JP3202071B2 - Mode-coupled SAW filter - Google Patents
Mode-coupled SAW filterInfo
- Publication number
- JP3202071B2 JP3202071B2 JP22271792A JP22271792A JP3202071B2 JP 3202071 B2 JP3202071 B2 JP 3202071B2 JP 22271792 A JP22271792 A JP 22271792A JP 22271792 A JP22271792 A JP 22271792A JP 3202071 B2 JP3202071 B2 JP 3202071B2
- Authority
- JP
- Japan
- Prior art keywords
- idt
- mode
- wave
- filter
- saw filter
- 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 - Fee Related
Links
Landscapes
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は無線装置などのフィルタ
として使用されるモード結合形ＳＡＷ（弾性表面波）フ
ィルタに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mode-coupling type SAW (Surface Acoustic Wave) filter used as a filter of a radio apparatus or the like.
【０００２】[0002]
【従来の技術】従来のモード結合形ＳＡＷフィルタは、
２つのＩＤＴ（Inter Digital Transducer：交さ指形変
換部）１と３（図２参照）の間隔によって機械的結合を
行っていた。この構成においては、基板上にＩＤＴ形成
後におけるＩＤＴ１と３の間隔の調整はできず、容易な
結合度調整ができなかった。2. Description of the Related Art A conventional mode-coupling type SAW filter includes:
The mechanical coupling is performed by an interval between two IDTs (Inter Digital Transducer: cross-digital converter) 1 and 3 (see FIG. 2). In this configuration, the distance between the IDTs 1 and 3 after the IDT was formed on the substrate could not be adjusted, and the degree of coupling could not be easily adjusted.
【０００３】[0003]
【発明が解決しようとする課題】上述の理由で、従来形
のフィルタは結合度を決定するまでに設計上非常に時間
がかかるという問題点があった。従って、本発明の目的
は、レイリー波（表面波）用の入力部ＩＤＴと出力部Ｉ
ＤＴの間にＳＨ波（Shear Wave) 用ＩＤＴを設け、ＳＨ
波用ＩＤＴに設けたタップの接地によって等価的に入力
部ＩＤＴと出力部ＩＤＴ間の機械的な結合の強さを変更
できるようにし、その結果、基板上にＩＤＴを形成後
も、結合度の調整を容易にし、所望のフィルタ特性が得
られるようにすることにある。For the above reasons, the conventional filter has a problem that it takes a very long time to design the coupling degree. Therefore, an object of the present invention is to provide an input section IDT and an output section I for a Rayleigh wave (surface wave).
An IDT for SH wave (Shear Wave) is provided between DT and SH.
The strength of the mechanical coupling between the input unit IDT and the output unit IDT can be equivalently changed by grounding the tap provided on the wave IDT, and as a result, the coupling degree can be maintained even after the IDT is formed on the substrate. It is to facilitate adjustment and obtain desired filter characteristics.
【０００４】[0004]
【課題を解決するための手段】本発明においては、図１
に例示するように、レイリー波用モード結合形ＳＡＷフ
ィルタの入出力部のＩＤＴ１，３間にＳＨ波用ＩＤＴ５
を設け、機械的に結合したことを特徴とするモード結合
形ＳＡＷフィルタが提供される。また、本発明の他の形
態においては、上述のモード結合形ＳＡＷフィルタにお
いて、ＳＨ波用ＩＤＴ５を多タップに分割し、タップを
選択的に接地し、レイリー波用モード結合形ＳＡＷフィ
ルタの結合度調整を可能にするよう構成される。According to the present invention, FIG.
As shown in FIG. 1, the SHT IDT 5 is provided between the input and output IDTs 1 and 3 of the Rayleigh wave mode-coupled SAW filter.
And a mode-coupled SAW filter characterized by being mechanically coupled. In another mode of the present invention, in the above-described mode-coupled SAW filter, the SHT IDT 5 is divided into multiple taps, the taps are selectively grounded, and the degree of coupling of the Rayleigh-wave mode-coupled SAW filter is increased. It is configured to allow for adjustment.
