JP5312067B2 - Surface acoustic wave device and communication device - Google Patents

Surface acoustic wave device and communication device Download PDF

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JP5312067B2
JP5312067B2 JP2009018417A JP2009018417A JP5312067B2 JP 5312067 B2 JP5312067 B2 JP 5312067B2 JP 2009018417 A JP2009018417 A JP 2009018417A JP 2009018417 A JP2009018417 A JP 2009018417A JP 5312067 B2 JP5312067 B2 JP 5312067B2
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裕二 森
剛 仲井
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Kyocera Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface acoustic wave apparatus improving out-of-band attenuation near a pass band and out-of-band attenuation on a further high frequency side outside the pass band while balancing them with each other, and a communication apparatus. <P>SOLUTION: A reference-potential bus bar electrode 1a of a first IDT electrode 1 is connected through first connection wiring 30 to a first part 25 of a reference-potential electrode 12 positioned on the extension in a direction along a propagation direction and on the first IDT electrode 1 side; a reference-potential bus bar electrode 3a of a third IDT electrode 3 is connected through second connection wiring 31 to a second part 26 of the reference-potential electrode 12 on the extension in a direction perpendicular to the propagation direction; a reference-potential bus bar electrode 2a of a second IDT electrode 2 is connected through fourth connection wiring 33 to a fourth part 28 separated from the first part 25 by a predetermined distance in a direction from the second part 26 to the first part 25 along the reference-potential electrode 12; and a gap G is formed between the fourth part 28 and a fifth part 29 of the reference-potential electrode 12. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

本発明は、例えば携帯電話等の移動体通信機器に用いられる弾性表面波フィルタや弾性表面波共振器等の弾性表面波素子、弾性表面波装置及びこれを備えた通信装置に関するものである。   The present invention relates to a surface acoustic wave element, a surface acoustic wave device such as a surface acoustic wave filter and a surface acoustic wave resonator used in a mobile communication device such as a mobile phone, and a communication device including the surface acoustic wave device.

従来、携帯電話や自動車電話等の移動体通信機器のＲＦ段に用いられる周波数選択フィルタ（以下、フィルタともいう）として、弾性表面波フィルタが広く用いられている。一般に、周波数選択フィルタに求められる特性としては、広通過帯域、低損失、高減衰量等の諸特性が挙げられる。   Conventionally, a surface acoustic wave filter has been widely used as a frequency selection filter (hereinafter also referred to as a filter) used in an RF stage of a mobile communication device such as a mobile phone or a car phone. In general, characteristics required for a frequency selective filter include various characteristics such as a wide passband, low loss, and high attenuation.

また、ＧＳＭ(Global System for Mobile Communications)などのＲｘフィルタは受信周波数の信号波だけでなく、２倍波、３倍波の信号が漏れてくるために、２倍波、３倍波の周波数における帯域外減衰量を確保することが要求されている。しかし、ＰＣＳ（Personal Communication Services）など３倍波の周波数が６ＧＨｚ付近である場合、ＩＤＴ電極間での電気的な干渉が発生し易いために、減衰量を大きくすることが難しい。従って、６ＧＨｚといった高周波帯域における減衰量を大きくすることに対する要望が大きい。   In addition, Rx filters such as GSM (Global System for Mobile Communications) leak not only the signal wave of the reception frequency but also the second harmonic wave and the third harmonic wave. It is required to secure out-of-band attenuation. However, when the frequency of the third harmonic wave such as PCS (Personal Communication Services) is around 6 GHz, it is difficult to increase the attenuation amount because electric interference easily occurs between the IDT electrodes. Therefore, there is a great demand for increasing the attenuation in a high frequency band such as 6 GHz.

これらの要求特性に対して、電気信号を弾性表面波に変換させるＩＤＴ（Inter Digital Transducer）電極及び反射器電極を有する弾性表面波素子をラダー型に構成したラダー型回路を有する弾性表面波フィルタが提案されている。   In response to these required characteristics, a surface acoustic wave filter having a ladder type circuit in which a surface acoustic wave element having an IDT (Inter Digital Transducer) electrode and a reflector electrode for converting an electric signal into a surface acoustic wave is configured in a ladder type is provided. Proposed.

例えば、特許文献１には、圧電基板上に複数の弾性表面波素子によりラダー型回路を構成した弾性表面波フィルタが開示されている。並列弾性表面波素子に直列にインダクタを付加した構成とすることにより、通過帯域外に減衰極を形成し、帯域外減衰量を向上させる技術が開示されている（特許文献１を参照）。   For example, Patent Document 1 discloses a surface acoustic wave filter in which a ladder type circuit is configured by a plurality of surface acoustic wave elements on a piezoelectric substrate. A technique is disclosed in which an attenuation pole is formed outside the pass band and the amount of attenuation outside the band is improved by adopting a configuration in which an inductor is added in series to the parallel surface acoustic wave element (see Patent Document 1).

また、引用文献２には、並列腕共振子に、直列にインピーダンス素子を接続し、通過帯域外に減衰極を形成することにより、帯域外減衰量を増大させることが開示されている。   Further, cited document 2 discloses that an impedance element is connected in series to a parallel arm resonator and an attenuation pole is formed outside the pass band, thereby increasing the amount of attenuation outside the band.

また、特許文献３には、並列腕共振子に、それぞれ直列にインダクタを付加することにより、帯域外減衰量を向上させることが開示されている。   Patent Document 3 discloses that an out-of-band attenuation is improved by adding an inductor in series to each of the parallel arm resonators.

特開平５−１８３３８０号公報JP-A-5-183380 特開平１０−１６３８０８号公報JP-A-10-163808 特開２００４−７２５０号公報JP 2004-7250 A

しかしながら、従来の技術においては、減衰極を設定する位置を調整することが難しく、通過帯域近傍の帯域外減衰量と、通過帯域外のより高周波側における帯域外減衰量とを両立させて向上させることが困難であるといる問題点があった。   However, in the conventional technique, it is difficult to adjust the position where the attenuation pole is set, and both the out-of-band attenuation near the passband and the out-of-band attenuation on the higher frequency side outside the passband are improved at the same time. There was a problem that it was difficult.

従って、本発明は、上記従来の問題点に鑑みて完成されたものであり、その目的は、通過帯域近傍の帯域外減衰量と、通過帯域外のより高周波側における帯域外減衰量とを両立させて向上させることができる弾性表面波装置、及び通信装置を得ることである。   Therefore, the present invention has been completed in view of the above-described conventional problems, and the object thereof is to achieve both the out-of-band attenuation near the passband and the out-of-band attenuation on the higher frequency side outside the passband. And obtaining a surface acoustic wave device and a communication device that can be improved.

