JPH0685492B2 - Surface acoustic wave resonator - Google Patents
Surface acoustic wave resonatorInfo
- Publication number
- JPH0685492B2 JPH0685492B2 JP6262986A JP6262986A JPH0685492B2 JP H0685492 B2 JPH0685492 B2 JP H0685492B2 JP 6262986 A JP6262986 A JP 6262986A JP 6262986 A JP6262986 A JP 6262986A JP H0685492 B2 JPH0685492 B2 JP H0685492B2
- Authority
- JP
- Japan
- Prior art keywords
- acoustic wave
- surface acoustic
- wave resonator
- mode
- width
- 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
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、弾性表面波共振子の交差指状電極の形状に関
する。本発明は、横モードスプリアスの抑圧効果のよい
弾性表面波共振子に利用される。The present invention relates to the shape of interdigital electrodes of a surface acoustic wave resonator. INDUSTRIAL APPLICABILITY The present invention is used for a surface acoustic wave resonator having a good effect of suppressing transverse mode spurious.
本発明は、圧電基板上に少なくとも１組の交差指状電極
が形成された弾性表面波共振子において、 交差指状電極子の相互に交差する電極指の開口長に対す
る交差幅の比を0.65ないし0.75とし、かつ１組の交差指
状電極においてこの交差幅を一定とすることにより、 弾性表面波共振子の横モードスプリアスを抑圧するとと
もに、その設計時の自由度を大きくできるのである。According to the present invention, in a surface acoustic wave resonator in which at least one set of interdigital electrodes is formed on a piezoelectric substrate, the cross width ratio of the interdigital electrode elements to the opening length of the electrode fingers crossing each other is 0.65 or more. By setting the cross width to 0.75 and making this cross width constant in one pair of crossed finger electrodes, it is possible to suppress the transverse mode spurious of the surface acoustic wave resonator and to increase the degree of freedom in designing it.
従来、この種の弾性表面波共振子は共振周波数近傍に生
じる横モードスプリアスを除去するための工夫が必要で
あった。すなわち、第３図に示すように交差指状電極と
グレーティング反射器とのそれぞれの開口長を横モード
スプリアスがカットオフするように狭くする。あるいは
第４図に示すように交差指状電極の各交差指の長さにCO
S関数系の重み付けを行っていた。In the past, this type of surface acoustic wave resonator had to be devised to remove transverse mode spurious near the resonance frequency. That is, as shown in FIG. 3, the opening lengths of the interdigital electrodes and the grating reflector are narrowed so that the transverse mode spurious is cut off. Alternatively, as shown in FIG. 4, CO
The S function system was weighted.
しかし上述した方法では、開口長を狭くするため設計が
制限を受け高性能が得られない。また重み付けをするた
めＱの低下や共振抵抗の増大を招き性能が劣化してしま
う欠点がある。However, in the above-mentioned method, since the opening length is narrowed, the design is limited and high performance cannot be obtained. Further, since weighting is performed, there is a drawback that Q is lowered and resonance resistance is increased, resulting in deterioration of performance.
本発明はこの欠点を解決して、スプリアスを除去するこ
とができ、他の特性に影響を及ぼすことの少ない弾性表
面波共振子を提供することを目的とする。An object of the present invention is to solve this drawback and to provide a surface acoustic wave resonator capable of removing spurious and less affecting other characteristics.
本発明は、圧電基板上に少なくとも１組の交差指状電極
が形成された構成の弾性表面波共振子において、 上記交差指状電極の形状は、電極指の開口長に対する電
極指の交差幅の比が65〜75％の比率であり、この交差幅
が上記交差指状電極内において一定であることを特徴と
する。The present invention provides a surface acoustic wave resonator having a structure in which at least one pair of interdigital electrodes is formed on a piezoelectric substrate, wherein the interdigital electrodes have a shape that is defined by a cross width of the electrode fingers with respect to an opening length of the electrode fingers. The ratio is 65 to 75%, and the width of the intersection is constant in the interdigital electrode.
弾性表面波共振子の横モードスプリアスで問題となるの
は、主たる共振波である０次モードに対する２次モード
のエネルギ分布である。０次モードの波形ピッチに対し
２次モード波形のピッチは小さく、また開口長に対する
交差幅の比率を適当にとると、０次モード波形の一つの
ピッチの間で、２次モード波形のプラス極側とマイナス
極側の面積がほぼ等しくすることができる。この場合主
たる共振波である０次モードの１ピッチに対して、２次
モードの発生エネルギはほぼ相殺されるので、この２次
モードによる波形は励振あるいは受信されない。The problem of the transverse mode spurious of the surface acoustic wave resonator is the energy distribution of the secondary mode with respect to the 0th mode which is the main resonance wave. The pitch of the secondary mode waveform is small with respect to the waveform pitch of the zeroth-order mode, and if the ratio of the cross width to the aperture length is set to an appropriate value, the positive pole of the secondary mode waveform will be between one pitch of the zeroth-order mode waveform. The areas on the negative side and the negative side can be made substantially equal. In this case, since the generated energy of the secondary mode is almost canceled with respect to one pitch of the 0th-order mode which is the main resonance wave, the waveform of this secondary mode is not excited or received.
次に、本発明の一実施例について図面を参照して説明す
る。Next, an embodiment of the present invention will be described with reference to the drawings.
第１図は本発明の一実施例の平面図である。第１図にお
いて、圧電基板11上には、中央に１組の交差指状電極12
が形成され、その左右にはブレーティング反射器13、14
が配置されている。FIG. 1 is a plan view of an embodiment of the present invention. In FIG. 1, on the piezoelectric substrate 11, a pair of interdigital electrodes 12 is provided at the center.
