JPH0487410A - Surface wave device - Google Patents
Surface wave deviceInfo
- Publication number
- JPH0487410A JPH0487410A JP20288190A JP20288190A JPH0487410A JP H0487410 A JPH0487410 A JP H0487410A JP 20288190 A JP20288190 A JP 20288190A JP 20288190 A JP20288190 A JP 20288190A JP H0487410 A JPH0487410 A JP H0487410A
- Authority
- JP
- Japan
- Prior art keywords
- wave device
- piezoelectric substrate
- waves
- resonance
- face
- 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.)
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Links
- 239000000758 substrate Substances 0.000 claims abstract description 25
- 238000006073 displacement reaction Methods 0.000 claims description 5
- 230000001902 propagating effect Effects 0.000 claims description 2
- 238000010897 surface acoustic wave method Methods 0.000 description 16
- 239000000919 ceramic Substances 0.000 description 4
- 230000005684 electric field Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 244000126211 Hericium coralloides Species 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- -1 for example Substances 0.000 description 1
- HFGPZNIAWCZYJU-UHFFFAOYSA-N lead zirconate titanate Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ti+4].[Zr+4].[Pb+2] HFGPZNIAWCZYJU-UHFFFAOYSA-N 0.000 description 1
- 229910052451 lead zirconate titanate Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
Landscapes
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、ＢＯ３波等のように変位が表面波伝播方向と
垂直な方向の変位を主体とするＳＨタイプの表面波を利
用した表面波装置に関する。[Detailed Description of the Invention] [Field of Industrial Application] The present invention is directed to surface waves that utilize SH type surface waves, such as BO3 waves, whose displacement is mainly perpendicular to the surface wave propagation direction. Regarding equipment.
圧電基板を伝播する表面波のうち、変位が伝播方向と垂
直な方向の変位を主体とするＳＨタイプの表面波には、
ＢＯ３波やラブ波等がある。Among the surface waves propagating through a piezoelectric substrate, SH type surface waves whose displacement is mainly perpendicular to the propagation direction include:
There are BO3 waves, love waves, etc.
ＢＯ３波は、圧電セラミックス等の材料を用いて、例え
ば第２図に示す表面波装置を構成した場合に励振される
。第２図において、１は圧電基板を示し、例えばＰｂ
（Ｔｊ、Ｚｒ）Ｏｓ系圧電セラミックスにより構成され
ている。圧電基板１の表面には、くし歯電極２．３が形
成されている。The BO3 wave is excited when, for example, a surface acoustic wave device shown in FIG. 2 is constructed using a material such as piezoelectric ceramics. In FIG. 2, 1 indicates a piezoelectric substrate, for example, Pb
It is composed of (Tj, Zr)Os-based piezoelectric ceramics. A comb-shaped electrode 2.3 is formed on the surface of the piezoelectric substrate 1.
くし歯電極２．３は、互いに間挿し合う複数の電極指２
ａ、３ａを有する。なお、２ｂ、３ｂは、それぞれ、バ
スバーを示す。また、矢印Ｐば圧電基板１の分極軸を示
す。The comb-tooth electrode 2.3 has a plurality of electrode fingers 2 inserted between each other.
a, 3a. Note that 2b and 3b each indicate a bus bar. Further, arrow P indicates the polarization axis of the piezoelectric substrate 1.
第２図の表面波装置４において、くし歯電極２゜３から
交流電界を印加すると、゛表面波伝播方向Ａと垂直な方
向の変位のみ、すなわち横波成分しか有さないＢＯ３波
が励振される。In the surface wave device 4 shown in FIG. 2, when an alternating current electric field is applied from the comb-teeth electrodes 2.3, a BO3 wave having only displacement in the direction perpendicular to the surface wave propagation direction A, that is, only a transverse wave component, is excited. .
ＢＧＳ波を利用した表面波装置４では、ＢＧＳ波は、圧
電基板１の両端面１ａ、ｌｂで完全に反射される。従っ
て、表面波装置４では、くし歯電極２．３の側方に反射
器を構成する必要がないため、チップサイズを従来のレ
イリー波を利用した表面波装置に比べて大幅に小型化す
ることができ、かつ両端面の精度を高めることにより、
より高周波域で使用し得るデバイスを提供することがで
きるという、大きな利点を有する。In the surface acoustic wave device 4 using BGS waves, the BGS waves are completely reflected by both end surfaces 1a and lb of the piezoelectric substrate 1. Therefore, in the surface wave device 4, there is no need to configure a reflector on the side of the comb-teeth electrode 2.3, so the chip size can be significantly reduced compared to the conventional surface wave device using Rayleigh waves. By increasing the accuracy of both end faces,
This has the great advantage of being able to provide a device that can be used in a higher frequency range.
（発明が解決しようとする課題〕
しかしながら、表面波装置４では、実際には、両端面１
３１ｂの精度を高めても、第３図に示すように、インピ
ーダンス−周波数特性上番こ不要スプリアスＢが生しる
という問題があった。(Problem to be Solved by the Invention) However, in the surface wave device 4, in reality, both end surfaces 1
Even if the precision of 31b is improved, there is a problem in that an unnecessary spurious B occurs in the impedance-frequency characteristic as shown in FIG.
この不要スプリアスＢは、交流電界が印加された際にバ
スパー２ｂ、３ｂ間で励振されるバルク波の共振に基づ
くものと考えられる。バルク波の基本周波数ｆは、バル
ク波の音速をＶとした場合に、ｆ＝ｖ／２Ｌ（但し、Ｌ
は側面１ｃ、１６間の距ＩＩＩ）で表される。すなわち
、この基本周波数ｆの奇数倍の周波数域において、バル
ク波共振に基づく不要スプリアスが発生していた。This unnecessary spurious B is considered to be based on the resonance of the bulk wave excited between the buspars 2b and 3b when an alternating current electric field is applied. The fundamental frequency f of the bulk wave is f=v/2L (however, L
is represented by the distance III) between the side surfaces 1c and 16. In other words, unnecessary spurious noise based on bulk wave resonance occurs in a frequency range that is an odd multiple of the fundamental frequency f.
よって、本発明の目的は、上記のようなバルク波に基づ
く不要スプリアスを効果的に抑圧し得る構造を備えた、
ＳＨタイプの表面波を利用した表面波装置を提供するこ
とにある。Therefore, an object of the present invention is to provide a structure that can effectively suppress unnecessary spurious waves based on bulk waves as described above.
An object of the present invention is to provide a surface wave device using SH type surface waves.
本発明の表面波装置は、圧！基板を伝播する表面波のう
ち、変位が表面波伝播方向と垂直な方向の変位を主体と
するＳＨタイプの表面波、すなわちＢＧＳ波やラブ波を
利用したものであり、下記の構成を備えることを特徴と
する。The surface wave device of the present invention has pressure! Of the surface waves that propagate through the substrate, it utilizes SH type surface waves whose displacement is mainly perpendicular to the surface wave propagation direction, that is, BGS waves and Love waves, and must have the following configuration. It is characterized by
圧電基板と、この圧電基板の両端面間でＳＨタイプの表
面波を反射させるように、該圧電基板の表面に形成され
ており、互いに間挿し合う複数の電極指を有する少なく
とも一対のくし歯電極とを備え、圧電基板の上記両端面
を結ぶ一対の側面の少なくとも一方の側面が、電極指の
延びる方向に垂直な面から傾斜されていることを特徴と
する。a piezoelectric substrate; and at least a pair of comb-shaped electrodes formed on the surface of the piezoelectric substrate so as to reflect SH type surface waves between both end faces of the piezoelectric substrate, and having a plurality of interdigitated electrode fingers. and at least one side surface of a pair of side surfaces connecting the above-mentioned both end surfaces of the piezoelectric substrate is inclined from a plane perpendicular to the direction in which the electrode fingers extend.
バルク波は、ＳＨタイプの表面波の反射される両端面間
を結ぶ一対の側面間において励振される。The bulk wave is excited between a pair of side surfaces connecting both end surfaces on which the SH type surface wave is reflected.
しかしながら、本発明では、この一対の側面の少なくと
も一方が、電極指の延びる方向に垂直な面から傾斜され
ているため、該一対の側面間にバルク波が定在波として
立ち難くされている。すなわち、上記傾斜されている側
面において反射されるバルク波が他方の側面方向に直進
しないため、バルク波に基づく共振現象が効果的に抑制
される。However, in the present invention, since at least one of the pair of side surfaces is inclined from a plane perpendicular to the direction in which the electrode finger extends, it is difficult for bulk waves to form as standing waves between the pair of side surfaces. That is, since the bulk waves reflected on the inclined side surface do not go straight toward the other side surface, the resonance phenomenon based on the bulk waves is effectively suppressed.
よって、バルク波共振に基づく不要スプリアスの発生を
効果的に抑制することが可能とされている。Therefore, it is possible to effectively suppress the generation of unnecessary spurious waves based on bulk wave resonance.
以下、本発明の一実施例につき説明する。 An embodiment of the present invention will be described below.
第１図において、圧電基板１１の表面にくし歯電極１２
．１３を形成することにより表面波装置１４が形成され
ている。In FIG. 1, a comb-shaped electrode 12 is provided on the surface of a piezoelectric substrate 11
．． By forming 13, a surface acoustic wave device 14 is formed.
圧電基板１１は、Ｐｂ （Ｔｉ、Ｚｒ）０．のような圧
電セラミックスよりなり、両端面１１ａ。The piezoelectric substrate 11 is made of Pb (Ti, Zr)0. Both end surfaces 11a are made of piezoelectric ceramics such as.
１１ｂ間でＢＧＳ波を反射させるために、上記のような
くし歯電極１２．１３を有する。（し歯電極１２，１３
は、互いに間挿し合う複数の電極指１２ａ、１３ａをそ
れぞれ有し、各電極指１２ａ１３ａは、バスパー１２ｂ
、１３ｂにより連結されている。In order to reflect the BGS waves between the electrodes 11b, the interdigitated electrodes 12 and 13 as described above are provided. (The toothed electrodes 12, 13
has a plurality of electrode fingers 12a and 13a that are inserted into each other, and each electrode finger 12a13a is connected to a busper 12b.
, 13b.
すなわち、本実施例の表面波装置１４は、第２図に示し
た従来の表面波装置４と同様の電極構造を有する。従っ
て、くし歯電極１２．１３間に交流電界を印加すれば、
矢印入方向にＢＧＳ波が伝播され、かつ両端面１１ａ、
ｌｌｂ間で該ＢＧＳ波が反射されて共振する。That is, the surface acoustic wave device 14 of this embodiment has the same electrode structure as the conventional surface acoustic wave device 4 shown in FIG. Therefore, if an alternating current electric field is applied between the comb-teeth electrodes 12 and 13,
BGS waves are propagated in the direction of the arrow, and both end surfaces 11a,
The BGS wave is reflected and resonates between llb.
本実施例の特徴は、圧電基板１１の平面形状にある。す
なわち、圧電基板１１の一対の側面１１Ｃ，１１ｄのう
ち、一方の側面１１ｃが、端面１１ａ側から端面１１ｂ
側に至るに連れて、バスパー１３ｂから遠ざかるように
形成されている。すなわち、バスパー１３ｂの外側に、
突出部ｌｉｅが形成されており、それによって一対の側
面１１Ｃが電極指１２ａ、１３ａの延びる方向に垂直な
面から傾斜されている。The feature of this embodiment lies in the planar shape of the piezoelectric substrate 11. That is, among the pair of side surfaces 11C and 11d of the piezoelectric substrate 11, one side surface 11c moves from the end surface 11a side to the end surface 11b.
It is formed so as to move away from the bus spar 13b as it approaches the side. That is, on the outside of the bus spar 13b,
A protrusion lie is formed so that the pair of side surfaces 11C are inclined from a plane perpendicular to the direction in which the electrode fingers 12a, 13a extend.
よって、本実施例の表面波装置１４では、バスバー１２
ｂ、１３ｂ間で励振されたノ＼ルク波は、側面１１ｃで
反射された場合、他方の側面ｌｉｄ側に直進せず、端面
１１ｂ側に散乱される。そのため、側面１１ｃ、ｌｉｄ
間にバルク波の定在波が立ち難く、それによってバルク
波の共振が抑制されている。Therefore, in the surface acoustic wave device 14 of this embodiment, the bus bar 12
When the Norck wave excited between b and 13b is reflected by the side surface 11c, it does not go straight to the other side surface lid, but is scattered toward the end surface 11b. Therefore, the side 11c, lid
It is difficult for standing waves of bulk waves to stand between them, thereby suppressing the resonance of bulk waves.
第１図に示した表面波装置１４のインピーダンス−周波
数特性を第４図に示す。この特性は、圧′ｇ１基板１１
として、かつ第１図の寸法Ｘ、Ｙ、Ｚ及厚みが、それぞ
れ、８８０μｍ、５５０μｍ及び７００μｍのチタン酸
ジルコン酸鉛系セラミックスよりなる圧電基板上に１０
対のくし歯電極１２１３を形成した表面波装置とについ
てのものである。FIG. 4 shows the impedance-frequency characteristics of the surface acoustic wave device 14 shown in FIG. 1. This characteristic is based on the pressure 'g1 substrate 11
10 on a piezoelectric substrate made of lead zirconate titanate ceramics with dimensions X, Y, Z and thickness of 880 μm, 550 μm and 700 μm in FIG.
This is about a surface wave device in which a pair of comb-shaped electrodes 1213 are formed.
第４図及び第３図を比較すれば明らかなように、本実施
例の表面波装置１４では、***振周波数よりも高周波域
側における不要スプリアスが大幅に低減されていること
、並びに共振抵抗と***振抵抗との比も大幅に高められ
ていることがわかる。As is clear from a comparison of FIG. 4 and FIG. 3, in the surface acoustic wave device 14 of this embodiment, unnecessary spurious in the higher frequency range than the anti-resonance frequency is significantly reduced, and the resonance resistance and It can be seen that the ratio to anti-resonance resistance is also significantly increased.
すなわち、バルク波の共振に基づく不要スプリアスがほ
とんど発生していない、インピーダンス−周波数特性が
実現されることがわかる。That is, it can be seen that an impedance-frequency characteristic in which almost no unnecessary spurious noise based on bulk wave resonance is generated is achieved.
上記実施例では、突出部ｌｉｅを有する圧電基板１１を
用いて、一方の側面１１ｃをバスバー１３ｂに対して交
差するように配置することにより、側面１１ｃを電極指
１２ａ、１３ａの延びる方向に垂直な面から傾斜されて
いた。しかしながら、本発明は、このような形状のもの
に限定されない。In the above embodiment, the piezoelectric substrate 11 having the protruding portion lie is arranged so that one side surface 11c crosses the bus bar 13b, so that the side surface 11c is perpendicular to the direction in which the electrode fingers 12a and 13a extend. It was tilted away from the surface. However, the present invention is not limited to such a shape.
すなわち、第５図に平面図で示すように、一対の側面１
１ｃ、ｌｉｄの何れもがバスバー１２ｂ。That is, as shown in the plan view in FIG.
1c and lid are both bus bars 12b.
１３ｂに対して交差する方向に延びるように配置し、そ
れによって双方の側面１１ｃ、ｌｉｄを電極指の延びる
方向に対して垂直な面から傾斜させてもよい。It may be arranged so as to extend in a direction crossing the electrode fingers 13b, thereby making both side surfaces 11c and lid inclined from a plane perpendicular to the direction in which the electrode fingers extend.
同様に、第６図に示すように、曲面状の側面１１ｃ
ｌｉｄを設けることにより、各側面１１Ｃ１ｌｉｄを、
電極指１２ａ、１３ａの延びる方向に対して垂直な面か
ら傾斜させてもよい。Similarly, as shown in FIG. 6, the curved side surface 11c
By providing a lid, each side 11C1lid,
The electrode fingers 12a, 13a may be inclined from a plane perpendicular to the direction in which they extend.
さらに、第７図に電極指の延びる方向に沿う断面図で示
すように、一対の側面１１ｃ、ｌｌｄの双方を厚み方向
に傾斜させ、それによって一対の側面１１ｃ、１１ｄを
電極指１２ａ、１３ａの延びる方向に垂直な面から傾斜
させてもよい。Furthermore, as shown in a cross-sectional view along the extending direction of the electrode fingers in FIG. It may be inclined from a plane perpendicular to the extending direction.
上記実施例ではＢＧＳ波を利用した表面波装置につき説
明したが、ラブ波のような他の形式のＳＨタイプの表面
波を利用した表面波装置にも本発明を適用することがで
きる。Although the above embodiment describes a surface acoustic wave device using BGS waves, the present invention can also be applied to a surface acoustic wave device using other types of SH type surface waves such as Love waves.
本発明によれば、ＳＨタイプの表面波が反射される両端
面を結ぶ一対の側面の少なくとも一方が、電極指の延び
る方向に対して垂直な面から傾斜されているため、該一
対の側面間に発生するノ１ルク波の共振を効果的に抑制
することができ、それによってインピーダンス−周波数
特性上に現れるバルク波の共振に基づ（不要スプリアス
を効果的に抑制することができる。従って、インピーダ
ンス周波数特性の優れた表面波装置を提供することが可
能となる。According to the present invention, since at least one of the pair of side surfaces connecting the end surfaces on which SH type surface waves are reflected is inclined from a plane perpendicular to the direction in which the electrode fingers extend, the distance between the pair of side surfaces is Based on the bulk wave resonance that appears on the impedance-frequency characteristic (unnecessary spurious) can be effectively suppressed. It becomes possible to provide a surface acoustic wave device with excellent impedance frequency characteristics.
第１図は本発明の一実施例にかかる表面波装置の斜視図
、第２図は従来の表面波装置の斜視図、第３図は従来の
表面波装置のインピーダンス−周波数特性を示す図、第
４図は第一図実施例の表面波装置のインピーダンス−周
波数特性を示す図、第５図は本発明の他の実施例の表面
波装置の平面図、第６図は本発明のさらに他の実施例の
表面波装置の平面図、第７図は本発明の他の実施例の表
面波装置の断面図である。
図において、１１は圧！基板、１１ａ、１１ｂは端面、
ｌｌｃ、ｌｌｄは側面、１２．１３はくし歯電極、１２
ａ、１３ａは電極指、１４は表面波装置、ＡはＢＧＳ波
の伝播方向を示す。FIG. 1 is a perspective view of a surface wave device according to an embodiment of the present invention, FIG. 2 is a perspective view of a conventional surface wave device, and FIG. 3 is a diagram showing impedance-frequency characteristics of a conventional surface wave device. FIG. 4 is a diagram showing the impedance-frequency characteristics of the surface acoustic wave device of the embodiment shown in FIG. 1, FIG. 5 is a plan view of the surface acoustic wave device of another embodiment of the present invention, and FIG. FIG. 7 is a plan view of a surface acoustic wave device according to an embodiment of the present invention, and FIG. 7 is a sectional view of a surface acoustic wave device according to another embodiment of the present invention. In the figure, 11 is pressure! The substrate, 11a and 11b are end surfaces,
llc, lld are side surfaces, 12.13 are comb-shaped electrodes, 12
a and 13a are electrode fingers, 14 is a surface acoustic wave device, and A is the propagation direction of the BGS wave.
Claims (1)
伝播方向と垂直な方向の変位を主体とするＳＨタイプの
表面波を利用した表面波装置であって、 圧電基盤と、 前記圧電基盤の両端面間で表面波を反射させるように、
該圧電基板の表面に形成されており、かつ互いに間挿し
合う複数本の電極指を有する、少なくとも一対のくし歯
電極とを備え、 圧電基板の前記両端面を結ぶ一対の側面の内、少なくと
も一方の側面が電極指の延びる方向と垂直な面から傾斜
されていることを特徴とする、表面波装置。(1) A surface wave device that utilizes an SH type surface wave in which the displacement is mainly in a direction perpendicular to the surface wave propagation direction among surface waves propagating through a piezoelectric substrate, the piezoelectric substrate and the piezoelectric In order to reflect surface waves between both end faces of the base,
at least one pair of comb-shaped electrodes formed on the surface of the piezoelectric substrate and having a plurality of interdigitated electrode fingers; at least one of the pair of side surfaces connecting the end surfaces of the piezoelectric substrate; A surface wave device characterized in that the side surface of the surface wave device is inclined from a plane perpendicular to the direction in which the electrode fingers extend.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20288190A JPH0487410A (en) | 1990-07-30 | 1990-07-30 | Surface wave device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20288190A JPH0487410A (en) | 1990-07-30 | 1990-07-30 | Surface wave device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0487410A true JPH0487410A (en) | 1992-03-19 |
Family
ID=16464751
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20288190A Pending JPH0487410A (en) | 1990-07-30 | 1990-07-30 | Surface wave device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0487410A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5986523A (en) * | 1997-08-29 | 1999-11-16 | Murata Manufacturing Co., Ltd. | Edge reflection type longitudinally coupled surface acoustic wave filter |
| US7397327B2 (en) | 2004-04-08 | 2008-07-08 | Murata Manufacturing Co., Ltd. | Surface acoustic wave filter and method of producing the same |
-
1990
- 1990-07-30 JP JP20288190A patent/JPH0487410A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5986523A (en) * | 1997-08-29 | 1999-11-16 | Murata Manufacturing Co., Ltd. | Edge reflection type longitudinally coupled surface acoustic wave filter |
| US7397327B2 (en) | 2004-04-08 | 2008-07-08 | Murata Manufacturing Co., Ltd. | Surface acoustic wave filter and method of producing the same |
| EP1734654A4 (en) * | 2004-04-08 | 2009-12-23 | Murata Manufacturing Co | Surface acoustic wave filter and manufacturing method thereof |
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