JP3142923B2 - Reflection bank type one-way SAW device - Google Patents
Reflection bank type one-way SAW deviceInfo
- Publication number
- JP3142923B2 JP3142923B2 JP03304202A JP30420291A JP3142923B2 JP 3142923 B2 JP3142923 B2 JP 3142923B2 JP 03304202 A JP03304202 A JP 03304202A JP 30420291 A JP30420291 A JP 30420291A JP 3142923 B2 JP3142923 B2 JP 3142923B2
- Authority
- JP
- Japan
- Prior art keywords
- idt
- saw device
- electrode
- bank type
- reflection
- 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】本発明は電極形成が容易な、所謂
反射バンク型一方向性ＳＡＷデバイスに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called reflection bank type unidirectional SAW device in which electrodes can be easily formed.
【０００２】[0002]
【従来技術】ダブル電極としたＩＤＴの組の間に反射器
を複数本備え、その反射器相互の間隔をＩＤＴと同様に
すると共に、反射器全体の配置を左右何れかのＩＤＴの
側にλ／８ずらすことによって、ＩＤＴが励起したＳＡ
Ｗに一方向性を与えた、所謂反射バンク型一方向性ＳＡ
Ｗデバイスが存在する。このデバイスの一方向性はその
他の一方向性デバイス、例えば三相一方向性又はグルー
プ型一方向性のそれ等と同等であるが、構成が通常のＳ
ＡＷフィルタと同様に一回の蒸着とフォトエッチング加
工で電極形成ができ、又外部に移相器を使用しないため
簡単であるという特色を有する。更に、ＩＤＴをダブル
電極とすることによって、このＩＤＴが通常のシングル
電極ＩＤＴの場合に発生する音響的三回反射波（ＴＴ
Ｅ）によるフィルタの通過帯域内リップルを除去するこ
とができる。この効果はこのタイプの一方向性ＩＤＴを
二個相対面させたフィルタに於いても、双方向性ＩＤＴ
の両側にこのタイプの一方向性ＩＤＴを配置したタイプ
のフィルタに於いても同様である。2. Description of the Related Art A plurality of reflectors are provided between a pair of IDTs each of which is a double electrode, the distance between the reflectors is set to be the same as that of the IDT, and the entire reflector is arranged on either the left or right IDT side by λ. / 8, the SA excited by the IDT
A so-called reflection-bank-type unidirectional SA that gives unidirectionality to W
There are W devices. The unidirectionality of this device is equivalent to that of other unidirectional devices, for example, three-phase unidirectional or group-type unidirectional, but the configuration is normal S
As in the case of the AW filter, the electrode can be formed by a single deposition and photo-etching process, and is simple because no external phase shifter is used. Furthermore, by making the IDT a double electrode, an acoustic triple reflection wave (TT) generated when the IDT is a normal single electrode IDT is used.
The ripple in the pass band of the filter according to E) can be removed. This effect is obtained even in a filter in which two unidirectional IDTs of this type are opposed to each other.
The same applies to a filter of the type in which this type of unidirectional IDT is arranged on both sides of the filter.
【０００３】しかしながら、上述したような正負ＩＤＴ
にダブル電極を用いた反射バンク型一方向性ＩＤＴに於
いては電極構成上、反射器とこれに隣接するダブル電極
の一方との間隔がλ／１６（λは正負電極が励起するＳ
ＡＷの波長）となり、周波数が高くなると製造困難或い
は製造不能となる欠点があった。However, the positive and negative IDTs described above
In a reflection bank type unidirectional IDT using double electrodes, the interval between the reflector and one of the double electrodes adjacent to the reflector is λ / 16 (where λ is S which is excited by the positive and negative electrodes).
AW wavelength), and when the frequency becomes high, there is a drawback that manufacturing becomes difficult or impossible.
【０００４】[0004]
【発明の目的】本発明は上述した如き従来の反射バンク
型一方向性ＳＡＷデバイスに於いて、反射器とこれに隣
接するダブル電極の一方との間隔が狭くなるために製造
が困難となるという欠点を解決するためになされたもの
であって、高周波領域での電極形成が容易な反射バンク
型一方向性ＳＡＷデバイスを提供することを目的とす
る。SUMMARY OF THE INVENTION It is an object of the present invention to provide a conventional reflection bank type unidirectional SAW device as described above, in which the distance between the reflector and one of the adjacent double electrodes is reduced, which makes the fabrication difficult. An object of the present invention is to provide a reflection bank type one-way SAW device which has been made in order to solve the drawback and is easy to form an electrode in a high frequency region.