Are formed on the left and right sides of the
Are arranged.
ここに本発明の特徴とするところは、交差指状電極12に
おいて、交差幅l2は開口長l1に対して l2／l1≒0.7 になるように形成されたことにある。The feature of the present invention lies in that the cross finger-shaped electrode 12 is formed such that the cross width l 2 is l 2 / l 1 ≈0.7 with respect to the opening length l 1 .
弾性表面波共振子の横モードスプリアスとして問題にな
るのが、０次モードのものに対し２次モードのものであ
り、共振子の横方向のエネルギ分布は第２図の波形22の
ような分布をしている。第２図でわかるように、交差幅
l2に対する領域幅W0を、開口長l1に対する領域幅Ｗの約
70％にとると、波形22の斜線部が示すように、電荷的に
プラスとマイナスとが打ち消され、２次モードは励振ま
たは受信されなくなる。このとき主たる共振子である０
次モードは第２図の波形21で示すように、エネルギ分布
の二重斜線部で示す部分以外のすそ野のみが励振または
受信されなくなるだけであるので、ほとんど影響を受け
ないことになる。The problem as the transverse mode spurious of the surface acoustic wave resonator is that it is the second-order mode as opposed to the 0th-order mode. Are doing As you can see in Figure 2, the crossing width
The area width W 0 for l 2 is approximately the area width W for the opening length l 1 .
At 70%, as indicated by the shaded area of the waveform 22, positive and negative charges are canceled out, and the secondary mode is not excited or received. At this time, 0 which is the main resonator
As shown by the waveform 21 in FIG. 2, the next mode is hardly affected because only the skirts other than the part indicated by the double-hatched portion of the energy distribution are not excited or received.
以上説明したように、本発明では、開口長と交差幅の比
率による制限を受けるだけであるので、設計に際して従
来に比べ大きな自由度が得られる効果がある。As described above, the present invention is limited only by the ratio of the opening length and the cross width, and therefore has the effect of providing a greater degree of freedom in designing than in the past.
さらに重み付けする必要もないので、Ｑの低下や共振抵
抗の増大などがなく弾性表面波共振子の高性能化を容易
に実現できる。Further, since it is not necessary to perform weighting, it is possible to easily realize high performance of the surface acoustic wave resonator without lowering Q or increasing resonance resistance.
第１図は本発明一実施例の平面図。 第２図は０次および２次の横モードのエネルギ分布を示
す図。 第３図は従来の弾性表面波共振子の平面図。 第４図は従来の他の弾性表面波共振子の平面図。 11、31、41……圧電性基板、12、32、42……交差指状電
極、13、14、33、34、43、44……グレーティング反射
器、21……０次の横モードの波形、22……２次の横モー
ドの波形、l1……開口長、l2……交差幅、Ｗ……l1に対
する領域幅、W0……l2に対する領域幅。FIG. 1 is a plan view of an embodiment of the present invention. FIG. 2 is a diagram showing energy distributions of 0th-order and 2nd-order transverse modes. FIG. 3 is a plan view of a conventional surface acoustic wave resonator. FIG. 4 is a plan view of another conventional surface acoustic wave resonator. 11, 31, 41 ...... Piezoelectric substrate, 12, 32, 42 …… Interdigitated electrodes, 13, 14, 33, 34, 43, 44 …… Grating reflector, 21 …… 0th-order transverse mode waveform , 22 …… Second-order transverse mode waveform, l 1 …… Aperture length, l 2 …… Cross width, W …… l 1 region width, W 0 …… l 2 region width.
Claims (1)
極が形成された構成の弾性表面波共振子において、 上記交差指状電極の形状は、電極指の開口長に対する電
極指の交差幅の比が65〜75％の比率であり、 この交差幅が上記交差指状電極内において一定である ことを特徴とする弾性表面波共振子。1. A surface acoustic wave resonator having a structure in which at least one set of interdigitated electrodes is formed on a piezoelectric substrate, wherein the interdigitated electrodes have a shape in which a crossing width of the electrode fingers with respect to an opening length of the electrode fingers. The surface acoustic wave resonator is characterized in that the crossing width is constant in the interdigital electrode, and the crossing width is 65 to 75%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6262986A JPH0685492B2 (en) | 1986-03-19 | 1986-03-19 | Surface acoustic wave resonator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6262986A JPH0685492B2 (en) | 1986-03-19 | 1986-03-19 | Surface acoustic wave resonator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62219709A JPS62219709A (en) | 1987-09-28 |
| JPH0685492B2 true JPH0685492B2 (en) | 1994-10-26 |
Family
ID=13205804
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6262986A Expired - Lifetime JPH0685492B2 (en) | 1986-03-19 | 1986-03-19 | Surface acoustic wave resonator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0685492B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09260996A (en) * | 1996-03-19 | 1997-10-03 | Nec Corp | Surface acoustic wave device |
| JP2982864B2 (en) * | 1996-10-14 | 1999-11-29 | 日本電気株式会社 | Surface acoustic wave device |
| JP4003511B2 (en) | 2002-04-04 | 2007-11-07 | 株式会社村田製作所 | Longitudinal coupled resonator type surface acoustic wave device |
-
1986
- 1986-03-19 JP JP6262986A patent/JPH0685492B2/en not_active Expired - Lifetime
Non-Patent Citations (1)
| Title |
|---|
| 山本泰司他「弾性表面波共振子」電子通信学会技術研究報告ＵＳ８４ー１５Ｐ．７５ |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62219709A (en) | 1987-09-28 |
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