本発明の弾性表面波素子は、圧電基板と、前記圧電基板の主面に形成され、前記圧電基板の主面を伝搬する弾性表面波の伝搬方向に沿って順に配列された第１乃至第５のＩＤＴ電極と、前記圧電基板の主面に前記第１乃至第５のＩＤＴ電極を取り囲むように形成された環状の基準電位電極と、を備えた弾性表面波素子であって、前記第１〜第５のＩＤＴ電極は、それぞれ基準電位バスバー電極を有し、前記第１のＩＤＴ電極の基準電位バスバー電極は、前記伝搬方向に沿った方向の延長上で且つ前記第１のＩＤＴ電極側に位置する前記基準電位電極の第１の部位に第１の接続配線を介して接続され、前記第３のＩＤＴ電極の基準電位バスバー電極は、前記伝搬方向に直交する方向の延長上にある前記基準電位電極の第２の部位に第２の接続配線を介して接続され、前記第５のＩＤＴ電極の基準電位バスバー電極は、前記伝搬方向に沿った方向の延長上で且つ前記第５のＩＤＴ電極側に位置する前記基準電位電極の第３の部位に第３の接続配線を介して接続され、前記第２のＩＤＴ電極の基準電位バスバー電極は、前記第２の部位との間に前記第１の部位を挟んで該第１の部位と所定間隔だけ離れた前記基準電位電極上の第４の部位に第４の接続配線を介して接続され、前記第４のＩＤＴ電極の基準電位バスバー電極は、前記第２の部位との間に前記第３の部位を挟んで該第３の部位と所定間隔だけ離れた前記基準電位電極上の第５の部位に第５の接続配線を介して接続され、前記基準電位電極の前記第４の部位と前記第５の部位との間にはギャップが設けられているものである。   The surface acoustic wave element of the present invention is formed on a piezoelectric substrate and a main surface of the piezoelectric substrate, and is arranged in order along the propagation direction of the surface acoustic wave propagating on the main surface of the piezoelectric substrate. A surface acoustic wave device comprising: an IDT electrode; and an annular reference potential electrode formed on a main surface of the piezoelectric substrate so as to surround the first to fifth IDT electrodes. Each of the fifth IDT electrodes has a reference potential bus bar electrode, and the reference potential bus bar electrode of the first IDT electrode is located on an extension in the direction along the propagation direction and on the first IDT electrode side. The reference potential bus bar electrode of the third IDT electrode is connected to the first part of the reference potential electrode via the first connection wiring, and the reference potential is on the extension in the direction orthogonal to the propagation direction. A second connection to the second part of the electrode And the reference potential bus bar electrode of the fifth IDT electrode is a third portion of the reference potential electrode located on the extension of the direction along the propagation direction and on the fifth IDT electrode side. The reference potential bus bar electrode of the second IDT electrode is connected to the first part with a predetermined interval between the first part and the second part. Is connected to a fourth portion on the reference potential electrode separated by a fourth connection wiring, and the reference potential bus bar electrode of the fourth IDT electrode is between the second portion and the third portion. Is connected to a fifth portion on the reference potential electrode that is separated from the third portion by a predetermined distance across the third portion via a fifth connection wiring, and the fourth portion of the reference potential electrode A gap is provided between the fifth portion and the fifth portion.

また本発明の弾性表面波装置は、上記弾性表面波素子と、前記弾性表面波素子が実装される実装基板と、を備えたものである。   The surface acoustic wave device of the present invention includes the surface acoustic wave element and a mounting substrate on which the surface acoustic wave element is mounted.

また本発明の通信装置は、上記弾性表面波装置を有する、受信回路及び送信回路の少なくとも一方を備えたものである。   A communication device of the present invention includes at least one of a reception circuit and a transmission circuit having the surface acoustic wave device.

本発明の弾性表面波素子によれば、第１〜第５のＩＤＴ電極が有するキャパシタ成分と、第１〜第５のＩＤＴ電極と基準電位電極との接続構造によって形成されるインダクタ成分との共振により高周波の減衰極が発現することによって、インダクタ成分が増加し、共振による高周波減衰極の周波数を低く調整することができる。その結果、通過帯域外のより高周波側の帯域外減衰量を大きくすることができる。   According to the surface acoustic wave device of the present invention, the resonance between the capacitor component of the first to fifth IDT electrodes and the inductor component formed by the connection structure of the first to fifth IDT electrodes and the reference potential electrode. As a result, the inductor component increases, and the frequency of the high-frequency attenuation pole due to resonance can be adjusted low. As a result, the out-of-band attenuation on the higher frequency side outside the pass band can be increased.

また本発明の弾性表面波装置は、上記弾性表面波素子と該弾性表面波素子が実装される実装基板とを備えていることにより、通過帯域外のより高周波側の帯域外減衰量を大きくすることができる。   Further, the surface acoustic wave device of the present invention includes the surface acoustic wave element and a mounting substrate on which the surface acoustic wave element is mounted, thereby increasing the out-of-band attenuation on the higher frequency side outside the pass band. be able to.

また本発明の通信装置は上記弾性表面波装置を有する、受信回路及び送信回路の少なくとも一方を備えたことにより、弾性表面波フィルタとしてのカットオフ特性が向上するので、感度が格段に良好な通信装置を実現することができる。   In addition, since the communication device of the present invention includes at least one of the reception circuit and the transmission circuit having the above-described surface acoustic wave device, the cut-off characteristic as the surface acoustic wave filter is improved. An apparatus can be realized.

本発明の一実施形態にかかる弾性表面波装置の斜視図である。1 is a perspective view of a surface acoustic wave device according to an embodiment of the present invention. 図１に示す弾性表面波装置を構成する圧電基板の主面の平面図である。It is a top view of the main surface of the piezoelectric substrate which comprises the surface acoustic wave apparatus shown in FIG. 図１に示す弾性表面波装置を構成する実装基板の主面の平面図である。It is a top view of the main surface of the mounting substrate which comprises the surface acoustic wave apparatus shown in FIG. 本発明の一実施形態にかかる通信装置のブロック図である。It is a block diagram of the communication apparatus concerning one Embodiment of this invention. 比較例の弾性表面波装置を構成する圧電基板の主面の平面図である。It is a top view of the main surface of the piezoelectric substrate which comprises the surface acoustic wave apparatus of a comparative example. 実施例の弾性表面波装置と比較例の弾性表面波装置についての通過特性のシミュレーション結果である。It is the simulation result of the passage characteristic about the surface acoustic wave apparatus of an Example, and the surface acoustic wave apparatus of a comparative example. 図１に示す弾性表面波素子を構成するＩＤＴ電極の拡大平面図である。FIG. 2 is an enlarged plan view of an IDT electrode constituting the surface acoustic wave element shown in FIG. 1. 図１に示す弾性表面波素子を構成するＩＤＴ電極と基準電位電極との接続部分の等価回路図である。FIG. 2 is an equivalent circuit diagram of a connection portion between an IDT electrode and a reference potential electrode constituting the surface acoustic wave element shown in FIG. 1.

以下、本発明の一実施形態にかかる弾性表面波素子、弾性表面波装置および通信装置について図面を参照しつつ詳細に説明する。本実施形態では弾性表面波装置として共振器型の弾性表面波フィルタを例にとり説明する。なお、以下に説明する図面において同一構成の部分には同一符号を付すものとする。また、各電極の大きさや電極間の距離等、電極指の本数や間隔等は、模式的に図示したものであり現実のものとは必ずしも一致しない。   Hereinafter, a surface acoustic wave element, a surface acoustic wave device, and a communication device according to an embodiment of the present invention will be described in detail with reference to the drawings. In this embodiment, a resonator type surface acoustic wave filter will be described as an example of a surface acoustic wave device. In the drawings described below, parts having the same configuration are denoted by the same reference numerals. Further, the number of electrodes, the distance between electrodes, and the like, such as the size of each electrode and the distance between the electrodes, are schematically illustrated and do not necessarily match the actual ones.

図１に本実施形態にかかる弾性表面波装置の斜視図を示す。同図に示すように本実施形態の弾性表面波装置は、弾性表面波素子４０と、弾性表面波素子４０が実装される実装基板２３とから主に構成されている。なお弾性表面波素子４０は全体が封止樹脂２４で被覆されている。図面では便宜上、封止樹脂２４を点線で示している。   FIG. 1 is a perspective view of a surface acoustic wave device according to this embodiment. As shown in the figure, the surface acoustic wave device of this embodiment is mainly composed of a surface acoustic wave element 40 and a mounting substrate 23 on which the surface acoustic wave element 40 is mounted. The entire surface acoustic wave element 40 is covered with the sealing resin 24. In the drawing, the sealing resin 24 is indicated by a dotted line for convenience.

図２に図１に示した弾性表面波素子４０の実装基板２３への実装面側の主面の平面図を示す。弾性表面波素子４０は、圧電基板２２と、圧電基板２２の主面に形成された各種電極とから主に構成されている。より具体的には、第１〜第５のＩＤＴ電極１〜５、弾性表面波共振子１１、入力信号電極８、出力信号電極９、グランド電極１０、基準電位電極１２、ならびにこれらの電極や共振子同士を接続する配線を備えたものである。   FIG. 2 is a plan view of the main surface on the mounting surface side of the surface acoustic wave element 40 shown in FIG. The surface acoustic wave element 40 is mainly composed of the piezoelectric substrate 22 and various electrodes formed on the main surface of the piezoelectric substrate 22. More specifically, the first to fifth IDT electrodes 1 to 5, the surface acoustic wave resonator 11, the input signal electrode 8, the output signal electrode 9, the ground electrode 10, the reference potential electrode 12, and these electrodes and resonances. It is provided with wiring for connecting the children.

第１のＩＤＴ電極１、第２のＩＤＴ電極２、第３のＩＤＴ電極３、第４のＩＤＴ電極４、第５のＩＤＴ電極５は、図７の拡大平面図に示すように、圧電基板２２の主面を伝搬する弾性表面波の伝搬方向に沿って順に配列されている。各ＩＤＴ電極は、伝搬方向に直交する方向に長く伸びる複数の電極指と、電極指同士を接続するバスバー電極１ａ〜５ａとを備えた構成を有している。   As shown in the enlarged plan view of FIG. 7, the first IDT electrode 1, the second IDT electrode 2, the third IDT electrode 3, the fourth IDT electrode 4, and the fifth IDT electrode 5 Are arranged in order along the propagation direction of the surface acoustic wave propagating on the principal surface of the surface. Each IDT electrode has a configuration including a plurality of electrode fingers extending in a direction orthogonal to the propagation direction and bus bar electrodes 1a to 5a connecting the electrode fingers.

これら第１〜第５のＩＤＴ電極の両側には反射器電極６，７が配置されている。反射器電極６，７は、伝搬方向に直交する方向に長く伸びる複数の電極指を備えている。   Reflector electrodes 6 and 7 are disposed on both sides of the first to fifth IDT electrodes. The reflector electrodes 6 and 7 include a plurality of electrode fingers extending long in a direction orthogonal to the propagation direction.

これらのＩＤＴ電極と入力信号端子８との間には、弾性表面波共振子１１が配置されている。弾性表面波共振子１１は、弾性表面波の伝搬方向に直交する方向に長い電極指を複数備えたＩＤＴ電極と、前記ＩＤＴ電極の両側に配置されたと反射器電極とから構成されている。第１〜第５のＩＤＴ電極のうち、第１、第３、第５のＩＤＴと弾性表面波共振子１１とが配線パターンを介して接続されている。   A surface acoustic wave resonator 11 is disposed between these IDT electrodes and the input signal terminal 8. The surface acoustic wave resonator 11 includes an IDT electrode provided with a plurality of electrode fingers that are long in a direction orthogonal to the propagation direction of the surface acoustic wave, and a reflector electrode disposed on both sides of the IDT electrode. Of the first to fifth IDT electrodes, the first, third, and fifth IDTs and the surface acoustic wave resonator 11 are connected via a wiring pattern.

これら第１〜第５のＩＤＴ電極１〜５、弾性表面波共振子１１、各端子などを取り囲むようにして基準電位電極１２が形成されている。基準電位電極１２にはギャップＧが設けられており、完全な環状にはなっていない。第４の部位２８と第５の部位２９とがこのギャップＧの近傍に位置している場合には、このギャップＧの大きさを制御することによって、インダクタ成分を調整することができ、減衰極の制御を簡単に行うことができる。   A reference potential electrode 12 is formed so as to surround the first to fifth IDT electrodes 1 to 5, the surface acoustic wave resonator 11, each terminal, and the like. The reference potential electrode 12 is provided with a gap G and is not a complete ring. When the fourth portion 28 and the fifth portion 29 are located in the vicinity of the gap G, the inductor component can be adjusted by controlling the size of the gap G, and the attenuation pole Can be easily controlled.

図３は実装基板２３の圧電基板２２が実装される側の主面（第１主面２３Ａ）を示す平面図である。実装基板２３はセラミックスなどの絶縁体からなる。実装基板２３の主面には、圧電基板２２の実装面に形成された各種の電極と対応する位置に導体パターンが形成されている。具体的には、圧電基板２２の入力信号電極８と対応する位置には入力信号パッド１４が形成され、圧電基板２２の出力信号電極９と対応する位置には出力信号パッド１５が形成され、圧電基板２２のグランド電極１０と対応する位置にはグランドパッド１６が形成されている。これら入力信号パッド１４、出力信号パッド１５、グランドパッド１６は、それぞれ実装基板２３を厚み方向に貫く貫通導体を介して実装基板２３の下面（第２の主面２３Ｂ）に形成された入力信号端子２０、出力信号端子２１、基準電位端子１９に接続されている（図１参照）。なお本実施形態において基準電位とはグランド電位のことであるが、かならずしも０ボルトである必要はない。   FIG. 3 is a plan view showing the main surface (first main surface 23A) of the mounting substrate 23 on the side where the piezoelectric substrate 22 is mounted. The mounting substrate 23 is made of an insulator such as ceramics. On the main surface of the mounting substrate 23, conductor patterns are formed at positions corresponding to various electrodes formed on the mounting surface of the piezoelectric substrate 22. Specifically, an input signal pad 14 is formed at a position corresponding to the input signal electrode 8 of the piezoelectric substrate 22, and an output signal pad 15 is formed at a position corresponding to the output signal electrode 9 of the piezoelectric substrate 22. A ground pad 16 is formed at a position corresponding to the ground electrode 10 of the substrate 22. These input signal pad 14, output signal pad 15, and ground pad 16 are input signal terminals formed on the lower surface (second main surface 23B) of the mounting substrate 23 through through conductors that penetrate the mounting substrate 23 in the thickness direction. 20, connected to an output signal terminal 21 and a reference potential terminal 19 (see FIG. 1). In the present embodiment, the reference potential is a ground potential, but is not necessarily 0 volts.

また基準電位電極１２と接続される所定の位置には、基準電位パッド１７，１８が形成され、これら基準電位パッド１７，１８の直下には第１の基準電位貫通導体１７ａと、第２の基準電位貫通導体１８ａがそれぞれ形成されている。第１の基準電位貫通導体１７ａおよび第２の基準電位貫通導体１８ａは実装基板２３を厚み方向に貫く貫通導体である。第１の基準電位貫通導体１７ａ、第２の基準電位貫通導体１８ａは、実装基板２３の下面に形成された基準電位端子１９にそれぞれ接続されている。第１の基準電位貫通導体１７ａ、第２の基準電位貫通導体１８ａは、例えば、実装基板２３の第１の主面２３Ａと第２の主面２３Ｂとを貫通する貫通孔にＡｇなどの導体を充填することにより形成される。第１の基準電位貫通導体１７ａ、第２の基準電位貫通導体１８ａの直径は５０〜１００μｍ程度である。   Reference potential pads 17 and 18 are formed at predetermined positions connected to the reference potential electrode 12. The first reference potential through conductor 17 a and the second reference potential pad 17 and 18 are formed immediately below the reference potential pads 17 and 18. A potential through conductor 18a is formed. The first reference potential through conductor 17a and the second reference potential through conductor 18a are through conductors that penetrate the mounting substrate 23 in the thickness direction. The first reference potential through conductor 17a and the second reference potential through conductor 18a are connected to a reference potential terminal 19 formed on the lower surface of the mounting substrate 23, respectively. The first reference potential through conductor 17a and the second reference potential through conductor 18a are made of, for example, a conductor such as Ag in a through hole that penetrates the first main surface 23A and the second main surface 23B of the mounting substrate 23. It is formed by filling. The diameters of the first reference potential through conductor 17a and the second reference potential through conductor 18a are about 50 to 100 μm.

図２には、第１の基準貫通導体１７ａと対応する位置に点線で１７’を、第２の基準電位貫通導体１８ａと対応する位置に点線で１８’を示してある。図２に示すように、第１の基準電位貫通導体１７ａは、基準電位電極１２の第１の部位２５と第４の部位２８との間に形成されている。一方、第２の基準電位貫通導体１８ａは、基準電位電極１２の第３の部位２７と第５の部位２９との間に形成されている。   In FIG. 2, 17 'is indicated by a dotted line at a position corresponding to the first reference through conductor 17a, and 18' is indicated by a dotted line at a position corresponding to the second reference potential through conductor 18a. As shown in FIG. 2, the first reference potential through conductor 17 a is formed between the first portion 25 and the fourth portion 28 of the reference potential electrode 12. On the other hand, the second reference potential penetrating conductor 18 a is formed between the third portion 27 and the fifth portion 29 of the reference potential electrode 12.

次にこれら第１〜第５のＩＤＴ電極１〜５の基準電位バスバー電極１ａ〜５ａと基準電位電極１２との接続構造について説明する。   Next, a connection structure between the reference potential bus bar electrodes 1a to 5a of the first to fifth IDT electrodes 1 to 5 and the reference potential electrode 12 will be described.

まず第１のＩＤＴ電極１の基準電位バスバー電極１ａは、弾性表面波の伝搬方向に沿った方向の延長上で且つ第１のＩＤＴ電極１側に位置する基準電位電極１２の第１の部位２５に第１の接続配線３０を介して接続されている。第３のＩＤＴ電極３の基準電位バスバー電極３ａは、弾性表面波の伝搬方向に直交する方向の延長上にある基準電位電極１２の第２の部位２６に第２の接続配線３１を介して接続されている。第５のＩＤＴ電極５の基準電位バスバー電極５ａは、弾性表面波の伝搬方向に沿った方向の延長上で且つ第５のＩＤＴ電極５側に位置する基準電位電極１２の第３の部位２７に第３の接続配線３２を介して接続されている。第２のＩＤＴ電極２の基準電位バスバー電極２ａは、第２の部位２６との間に第１の部位２５を挟んで第１の部位２５と所定間隔だけ離れた基準電位電極１２上のギャップＧの近傍に位置する第４の部位２８に第４の接続配線３３を介して接続されている。第４のＩＤＴ電極４の基準電位バスバー電極４ａは、第２の部位２６との間に第３の部位を挟んで第３の部位と所定間隔だけ離れた基準電位電極１２上のギャップＧの近傍に位置する第５の部位２９に第５の接続配線３４を介して接続されている。換言すれば、基準電位電極１２の第４の部位２８と第５の部位２９との間にギャップＧが設けられている。   First, the reference potential bus bar electrode 1a of the first IDT electrode 1 is a first portion 25 of the reference potential electrode 12 located on the first IDT electrode 1 side on the extension in the direction along the propagation direction of the surface acoustic wave. Are connected to each other via a first connection wiring 30. The reference potential bus bar electrode 3a of the third IDT electrode 3 is connected to the second portion 26 of the reference potential electrode 12 on the extension in the direction orthogonal to the propagation direction of the surface acoustic wave via the second connection wiring 31. Has been. The reference potential bus bar electrode 5a of the fifth IDT electrode 5 is formed on the third portion 27 of the reference potential electrode 12 on the extension of the direction along the propagation direction of the surface acoustic wave and on the fifth IDT electrode 5 side. The third connection wiring 32 is connected. The reference potential bus bar electrode 2a of the second IDT electrode 2 has a gap G on the reference potential electrode 12 that is spaced apart from the first part 25 by a predetermined distance with the first part 25 interposed between the second part 26 and the second potential part 26. Is connected via a fourth connection wiring 33 to a fourth portion 28 located in the vicinity of. The reference potential bus bar electrode 4a of the fourth IDT electrode 4 is in the vicinity of the gap G on the reference potential electrode 12 that is spaced apart from the third portion by a predetermined distance with the third portion interposed between the second portion 26 and the third potential portion. Is connected via a fifth connection wiring 34 to the fifth portion 29 located at the position. In other words, the gap G is provided between the fourth portion 28 and the fifth portion 29 of the reference potential electrode 12.

基準電位電極１２と各基準電位バスバー電極１ａ〜５ａとがこのような接続構造を有していることにより、周波数帯域外の高周波側に減衰極が形成され、通貨帯域外の高周波側における帯域減衰量を大きくすることができる。これは、それぞれの基準電位バスバー電極１ａ〜５ａと基準電位電極１２とが、第１〜第５の接続配線３０〜３４で接続されることによって、第１〜第５の接続配線３０〜３４による比較的大きなインダクタ成分が発現するためである。この場合、ＩＤＴ電極の交差幅や対数などの設計変更といった複雑な作業を行うことなく配線パターンだけで減衰極の周波数調整をすることができ、通過帯域近傍の帯域外減衰量に与える影響を小さく抑えた上でより高周波側の帯域外減衰量を大きくすることができる。   Since the reference potential electrode 12 and each reference potential bus bar electrode 1a to 5a have such a connection structure, an attenuation pole is formed on the high frequency side outside the frequency band, and the band attenuation on the high frequency side outside the currency band. The amount can be increased. This is because the respective reference potential bus bar electrodes 1a to 5a and the reference potential electrode 12 are connected by the first to fifth connection wirings 30 to 34, whereby the first to fifth connection wirings 30 to 34 are used. This is because a relatively large inductor component appears. In this case, the frequency of the attenuation pole can be adjusted only by the wiring pattern without performing complicated work such as the design change of the IDT electrode intersection width and logarithm, and the influence on the out-of-band attenuation near the passband is reduced. In addition, the out-of-band attenuation on the high frequency side can be increased.

ここで第１、第２のＩＤＴ電極１，２の基準電位電極１２への接続構造に着目すると、第１のＩＤＴ電極１の基準電位バスバー電極１ａと基準電位電極１２とを接続する第１の接続配線３０によってインダクタＬ１が形成され、さらに第１の部位２５と第４の部位２８との間の基準電位電極１２、第４の部位２８と第２のＩＤＴ電極２の基準電位バスバー電極２ａとを接続する第４の接続配線３３、および第２のＩＤＴ電極２と第１のＩＤＴ電極１との容量結合によってループ回路によるインダクタＬ２が形成されることとなる。このループ回路上の合成ＣとインダクタＬ２の共振によって高周波減衰極が形成される。第１のＩＤＴ電極と基準電位バスバー電極１ａと基準電位電極１２とを接続する接続配線３０によるインダクタＬ１とループ回路上の第１のＩＤＴと第２のＩＤＴ電極の合成容量とインダクタＬ２によって複数の減衰極が発生し、第１のＩＤＴ電極１と第２のＩＤＴ電極２との合成容量が、第１のＩＤＴ電極１による容量Ｃ１より十分小さくなると、通過周波数帯域近傍の減衰特性を維持しつつ、高周波の減衰極を移動させることができる。その結果、通過帯域外のより高周波側の帯域外減衰量を大きくすることができる。なお、本実施形態では、第４、第５のＩＤＴ電極４，５と基準電位電極１２との接続構造においても同様のループ回路が形成されている。上記回路の等価回路を図８に示す。上記第１のＩＤＴ電極容量は図８のＣ１に相当し、ループ回路の合成容量はＣ２に相当する。また前記第１の接続配線インダクタＬ１は図８のＬ１に相当し、ループ回路上の配線インダクタＬ２は図８のＬ２に相当している。   Here, paying attention to the connection structure of the first and second IDT electrodes 1 and 2 to the reference potential electrode 12, the first potential connecting the reference potential bus bar electrode 1 a of the first IDT electrode 1 and the reference potential electrode 12 is the first. The inductor L1 is formed by the connection wiring 30, and further, the reference potential electrode 12 between the first portion 25 and the fourth portion 28, the reference potential bus bar electrode 2a of the fourth portion 28 and the second IDT electrode 2, and As a result of the capacitive coupling between the second IDT electrode 2 and the first IDT electrode 1, the inductor L2 is formed by a loop circuit. A high frequency attenuation pole is formed by the resonance of the composite C and the inductor L2 on the loop circuit. The inductor L1 by the connection wiring 30 that connects the first IDT electrode, the reference potential bus bar electrode 1a, and the reference potential electrode 12, the combined capacitance of the first IDT and second IDT electrodes on the loop circuit, and the inductor L2 make it possible to When an attenuation pole is generated and the combined capacitance of the first IDT electrode 1 and the second IDT electrode 2 is sufficiently smaller than the capacitance C1 of the first IDT electrode 1, the attenuation characteristic in the vicinity of the pass frequency band is maintained. The high frequency attenuation pole can be moved. As a result, the out-of-band attenuation on the higher frequency side outside the pass band can be increased. In the present embodiment, a similar loop circuit is also formed in the connection structure between the fourth and fifth IDT electrodes 4 and 5 and the reference potential electrode 12. An equivalent circuit of the above circuit is shown in FIG. The first IDT electrode capacitance corresponds to C1 in FIG. 8, and the combined capacitance of the loop circuit corresponds to C2. The first connection wiring inductor L1 corresponds to L1 in FIG. 8, and the wiring inductor L2 on the loop circuit corresponds to L2 in FIG.

本実施形態において、第２、第４、第５の接続配線３１，３３，３４はそれぞれ立体配線構造となっている。たとえば第２の接続配線３１は、第２のＩＤＴ電極２と出力電極９とを接続する配線パターンと交差するが、この交差部分における両者の間には絶縁層３３が介在されている。第４、第５の接続配線３３，３４も同様に絶縁層３３を間に挟むことで立体配線を実現している。このように立体配線構造とすることで、配線を高密度に配置することができ弾性表面波素子を小型化することができる。   In the present embodiment, the second, fourth, and fifth connection wirings 31, 33, and 34 each have a three-dimensional wiring structure. For example, the second connection wiring 31 intersects with a wiring pattern that connects the second IDT electrode 2 and the output electrode 9, and an insulating layer 33 is interposed between the two at the intersection. Similarly, the fourth and fifth connection wirings 33 and 34 also realize three-dimensional wiring by sandwiching the insulating layer 33 therebetween. By adopting such a three-dimensional wiring structure, the wiring can be arranged with high density, and the surface acoustic wave element can be miniaturized.

また、第１、第３、第５のＩＤＴ電極１、３、５は入力電極８に接続されており、第２、第４のＩＤＴ電極２、４は出力電極９に接続されている。   The first, third, and fifth IDT electrodes 1, 3, and 5 are connected to the input electrode 8, and the second and fourth IDT electrodes 2 and 4 are connected to the output electrode 9.

また、圧電基板２２の各電極と実装基板２３の対応するパッドとは、はんだなどの導電性接合材を介して接続されている。また、弾性表面波素子４０を覆う封止樹脂２４によって圧電基板２２の主面に形成された各種電極が封止されている。   In addition, each electrode of the piezoelectric substrate 22 and a corresponding pad of the mounting substrate 23 are connected via a conductive bonding material such as solder. Various electrodes formed on the main surface of the piezoelectric substrate 22 are sealed with a sealing resin 24 that covers the surface acoustic wave element 40.

次に、本実施形態にかかる弾性表面波素子４０および弾性表面波装置の製造方法について説明する。   Next, a method for manufacturing the surface acoustic wave element 40 and the surface acoustic wave device according to the present embodiment will be described.

弾性表面波素子４０の作製方法は、まず圧電基板２２の主面に第１〜第５ＩＤＴ電極１〜５、反射器電極６，７、基準電位電極１２、入出力電極８，９、グランド電極１０、第１〜第５の接続配線３０〜３４、弾性表面波共振子１１等を形成する。これらの電極や配線パターンは、ＡｌもしくはＡｌ合金（Ａｌ−Ｃｕ系、Ａｌ−Ｔｉ系）などの導電性材料からなり、蒸着法、スパッタリング法、またはＣＶＤ法等の薄膜形成法により製膜した後、フォトリソグラフィ法などによりパターニングすることで形成される。これらの電極や配線パターンの厚みは、例えば０．１〜０．３μｍ程度である。   A method of manufacturing the surface acoustic wave element 40 is as follows. First to fifth IDT electrodes 1 to 5, reflector electrodes 6 and 7, reference potential electrode 12, input / output electrodes 8 and 9, and ground electrode 10 on the main surface of the piezoelectric substrate 22. The first to fifth connection wirings 30 to 34, the surface acoustic wave resonator 11 and the like are formed. These electrodes and wiring patterns are made of a conductive material such as Al or an Al alloy (Al-Cu type, Al-Ti type), and are formed by a thin film forming method such as a vapor deposition method, a sputtering method, or a CVD method. It is formed by patterning by a photolithography method or the like. The thickness of these electrodes and wiring patterns is, for example, about 0.1 to 0.3 μm.

次に、ＩＤＴ電極の各種電極を覆って保護するための絶縁膜を成膜する。絶縁膜の材料としては、Ｓｉ，ＳｉＯ2，ＳｉＮx，Ａｌ2Ｏ3等を用いることができる。その成膜方法としては、スパッタリング法、ＣＶＤ（Chemical Vapor Deposition）法、電子ビーム蒸着法等を用いることができる。 Next, an insulating film for covering and protecting various electrodes of the IDT electrode is formed. As the material of the insulating film, Si, SiO 2 , SiN x , Al 2 O 3 or the like can be used. As the film formation method, a sputtering method, a CVD (Chemical Vapor Deposition) method, an electron beam evaporation method, or the like can be used.

なお、ＩＤＴ電極、反射器電極において、電極指の本数は数本〜数１００本にも及ぶので、簡単のため、図においてはそれらの形状を簡略化して図示している。   In the IDT electrode and the reflector electrode, the number of electrode fingers ranges from several to several hundreds. Therefore, for the sake of simplicity, these shapes are simplified in the drawing.

また、弾性表面波素子の圧電基板２２としては、３６°±３°ＹカットＸ伝搬タンタル酸リチウム単結晶、４２°±３°ＹカットＸ伝搬タンタル酸リチウム単結晶、６４°±３°ＹカットＸ伝搬ニオブ酸リチウム単結晶、４１°±３°ＹカットＸ伝搬ニオブ酸リチウム単結晶、４５°±３°ＸカットＺ伝搬四ホウ酸リチウム単結晶は電気機械結合係数が大きく、かつ、周波数温度係数が小さいため、圧電基板２２として好ましい。また、これらの焦電性圧電単結晶のうち、酸素欠陥やＦｅ等の固溶により焦電性を著しく減少させた圧電基板１であれば、弾性表面波素子の信頼性上良好である。圧電基板１の厚みは、例えば０．１〜０．５ｍｍ程度がよく、０．１ｍｍ未満では圧電基板２３が脆くなり、０．５ｍｍを超えると材料コストと部品寸法が大きくなり好ましくない。   As the piezoelectric substrate 22 of the surface acoustic wave element, 36 ° ± 3 ° Y-cut X-propagation lithium tantalate single crystal, 42 ° ± 3 ° Y-cut X-propagation lithium tantalate single crystal, 64 ° ± 3 ° Y-cut X-propagating lithium niobate single crystal, 41 ° ± 3 ° Y-cut X-propagating lithium niobate single crystal, 45 ° ± 3 ° X-cut Z-propagating lithium tetraborate single crystal has a large electromechanical coupling coefficient and frequency temperature Since the coefficient is small, it is preferable as the piezoelectric substrate 22. Of these pyroelectric piezoelectric single crystals, if the piezoelectric substrate 1 has a significantly reduced pyroelectric property due to solid solution of oxygen defects, Fe, or the like, the reliability of the surface acoustic wave element is good. The thickness of the piezoelectric substrate 1 is preferably about 0.1 to 0.5 mm, for example. If the thickness is less than 0.1 mm, the piezoelectric substrate 23 becomes brittle, and if it exceeds 0.5 mm, the material cost and component dimensions increase, which is not preferable.

このような弾性表面波素子４０を、基準電位電極１２と対応する基準導体パターン１３が形成された実装基板２３に実装する。弾性表面波素子４０の実装基板２３への実装は、基準電位電極１２と基準導体パターン１３とを間にはんだ等の接合在を介して接合することにより行われる。最後に弾性表面波素子４０全体を覆う封止樹脂２４を形成する。封止樹脂２４は、例えばエポキシ樹脂などからなる樹脂材料を弾性表面波素子４０を覆うように塗布し、これを硬化させることにより作製される。このようにして製品としての弾性表面波装置が完成する。   Such a surface acoustic wave element 40 is mounted on a mounting substrate 23 on which a reference conductor pattern 13 corresponding to the reference potential electrode 12 is formed. The surface acoustic wave element 40 is mounted on the mounting substrate 23 by joining the reference potential electrode 12 and the reference conductor pattern 13 with a solder or the like interposed therebetween. Finally, a sealing resin 24 that covers the entire surface acoustic wave element 40 is formed. The sealing resin 24 is manufactured by applying a resin material made of, for example, an epoxy resin so as to cover the surface acoustic wave element 40 and curing it. Thus, the surface acoustic wave device as a product is completed.

〔通信装置〕
本実施形態の通信装置は、上述した弾性表面波装置を有する、受信回路及び送信回路の少なくとも一方を備えたことにより、弾性表面波フィルタのカットオフ特性を向上させることができるので、感度が格段に良好な通信装置を実現することができる。 〔Communication device〕
Since the communication device according to the present embodiment includes at least one of the reception circuit and the transmission circuit having the above-described surface acoustic wave device, the cutoff characteristic of the surface acoustic wave filter can be improved. An excellent communication device can be realized.

即ち、少なくとも受信回路または送信回路の一方を備え、弾性表面波装置をこれらの回路に含まれるバンドパスフィルタとして用いる。例えば、送信回路から出力された送信信号をミキサでキャリア周波数にのせて、不要信号をバンドパスフィルタで減衰させ、その後、パワーアンプで送信信号を増幅して、デュプレクサを通ってアンテナより送信することができる送信回路を備えた通信装置、または、受信信号をアンテナで受信し、デュプレクサを通った受信信号をローノイズアンプで増幅し、その後、バンドパスフィルタで不要信号を減衰して、ミキサでキャリア周波数から信号を分離し、この信号を取り出す受信回路へ伝送するような受信回路を備えた通信装置に適用可能である。   That is, at least one of a receiving circuit and a transmitting circuit is provided, and the surface acoustic wave device is used as a bandpass filter included in these circuits. For example, the transmission signal output from the transmission circuit is put on the carrier frequency by the mixer, the unnecessary signal is attenuated by the band pass filter, and then the transmission signal is amplified by the power amplifier and transmitted from the antenna through the duplexer. A communication device equipped with a transmission circuit capable of receiving signals or receiving a received signal with an antenna, amplifying the received signal that has passed through the duplexer with a low-noise amplifier, and then attenuating an unnecessary signal with a band-pass filter, and a carrier frequency with a mixer Can be applied to a communication apparatus including a receiving circuit that separates a signal from the signal and transmits the signal to a receiving circuit that extracts the signal.

図４は、本実施形態の通信装置を示すブロック回路図である。図４において、アンテナ１４０に送信回路Ｔｘと受信回路Ｒｘが分波器１５０を介して接続されている。送信される高周波信号は、フィルタ２１０によりその不要信号が除去され、パワーアンプ２２０で増幅された後、アイソレータ２３０と分波器１５０を通り、アンテナ１４０から放射される。また、アンテナ１４０で受信された高周波信号は、分波器１５０を通りローノイズアンプ１６０で増幅されフィルタ１７０でその不要信号を除去された後、アンプ１８０で再増幅されミキサ１９０で低周波信号に変換される。   FIG. 4 is a block circuit diagram showing the communication apparatus of this embodiment. In FIG. 4, a transmission circuit Tx and a reception circuit Rx are connected to an antenna 140 via a duplexer 150. The high-frequency signal to be transmitted is removed from the unnecessary signal by the filter 210, amplified by the power amplifier 220, and then radiated from the antenna 140 through the isolator 230 and the duplexer 150. The high-frequency signal received by the antenna 140 is amplified by the low-noise amplifier 160 through the duplexer 150, the unnecessary signal is removed by the filter 170, re-amplified by the amplifier 180, and converted to a low-frequency signal by the mixer 190. Is done.

従って、本実施の形態の弾性表面波装置を採用すれば、感度が格段に良好な優れた通信装置を提供できる。   Therefore, if the surface acoustic wave device according to the present embodiment is employed, an excellent communication device with remarkably good sensitivity can be provided.

本発明の弾性表面波装置の実施例について以下に説明する。図１に示す弾性表面波装置を具体的に作製した実施例について説明する。   Examples of the surface acoustic wave device of the present invention will be described below. A specific example of the surface acoustic wave device shown in FIG. 1 will be described.

３８．７°ＹカットのＸ方向伝搬とするＬｉＴａＯ3単結晶からなる圧電基板２２上に、Ａｌ（９９質量％）−Ｃｕ（１質量％）合金から成る、ＩＤＴ電極１〜５及び反射器電極６，７を有する弾性表面波素子、基準電位電極１１、入出力電極８，９、グランド電極１０、第１〜第３配線パターン３０，３１，３２を形成した。これら電極や配線パターンの作製は、スパッタリング装置、縮小投影露光機（ステッパー）、及びＲＩＥ（Reactive Ion Etching）装置によりフォトリソグラフィを施すことにより行った。 IDT electrodes 1 to 5 and reflector electrodes made of an Al (99 mass%)-Cu (1 mass%) alloy on a piezoelectric substrate 22 made of a LiTaO 3 single crystal with X-propagation of 38.7 ° Y-cut. The surface acoustic wave element having 6 and 7, the reference potential electrode 11, the input / output electrodes 8 and 9, the ground electrode 10, and the first to third wiring patterns 30, 31 and 32 were formed. These electrodes and wiring patterns were produced by photolithography using a sputtering apparatus, a reduction projection exposure machine (stepper), and an RIE (Reactive Ion Etching) apparatus.

まず、圧電基板２２をアセトン，ＩＰＡ（イソプロピルアルコール）等によって超音波洗浄し、有機成分を落とした。次に、クリーンオーブンによって充分に圧電基板２２の乾燥を行った後、各電極や配線パターンとなる金属層の成膜を行った。金属層の成膜にはスパッタリング装置を使用し、金属層の材料としてＡｌ（９９質量％）−Ｃｕ（１質量％）合金を用いた。このときの金属層の厚みは約０．１５μｍとした。   First, the piezoelectric substrate 22 was ultrasonically cleaned with acetone, IPA (isopropyl alcohol) or the like to remove organic components. Next, after sufficiently drying the piezoelectric substrate 22 with a clean oven, a metal layer serving as each electrode and wiring pattern was formed. A sputtering apparatus was used for forming the metal layer, and an Al (99 mass%)-Cu (1 mass%) alloy was used as the material of the metal layer. The thickness of the metal layer at this time was about 0.15 μm.

次に、金属層上にフォトレジストを約０．５μｍの厚みにスピンコートし、縮小投影露光装置（ステッパー）により、所望形状にパターニングを行い、現像装置によって不要部分のフォトレジストをアルカリ現像液で溶解させ、所望パターンを表出させた。その後、ＲＩＥ装置により金属層のエッチングを行い、パターニングを終了し、弾性表面波素子４０を構成する各電極のパターンを得た。このときの電極パターンは、図５（ａ）に示すとおりである。   Next, a photoresist is spin-coated on the metal layer to a thickness of about 0.5 μm, patterned into a desired shape by a reduction projection exposure apparatus (stepper), and an unnecessary portion of photoresist is developed with an alkaline developer by a developing apparatus. Dissolve to reveal the desired pattern. Thereafter, the metal layer was etched by an RIE apparatus, patterning was completed, and a pattern of each electrode constituting the surface acoustic wave element 40 was obtained. The electrode pattern at this time is as shown in FIG.

この後、各電極や配線パターンの所定領域上にＣＶＤ法により、ＳｉＯ2膜からなる保護膜を形成した。なお保護膜の厚みは０．０１５μｍに設定した。 Thereafter, a protective film made of a SiO 2 film was formed on a predetermined region of each electrode and wiring pattern by a CVD method. The thickness of the protective film was set to 0.015 μm.

その後、フォトリソグラフィによりパターニングを行い、ＲＩＥ装置等でフリップチップ用窓開け部のエッチングを行った。その後、そのフリップチップ用窓開け部に、スパッタリング装置を使用して、Ｃｒ層、Ｎｉ層、Ａｕ層を積層した構成のパッド電極を成膜した。このときのパッド電極の厚みは１．０μｍとした。   Thereafter, patterning was performed by photolithography, and the flip-chip window opening portion was etched by an RIE apparatus or the like. Thereafter, a pad electrode having a structure in which a Cr layer, a Ni layer, and an Au layer were stacked was formed on the flip-chip window opening using a sputtering apparatus. The thickness of the pad electrode at this time was 1.0 μm.

その後、圧電基板２２の基準電位電極１２の電極と実装基板２３のパッドとをはんだを用いて接続することにより圧電基板２２を実装基板２３に実装した。なお実装基板２３の第１、第２基準電位貫通導体１７ａ，１８ａは、実装基板２３の下面に形成した基準電用端子１９接続されるようにした。その後、Ｎ2ガス雰囲気中でベーキングを行い、パッケージ化された弾性表面波装置を完成した。 After that, the piezoelectric substrate 22 was mounted on the mounting substrate 23 by connecting the electrode of the reference potential electrode 12 of the piezoelectric substrate 22 and the pad of the mounting substrate 23 using solder. The first and second reference potential through conductors 17a and 18a of the mounting substrate 23 are connected to the reference voltage terminal 19 formed on the lower surface of the mounting substrate 23. Thereafter, baking was performed in an N 2 gas atmosphere to complete a packaged surface acoustic wave device.

（比較例）
比較例のサンプルとして、図５（ｂ）に示す構成からなる弾性表面波装置を作製した。この弾性表面波装置の作製方法は上記実施例と同様である。 (Comparative example)
As a sample of the comparative example, a surface acoustic wave device having the configuration shown in FIG. The method for manufacturing the surface acoustic wave device is the same as in the above embodiment.

実施例の弾性表面波素子４０では、第１、第３、第５のＩＤＴ電極１，３，５の基準電位バスバー電極１ａ、３ａ、５ａを基準電位電極１２に接続したのに対し、図５に示す比較例の弾性表面波素子は、第１、第３、第５のＩＤＴ電極１，３，５の基準電位バスバー電極１ａ、３ａ、５ａを、基準電位電極１２ではなく、グランド電極１０に接続している。その他の構成は、図１の弾性表面波素子と同様である。   In the surface acoustic wave device 40 of the embodiment, the reference potential bus bar electrodes 1a, 3a, and 5a of the first, third, and fifth IDT electrodes 1, 3, and 5 are connected to the reference potential electrode 12, whereas FIG. In the surface acoustic wave device of the comparative example shown in FIG. 1, the reference potential bus bar electrodes 1a, 3a, and 5a of the first, third, and fifth IDT electrodes 1, 3, and 5 are connected to the ground electrode 10 instead of the reference potential electrode 12. Connected. Other configurations are the same as those of the surface acoustic wave device of FIG.

次に、本実施例及び比較例の弾性表面波装置について、それぞれの特性をコンピュータシミュレーションによって求めた。弾性表面波装置の動作周波数は５００ＭＨｚ以上８０００ＭＨｚ以下とした。この動作周波数における周波数特性のグラフを図６に示す。図６は、フィルタの伝送特性を表す透過特性（減衰量）の周波数依存性を示すグラフである。   Next, the characteristics of the surface acoustic wave devices of this example and the comparative example were obtained by computer simulation. The operating frequency of the surface acoustic wave device was 500 MHz or more and 8000 MHz or less. A graph of frequency characteristics at this operating frequency is shown in FIG. FIG. 6 is a graph showing the frequency dependence of the transmission characteristic (attenuation amount) representing the transmission characteristic of the filter.

