｎ＋（０．４２５〜
０．８２５）｝λ （ｎは整数） であることを特徴とす
る弾性表面波デバイス。2. A bus bar connected to an input or output terminal and a ground-side bus bar on a piezoelectric substrate are provided with electrode fingers facing each other in a comb-teeth shape at predetermined intervals, and at least two or more transducers are provided. In the surface acoustic wave device, the distance L between the bus bar connected to the input terminal or the output terminal facing each other and the ground side bus bar is {n + (0.425-
0.825)} λ (n is an integer).
れるバスバーと接地側バスバーのそれぞれに櫛の歯状に
対向する電極指を所定の間隔で配置し、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に
おいて、対向する該入力又は出力端子と接続されるバス
バーと接地側バスバーの間隔Ｌが（ｎ＋０．６２５）λ
（ｎは整数） であることを特徴とする弾性表面波デバ
イス。3. On a piezoelectric substrate, electrode fingers facing each other in a comb tooth shape are arranged at a predetermined interval on each of a bus bar connected to an input or output terminal and a ground side bus bar, and at least two or more transducers are provided. In the surface acoustic wave device, the distance L between the bus bar connected to the opposing input or output terminal and the ground-side bus bar is (n + 0.625) λ.
The surface acoustic wave device is characterized in that (n is an integer).
おいて、対向するバスバーの間を、使用周波数の波長λ
の整数倍と一致しない間隔としたことを特徴とする特許
請求の範囲第１項又は第２項又は第３項の弾性表面波デ
バイス。4. A reflector for the transducer, wherein a wavelength λ of a used frequency is provided between opposing bus bars.
The surface acoustic wave device according to claim 1, 2 or 3, wherein the interval is not an integer multiple of.
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 true JPH0832401A (en) | 1996-02-02 |
| JP3355039B2 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 |
|---|---|
| JP3355039B2 (en) | 2002-12-09 |
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