【０００５】[0005]
【作用】上述のモード結合形ＳＡＷフィルタを用いれ
ば、２つのＩＤＴ１，３上を伝わる表面波（レイリー
波）に対し直角方向に伝わるＳＨ波（Shear Wave) を利
用して、入出力部のＩＤＴ１，３を機械的に結合でき
る。また、ＳＨ波用のＩＤＴ５にタップを設けて、タッ
プを必要に応じて接地することによって、ＩＤＴ１，３
の間の結合度を変えることができる。When the above-described mode-coupling type SAW filter is used, the SHT (Shear Wave) propagating in a direction perpendicular to the surface wave (Rayleigh wave) propagating on the two IDTs 1 and 3 is used to control the IDT1 of the input / output section. , 3 can be mechanically coupled. A tap is provided on the IDT 5 for the SH wave, and the tap is grounded as necessary, so that the IDTs 1 and 3 are provided.
Can be varied.
【０００６】[0006]
【実施例】本発明の一実施例としてのモード結合形ＳＡ
Ｗフィルタの構成が図１に示される。図のような電極構
成は例えば水晶に対し金またはアルミニウムを蒸着して
得られる。このモード結合形フィルタは、レイリー波用
モード結合形ＳＡＷフィルタの入力部ＩＤＴ１、同じく
出力部ＩＤＴ３、入力部ＩＤＴ１の両側（レイリー波の
伝搬方向）に設けられた反射器２、出力部ＩＤＴ３の両
側（レイリー波の伝搬方向）に設けられた反射器４、お
よびＩＤＴ１と３の間に設けられたＳＨ波用ＩＤＴ５を
具備する。DESCRIPTION OF THE PREFERRED EMBODIMENTS Mode-coupled SA as an embodiment of the present invention
The configuration of the W filter is shown in FIG. The electrode configuration as shown in the figure is obtained, for example, by depositing gold or aluminum on quartz. The mode-coupled filter includes an input part IDT1, an output part IDT3, a reflector 2 provided on both sides (in the propagation direction of the Rayleigh wave) of the input part IDT1, and both sides of the output part IDT3 of the mode-coupled SAW filter for Rayleigh waves. A reflector 4 provided in the (Rayleigh wave propagation direction), and an SH wave IDT 5 provided between the IDTs 1 and 3 are provided.
【０００７】入力部ＩＤＴ１と出力部ＩＤＴ３は、ＳＨ
波の方向がレイリー波に対し直角方向のため、それぞれ
のレイリー波の方向とは直角方向に配置され、ＩＤＴ
１，３の間に設けられるＳＨ波用ＩＤＴ５の電極間隔
は、ＳＨ波の伝搬速度がレイリー波の１．６倍であるた
め、１．６倍ピッチであって、ＩＤＴ１と３を接続す
る。このフィルタに適用される信号は入力部に加えら
れ、ろ波された信号は出力部から得られる。ＳＨ波用Ｉ
ＤＴ５の電極にはタップが設けられ、これを選択して接
地することによって伝搬する波のエネルギーを変えて、
ＩＤＴ１と３の間の結合度が調整できる。ＩＤＴ１と３
の間の結合度を調整すると、フィルタの特性曲線を変え
ることが可能となる。The input part IDT1 and the output part IDT3 are SH
Since the direction of the wave is perpendicular to the Rayleigh wave, the direction of each Rayleigh wave is perpendicular to the direction of the Rayleigh wave.
The electrode spacing of the SH wave IDT 5 provided between 1 and 3 is 1.6 times the pitch of the Rayleigh wave because the propagation speed of the SH wave is 1.6 times, and the IDTs 1 and 3 are connected. The signal applied to this filter is applied to the input and the filtered signal is available at the output. SH wave I
The electrode of DT5 is provided with a tap, which is selected and grounded to change the energy of the propagating wave,
The degree of coupling between IDTs 1 and 3 can be adjusted. IDT1 and 3
By adjusting the degree of coupling between, the characteristic curve of the filter can be changed.