【０００５】[0005]
【発明の概要】上述の目的を達成するため、本発明に於
いては反射器に隣接するダブル電極の一方を除去したも
のである。SUMMARY OF THE INVENTION To achieve the above object, the present invention eliminates one of the double electrodes adjacent to the reflector.
【０００６】[0006]
【実施例】以下、本発明を図面に示した実施例に基づい
て詳細に説明する。実施例の説明に先立って、本発明の
理解を助けるため、従来の反射バンク型一方向性ＳＡＷ
デバイスの電極構成について簡単に説明する。図２は反
射バンク型一方向性ＳＡＷデバイスの基本的電極構成を
示す図であって、所謂正規型のＩＤＴ配列区間（三本の
ＩＤＴ１、２、３を一セットとする）の間にλ／２間隔
の複数の反射器４1 、４2 、…、４n を挿入し、この反
射器４1 、４2 、…、４n の組を全体としてλ／８だけ
左右何れかの正規型ＩＤＴに寄せたものである。この結
果、前記ＩＤＴ３（必ずアース電極である。）と反射器
４1 とのエッジ間隔がλ／８となることは言うまでもな
い。しかしながら、このタイプのデバイスはこれをフィ
ルタに用いた場合、通過帯域にリップルが発生するた
め、図３に示すようにＩＤＴ１、２、３を夫々ダブル電
極１1 乃至３2 としリップルを抑圧することが行われて
いる。しかしながら、このような電極構成をとると反射
器４1 とアース電極であるダブル電極の一方３2 とのエ
ッジ間隔はλ／１６となり、高周波領域に於いては製造
不能となること前述の通りである。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. Prior to the description of the embodiments, in order to assist understanding of the present invention, a conventional reflection bank type one-way SAW will be described.
The electrode configuration of the device will be briefly described. FIG. 2 is a diagram showing a basic electrode configuration of a reflection bank type one-way SAW device. In a so-called normal type IDT array section (three IDTs 1, 2, and 3 are set as one set), λ / a plurality of reflectors 4 1, 2 interval 4 2, ..., 4 n insert the this reflector 4 1, 4 2, ..., 4 n set as a whole by lambda / 8 to the left or right of the normal type IDT of It is sent to. As a result, the IDT 3 (which is always ground electrode.) And the reflector 4 it is needless to say that the first edge interval between is lambda / 8. However, if this type of device is used as a filter, ripples will occur in the pass band. Therefore, as shown in FIG. 3, the IDTs 1, 2, and 3 should be double electrodes 11 to 3 2 to suppress ripples. Has been done. However, such edge interval between the taking electrode structure and the reflector 4 1 and one 3 2 double electrode is an earth electrode lambda / 16, and the is at the high frequency region as described above to become impossible production is there.
【０００７】この問題を解決するため、本発明の反射バ
ンク型ＳＡＷデバイスは反射器４1と隣接するダブル電
極３2 を除去したものである。ここで、ダブル電極２
1 、２2 を正電極とし、１1 、３1 を負電極とするか
ら、正電極２1 の左及び正電極２2 の右には夫々負電極
１2 及び３1 が存在するためＳＡＷを励起する効率は低
下しないと考えて良い。これを実験によって確認するた
め、上述のデバイス二個を夫々の励起するＳＡＷが強調
される方向を相対面させたフィルタを試作し、その特性
を調べたところ図４に示すような結果を得た。これはデ
ジタル自動車電話用ＩＦフィルタのスペックを満足する
ものであって、上述した電極構成法の正当性が実証され
た。[0007] To solve this problem, the reflection bank type SAW device of the present invention has been removed double electrode 3 2 adjacent to the reflector 4 1. Here, double electrode 2
1, 2 2 and the positive electrode, 1 1, 3 1 from the negative electrode, the SAW for positive electrodes 2 1 of the left and the positive electrode 2 2 of each negative electrode 1 2 and 3 1 to the right is present It can be considered that the efficiency of excitation does not decrease. In order to confirm this by an experiment, a filter was fabricated in which the two devices described above were made to face each other in a direction in which the SAW for exciting each was excited, and the characteristics were examined. As a result, the results shown in FIG. 4 were obtained. . This satisfies the specifications of the digital car telephone IF filter, and the validity of the above-described electrode configuration method has been proved.