本実施例の弾性表面波装置のフィルタ特性は非常に良好であった。即ち、図６の破線で示した比較例の弾性表面波装置と比較して、図６の実線で示すように、６ＧＨｚ付近の高周波数において、本実施例の弾性表面波装置の帯域外減衰量が非常に大きいことが確認できた。   The filter characteristics of the surface acoustic wave device of this example were very good. That is, as compared with the surface acoustic wave device of the comparative example shown by the broken line in FIG. 6, as shown by the solid line in FIG. 6, the out-of-band attenuation of the surface acoustic wave device of the present embodiment at a high frequency near 6 GHz. Was found to be very large.

１〜５：第１〜第５のＩＤＴ電極
６，７：反射器電極
８：入力信号電極
９：出力信号電極
１０：グランド電極
１１：弾性表面波共振子
２５〜２９：基準電位電極の第１〜第５の部位
３０〜３４：第１〜第５の接続配線 1 to 5: First to fifth IDT electrodes 6 and 7: Reflector electrode 8: Input signal electrode 9: Output signal electrode 10: Ground electrode 11: Surface acoustic wave resonators 25 to 29: First reference potential electrode -5th site | parts 30-34: 1st-5th connection wiring

Claims (6)

圧電基板と、前記圧電基板の主面に形成され、前記圧電基板の主面を伝搬する弾性表面波の伝搬方向に沿って順に配列された第１乃至第５のＩＤＴ電極と、前記圧電基板の主面に前記第１乃至第５のＩＤＴ電極を取り囲むように形成された環状の基準電位電極と、を有する弾性表面波素子と、
第１の主面を有し、該第１の主面に対して前記圧電基板の主面が向き合うようにして前記弾性表面波素子が実装された実装基板と、を備えた弾性表面波装置であって、
前記第１乃至第５のＩＤＴ電極は、それぞれ基準電位バスバー電極を有し、
前記第１のＩＤＴ電極の基準電位バスバー電極は、前記伝搬方向に沿った方向の延長上で且つ前記第１のＩＤＴ電極側に位置する前記基準電位電極の第１の部位に第１の接続配線を介して接続され、
前記第３のＩＤＴ電極の基準電位バスバー電極は、前記伝搬方向に直交する方向の延長上にある前記基準電位電極の第２の部位に第２の接続配線を介して接続され、
前記第５のＩＤＴ電極の基準電位バスバー電極は、前記伝搬方向に沿った方向の延長上で且つ前記第５のＩＤＴ電極側に位置する前記基準電位電極の第３の部位に第３の接続配線を介して接続され、
前記第２のＩＤＴ電極の基準電位バスバー電極は、前記第２の部位との間に前記第１の部位を挟んで該第１の部位と所定間隔だけ離れた前記基準電位電極上の第４の部位に第４の接続配線を介して接続され、
前記第４のＩＤＴ電極の基準電位バスバー電極は、前記第２の部位との間に前記第３の部位を挟んで該第３の部位と所定間隔だけ離れた前記基準電位電極上の第５の部位に第５の接続配線を介して接続され、
前記基準電位電極の前記第４の部位と前記第５の部位との間にはギャップが設けられており、
前記第１のＩＤＴ電極は前記第２のＩＤＴ電極と容量結合し、
前記第４のＩＤＴ電極は前記第５のＩＤＴ電極と容量結合し、
前記実装基板は、前記基準電位電極のうち前記第１の部位と前記第４の部位との間の部分に接続された第１の基準電位貫通導体および前記基準電位電極のうち前記第３の部位と前記第５の部位との間の部分に接続された第２の基準電位貫通導体を有している弾性表面波装置。 A piezoelectric substrate; first to fifth IDT electrodes formed on a main surface of the piezoelectric substrate and arranged in order along a propagation direction of a surface acoustic wave propagating through the main surface of the piezoelectric substrate; and A surface acoustic wave element having an annular reference potential electrode formed on a main surface so as to surround the first to fifth IDT electrodes ;
A surface acoustic wave device comprising: a mounting substrate having a first principal surface, wherein the surface acoustic wave element is mounted so that the principal surface of the piezoelectric substrate faces the first principal surface . There,
The first to 5 IDT electrode has a reference potential bus bar electrode, respectively,
The reference potential bus bar electrode of the first IDT electrode is connected to the first portion of the reference potential electrode located on the first IDT electrode side on the extension in the direction along the propagation direction. Connected through
A reference potential bus bar electrode of the third IDT electrode is connected to a second portion of the reference potential electrode on an extension in a direction orthogonal to the propagation direction via a second connection wiring,
The reference potential bus bar electrode of the fifth IDT electrode is connected to the third portion of the reference potential electrode on the extension of the direction along the propagation direction and on the fifth IDT electrode side. Connected through
The reference potential bus bar electrode of the second IDT electrode has a fourth potential on the reference potential electrode spaced apart from the first part by a predetermined distance with the first part sandwiched between the second part and the second part. Connected to the part via the fourth connection wiring,
The reference potential bus bar electrode of the fourth IDT electrode includes a fifth potential on the reference potential electrode spaced apart from the third portion by a predetermined distance with the third portion sandwiched between the second portion and the second potential portion. Connected to the site via the fifth connection wiring,
A gap is provided between the fourth part and the fifth part of the reference potential electrode ,
The first IDT electrode is capacitively coupled to the second IDT electrode;
The fourth IDT electrode is capacitively coupled to the fifth IDT electrode;
The mounting substrate includes a first reference potential penetrating conductor connected to a portion between the first portion and the fourth portion of the reference potential electrode, and the third portion of the reference potential electrode. And a surface acoustic wave device having a second reference potential through conductor connected to a portion between the first portion and the fifth portion . 前記第２の接続配線は、前記第３のＩＤＴ電極の基準電位バスバー電極から前記伝搬方向と直交する方向に伸びている請求項１に記載の弾性表面波装置。 2. The surface acoustic wave device according to claim 1, wherein the second connection wiring extends from a reference potential bus bar electrode of the third IDT electrode in a direction orthogonal to the propagation direction. 前記圧電基板の主面に形成された入出力信号端子をさらに備え、
前記入出力信号端子と前記第１〜第５のＩＤＴ電極との間に、弾性表面波共振子が接続されている請求項１に記載の弾性表面波装置。 It further comprises an input / output signal terminal formed on the main surface of the piezoelectric substrate,
The surface acoustic wave device according to claim 1, wherein a surface acoustic wave resonator is connected between the input / output signal terminal and the first to fifth IDT electrodes. 前記第４の接続配線は前記第１の接続配線よりも長く、前記第５の接続配線は前記第３の接続配線よりも長い請求項１乃至３のいずれか１項に記載の弾性表面波装置。 4. The surface acoustic wave device according to claim 1, wherein the fourth connection wiring is longer than the first connection wiring, and the fifth connection wiring is longer than the third connection wiring. 5. . 前記弾性表面波素子は、前記伝搬方向に沿った方向において前記第１乃至第５のＩＤＴ電極を挟む位置に配置された一対の反射器電極を有する請求項１乃至４のいずれか１項に記載の弾性表面波装置。 The said surface acoustic wave element has a pair of reflector electrode arrange | positioned in the position which pinches | interposes the said 1st thru | or 5th IDT electrode in the direction along the said propagation direction. the surface acoustic wave device. 請求項１乃至５のいずれか１項に記載の弾性表面波装置を有する、受信回路及び送信回路の少なくとも一方を備えた通信装置。 A communication apparatus comprising at least one of a reception circuit and a transmission circuit, comprising the surface acoustic wave device according to claim 1 .
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