【０００８】従来形のＳＡＷフィルタの構成では、一
度、圧電基板上に形成した２つのＩＤＴ１，３の間隔を
拡縮することは不可能であったため、結合度の調整が困
難であった。本実施例におけるＩＤＴ５の電極の接地の
選択は圧電基板上にＩＤＴ間隔を形成後に行うことがで
きる。In the configuration of the conventional SAW filter, it is impossible to increase or decrease the interval between the two IDTs 1 and 3 formed on the piezoelectric substrate once, so that it is difficult to adjust the degree of coupling. The selection of the ground of the electrode of the IDT 5 in this embodiment can be performed after the IDT interval is formed on the piezoelectric substrate.
【０００９】[0009]
【発明の効果】本発明によれば、レイリー波用の入力部
ＩＤＴと出力部ＩＤＴの間にＳＨ波用ＩＤＴを設け、Ｓ
Ｈ波用ＩＤＴに設けたタップの接地を選択的に行うこと
によって、等価的に入力部ＩＤＴと出力部ＩＤＴの間の
距離を変更できるようにし、その結果、基板上にＩＤＴ
を形成後も、結合度の調整を容易に行うことができ、所
望のフィルタ特性を得ることができる。According to the present invention, an SHT IDT is provided between an input part IDT for a Rayleigh wave and an output part IDT.
By selectively performing the grounding of the tap provided on the H-wave IDT, the distance between the input unit IDT and the output unit IDT can be equivalently changed.
After the formation, the degree of coupling can be easily adjusted, and desired filter characteristics can be obtained.
【図１】本発明の一実施例としてのモード結合形ＳＡＷ
フィルタの構成を示す図である。FIG. 1 shows a mode-coupled SAW according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a configuration of a filter.
【図２】従来例のモード結合形ＳＡＷフィルタの構成を
示す図である。FIG. 2 is a diagram illustrating a configuration of a conventional mode-coupling type SAW filter.
１…入力部ＩＤＴ ２…反射器 ３…出力部ＩＤＴ ４…反射器 ５…ＳＨ波用ＩＤＴ DESCRIPTION OF SYMBOLS 1 ... Input part IDT 2 ... Reflector 3 ... Output part IDT 4 ... Reflector 5 ... SH wave IDT
Claims (2)
タの入出力部のＩＤＴ（１，３）間にＳＨ波用ＩＤＴ
（５）を設け、機械的に結合したことを特徴とするモー
ド結合形ＳＡＷフィルタ。1. An SHT IDT between input and output IDTs (1, 3) of a mode-coupled SAW filter for a Rayleigh wave.
(5) A mode-coupled SAW filter characterized by being mechanically coupled.
分割し、該タップを選択して接地し、結合度調整を可能
にしたことを特徴とする請求項１のモード結合形ＳＡＷ
フィルタ。2. The mode-coupled SAW according to claim 1, wherein said SH wave IDT (5) is divided into multiple taps, said taps are selected and grounded, and coupling degree can be adjusted.
filter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22271792A JP3202071B2 (en) | 1992-08-21 | 1992-08-21 | Mode-coupled SAW filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22271792A JP3202071B2 (en) | 1992-08-21 | 1992-08-21 | Mode-coupled SAW filter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0669751A JPH0669751A (en) | 1994-03-11 |
| JP3202071B2 true JP3202071B2 (en) | 2001-08-27 |
Family
ID=16786808
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22271792A Expired - Fee Related JP3202071B2 (en) | 1992-08-21 | 1992-08-21 | Mode-coupled SAW filter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3202071B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1548702A1 (en) * | 2003-12-24 | 2005-06-29 | Interuniversitair Microelektronica Centrum Vzw | Method for ultra-fast controlling of a magnetic cell and related devices |
-
1992
- 1992-08-21 JP JP22271792A patent/JP3202071B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0669751A (en) | 1994-03-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20010515 |
|
| LAPS | Cancellation because of no payment of annual fees |