【０００８】[0008]
【発明の効果】本発明の反射バンク型一方向性ＳＡＷデ
バイスは以上説明したように構成するものであるから、
従来一般の正負ＩＤＴをダブル電極としたものと同等の
特性を有し、しかも電極の形成が容易であるゆえ、高周
波化の著しい昨今の通信機器用各種フィルタに適用する
上で極めて効果的である。The reflection bank type one-way SAW device of the present invention is constructed as described above.
It has the same characteristics as a conventional general positive / negative IDT having a double electrode, and is easy to form. Therefore, it is extremely effective when applied to various filters for communication equipment in recent years where the frequency is significantly increased. .
【０００９】[0009]
【図１】本発明の反射バンク型一方向性ＳＡＷデバイス
の電極構成を示す平面図。FIG. 1 is a plan view showing an electrode configuration of a reflection bank type unidirectional SAW device of the present invention.
【図２】従来の反射バンク型一方向性ＳＡＷデバイスの
基本的な電極構成を示す平面図。FIG. 2 is a plan view showing a basic electrode configuration of a conventional reflection bank type unidirectional SAW device.
【図３】従来の反射バンク型一方向性ＳＡＷデバイスの
他の電極構成を示す平面図。FIG. 3 is a plan view showing another electrode configuration of a conventional reflection bank type unidirectional SAW device.
【図４】本発明の反射バンク型一方向性ＳＡＷデバイス
を用いて構成したフィルタの特性を示す実験結果の図。FIG. 4 is a view of an experimental result showing characteristics of a filter configured using the reflection bank type unidirectional SAW device of the present invention.
１1 乃至３2 ダブル電極としたＩＤＴ ４1 乃至４3 反射器1 1 3 2 Double electrode was IDT 4 1 to 4 3 reflector
フロントページの続き (56)参考文献 特開 平４−309005（ＪＰ，Ａ) 特開 昭60−123123（ＪＰ，Ａ) 米国特許4642506（ＵＳ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) H03H 9/145 Continuation of front page (56) References JP-A-4-309005 (JP, A) JP-A-60-123123 (JP, A) U.S. Pat. No. 4,642,506 (US, A) (58) Fields investigated (Int. 7 , DB name) H03H 9/145
Claims (1)
器を複数本備えその反射器相互の間隔をＩＤＴと同様に
すると共に、反射器全体の配置を左右何れかのＩＤＴの
側にλ／８ずらすことによってＩＤＴが励起したＳＡＷ
に一方向性を与えたＳＡＷデバイスに於いて、反射器に
隣接するダブル電極の一方を除去したことを特徴とする
反射バンク型一方向性ＳＡＷデバイス。A plurality of reflectors are provided between a pair of IDTs each having a double electrode, the distance between the reflectors is made the same as that of the IDT, and the overall arrangement of the reflectors is set to λ on either the left or right IDT side. SAW excited by IDT by shifting by / 8
2. A reflection bank type unidirectional SAW device according to claim 1, wherein one of the double electrodes adjacent to the reflector is removed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03304202A JP3142923B2 (en) | 1991-10-23 | 1991-10-23 | Reflection bank type one-way SAW device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03304202A JP3142923B2 (en) | 1991-10-23 | 1991-10-23 | Reflection bank type one-way SAW device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05121991A JPH05121991A (en) | 1993-05-18 |
| JP3142923B2 true JP3142923B2 (en) | 2001-03-07 |
Family
ID=17930248
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03304202A Expired - Fee Related JP3142923B2 (en) | 1991-10-23 | 1991-10-23 | Reflection bank type one-way SAW device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3142923B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5521565A (en) * | 1988-09-28 | 1996-05-28 | Siemens Aktiengesellschaft | Surface wave interdigital transducer and surface wave filter with symmetric or predeterminable asymmetric transfer characteristic between input and output |
-
1991
- 1991-10-23 JP JP03304202A patent/JP3142923B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05121991A (en) | 1993-05-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |