JP5955095B2

JP5955095B2 - Elastic wave device

Info

Publication number: JP5955095B2
Application number: JP2012116192A
Authority: JP
Inventors: 池内　哲; 哲池内; 和紀西村
Original assignee: スカイワークス・パナソニックフィルターソリューションズジャパン株式会社
Priority date: 2012-05-22
Filing date: 2012-05-22
Publication date: 2016-07-20
Anticipated expiration: 2032-05-22
Also published as: JP2013243570A

Description

本発明は、主として移動体通信機器等においてフィルタまたはアンテナ共用器として使用される弾性波装置に関するものである。 The present invention relates to an acoustic wave device mainly used as a filter or an antenna duplexer in a mobile communication device or the like.

携帯電話の無線回路に用いられる弾性波装置は小型、低背かつ軽量であることに加え、所望の通過帯域の挿入損失が小さくかつ通過帯域外の減衰量が大きいことが求められる。挿入損失が小さい弾性波装置としては共振器を梯子型に接続した所謂ラダー型フィルタが知られている。 An elastic wave device used for a radio circuit of a cellular phone is required to have a small insertion loss in a desired pass band and a large attenuation outside the pass band, in addition to being small, low profile, and lightweight. As an acoustic wave device having a small insertion loss, a so-called ladder filter having a resonator connected in a ladder shape is known.

従来のラダー型フィルタを図１３（ａ）、（ｂ）に示す。図１３（ａ）は従来の弾性波装置１００の回路図、図１３（ｂ）は従来の弾性波装置１００の断面模式図である。図１３（ａ）、（ｂ）において、従来の弾性波装置１００は、弾性波素子を形成した圧電基板１９０を、内部に回路を有するセラミック基板１０５の上に実装し、封止体１０６で封止したものであり、セラミック基板１０５の表面には信号端子１１１、１１２と基準電位端子１８３、１８４を有する。圧電基板１９０の表面には、２つの信号端子１１１、１１２の間に接続される配線１６１を有し、配線１６１には、複数の直列腕共振器１２１、１２２、１２３、１２４、１２５が直列に接続される。配線１６１と基準電位端子１８３の間を接続する配線１６４を有し、配線１６４には、並列腕共振器１３１とインダクタ１７３が直列に接続される。配線１６１と基準電位端子１８４の間を複数の配線１６５が接続し、個々の配線１６５には、並列腕共振器１３２、１３３、１３４がそれぞれ直列に接続され、共通接続された後にインダクタ１７４を介して基準電位端子１８４に接続される。インダクタ１７３およびインダクタ１７４は、セラミック基板１０５の内部にらせん状の導体を形成して構成している。 A conventional ladder type filter is shown in FIGS. FIG. 13A is a circuit diagram of a conventional acoustic wave device 100, and FIG. 13B is a schematic cross-sectional view of the conventional acoustic wave device 100. FIG. 13 (a) and 13 (b), the conventional acoustic wave device 100 has a piezoelectric substrate 190 on which an acoustic wave element is formed mounted on a ceramic substrate 105 having a circuit therein and sealed with a sealing body 106. The ceramic substrate 105 has signal terminals 111 and 112 and reference potential terminals 183 and 184 on the surface thereof. The surface of the piezoelectric substrate 190 has a wiring 161 connected between the two signal terminals 111 and 112, and a plurality of series arm resonators 121, 122, 123, 124, and 125 are connected in series to the wiring 161. Connected. A wiring 164 connecting the wiring 161 and the reference potential terminal 183 is provided, and the parallel arm resonator 131 and the inductor 173 are connected in series to the wiring 164. A plurality of wirings 165 are connected between the wiring 161 and the reference potential terminal 184, and parallel arm resonators 132, 133, and 134 are connected in series to the individual wirings 165, respectively, and are connected in common and then passed through the inductor 174. To the reference potential terminal 184. The inductor 173 and the inductor 174 are configured by forming a spiral conductor inside the ceramic substrate 105.

このように、従来の弾性波装置１００は、並列腕共振器１３１にインダクタ１７３を直列に接続することにより、並列腕共振器１３１とインダクタ１７３との共振により、通過帯域外に減衰極を形成し、減衰量を確保していた。そして、基準電位端子１８３、１８４を複数個設け、並列腕共振器とインダクタと基準電位端子の直列接続を別個に複数個設けることにより、複数個の減衰極を形成し、帯域外の減衰を確保していた。 As described above, the conventional acoustic wave device 100 connects the parallel arm resonator 131 to the inductor 173 in series, thereby forming an attenuation pole outside the passband due to resonance between the parallel arm resonator 131 and the inductor 173. The amount of attenuation was secured. A plurality of reference potential terminals 183 and 184 are provided, and a plurality of series connection of a parallel arm resonator, an inductor, and a reference potential terminal are provided separately, thereby forming a plurality of attenuation poles and ensuring out-of-band attenuation. Was.

なお、この出願の発明に関する先行技術文献情報としては、例えば、特許文献１、特許文献２が知られている。 For example, Patent Document 1 and Patent Document 2 are known as prior art document information relating to the invention of this application.

国際公開第２００１／００５０３１号International Publication No. 2001/005031 特開２００４−７２５０号公報JP 2004-7250 A

しかしながら、前記従来の弾性波装置１００では、６ＧＨｚ以上の高い周波数に亘って広帯域に減衰量を確保するには、インダクタの数を増やすとともにインダクタンスを極めて大きくする必要があるため、弾性波装置１００の内部にこのような大きなインダクタを数多く形成することは困難であり、広帯域にわたる減衰量の確保が困難であった。 However, in the conventional acoustic wave device 100, in order to secure attenuation in a wide band over a high frequency of 6 GHz or more, it is necessary to increase the number of inductors and the inductance to be extremely large. It was difficult to form a large number of such large inductors inside, and it was difficult to secure attenuation over a wide band.

本発明は、通過帯域外おいて、広帯域にわたって良好な減衰量を確保することのできる弾性波装置を提供するものである。 The present invention provides an elastic wave device capable of securing a good attenuation over a wide band outside the pass band.

上記課題を解決するために、本願発明は、２つの信号端子の間に接続され、圧電基板の表面に形成された第１の配線と、前記第１の配線に直列に接続され、一端子対弾性波素子からなる直列腕共振器と、基準電位端子の１つに接続され、前記圧電基板の表面に形成された第１の基準電極と、前記第１の配線上に設けられた接続点と前記第１の基準電極との間に接続された第２の配線と、前記第２の配線に直列に接続され、一端子対弾性波素子からなる並列腕共振器とを備え、基準電位端子の１つに接続され、前記圧電基板の表面において前記第１の基準電極と電気的に直接接続されていない第２の基準電極を設け、前記第２の基準電極と前記接続点とを接続する第３の配線を設け、前記第３の配線に直列に第１の容量素子を接続した構成としたものである。 In order to solve the above-mentioned problems, the present invention provides a first wire connected between two signal terminals, formed on the surface of the piezoelectric substrate, and connected in series to the first wire. A series arm resonator composed of an acoustic wave element; a first reference electrode connected to one of the reference potential terminals; formed on the surface of the piezoelectric substrate; and a connection point provided on the first wiring; A second wiring connected between the first reference electrode and a parallel arm resonator connected in series to the second wiring and made up of a one-terminal pair acoustic wave element; A second reference electrode that is connected to one and is not electrically connected directly to the first reference electrode on the surface of the piezoelectric substrate, and that connects the second reference electrode and the connection point; 3 wirings, and the first capacitive element is connected in series to the third wiring. It is intended.

このような構成としたことで、通過帯域外おいて、広帯域にわたって良好な減衰量を確保することのできる弾性波装置を得ることができるという優れた効果を有する。 With such a configuration, there is an excellent effect that it is possible to obtain an elastic wave device that can secure a good attenuation over a wide band outside the pass band.

（ａ）本発明の実施の形態１の弾性波装置の回路図、（ｂ）同弾性波装置の断面模式図(A) Circuit diagram of elastic wave device according to embodiment 1 of the present invention, (b) Schematic cross-sectional view of the elastic wave device 同弾性波装置のパターン図Pattern of the elastic wave device 同弾性波装置の特性図Characteristics diagram of the elastic wave device 同弾性波装置の特性図Characteristics diagram of the elastic wave device 本発明の実施の形態１の他の弾性波装置の回路図Circuit diagram of another elastic wave device according to the first embodiment of the present invention 同弾性波装置の特性図Characteristics diagram of the elastic wave device 本発明の実施の形態２の弾性波装置の回路図Circuit diagram of elastic wave device of embodiment 2 of the present invention 同弾性波装置のパターン図Pattern of the elastic wave device 同弾性波装置の特性図Characteristics diagram of the elastic wave device 同弾性波装置の特性図Characteristics diagram of the elastic wave device 本発明の実施の形態３の弾性波装置の回路図Circuit diagram of elastic wave device of embodiment 3 of the present invention 同弾性波装置の特性図Characteristics diagram of the elastic wave device （ａ）従来の弾性波装置の回路図、（ｂ）同弾性波装置の断面模式図(A) Circuit diagram of a conventional acoustic wave device, (b) Schematic cross-sectional view of the acoustic wave device

以下、本発明の実施の形態における弾性波装置について図面を参照して説明する。 Hereinafter, an elastic wave device according to an embodiment of the present invention will be described with reference to the drawings.

（実施の形態１）
図１（ａ）は本発明の実施の形態１における弾性波装置１０１の回路図、図１（ｂ）は弾性波装置１０１の断面模式図、図２は弾性波装置１０１のパターン図である。図１（ａ）、（ｂ）、図２において、弾性波装置１０１は、圧電基板９０の表面に、励振空間１３を介して弾性波素子を封止する封止体１４を有し、この封止体１４の表面に信号端子１１、１２と基準電位端子８１、８２を有する。信号端子１１と信号端子１２は、それぞれ、弾性波装置１０１の入力端子と出力端子、または、出力端子と入力端子として用いられる。基準電位端子８１、８２はグランド端子として用いられ、２つの基準電位端子８１、８２は電気的に直接には接続されていない。圧電基板９０上には、第１の配線６１と第２の配線６２と第３の配線６３と第１の基準電極６４と第２の基準電極６５とを有する。第１の配線６１は、信号端子１１と信号端子１２との間を接続する配線である。第１の配線６１上には、一端子対弾性波素子からなる直列腕共振器２１、２２、２３、２４、２５を直列に接続する。第２の配線６２は、第１の配線６１の上の接続点９１、９２、９３、９４と第１の基準電極６４とを接続する複数の配線である。各第２の配線６２上には、それぞれ、一端子対弾性波素子からなる並列腕共振器３１、３２、３３、３４が直列に接続される。直列腕共振器２１、２２、２３、２４、２５および並列腕共振器３１、３２、３３、３４は、それぞれ、圧電基板９０上に形成された一端子対弾性波素子であり、一対の反射器の間に挟まれた１個のＩＤＴ（ＩｎｔｅｒＤｉｇｉｔａｌＴｒａｎｓｄｕｓｅｒ）からなる。第３の配線６３は、第１の配線６１の上の接続点９１、９２、９３、９４と第２の基準電極６５とを接続する複数の配線である。第３の配線６３上には、それぞれ、櫛型電極からなる容量素子４１、４２、４３、４４を直列に接続する。ここで、容量素子４１、４２、４３、４４は、各々の容量の合計が２．０５ｐＦになるように設計している。第１の基準電極６４は、封止体１４を貫通する導体からなるインダクタ７１を経由して基準電位端子８１に接続される。第２の基準電極６５は、封止体１４を貫通する導体からなるインダクタ７２を経由して基準電位端子８２に接続される。第１の基準電極６４と第２の基準電極６５は、それぞれ、圧電基板９０の互いに対向する端辺に配置し、互いに電気的に直接には接続しない。インダクタ７１およびインダクタ７２のインダクタンスは、０．１０ｎＨ程度である。 (Embodiment 1)
1A is a circuit diagram of an acoustic wave device 101 according to Embodiment 1 of the present invention, FIG. 1B is a schematic cross-sectional view of the acoustic wave device 101, and FIG. 2 is a pattern diagram of the acoustic wave device 101. 1A, 1 </ b> B, and 2, an acoustic wave device 101 includes a sealing body 14 that seals an acoustic wave element through an excitation space 13 on the surface of a piezoelectric substrate 90. Signal terminals 11 and 12 and reference potential terminals 81 and 82 are provided on the surface of the stopper 14. The signal terminal 11 and the signal terminal 12 are used as an input terminal and an output terminal of the acoustic wave device 101 or as an output terminal and an input terminal, respectively. The reference potential terminals 81 and 82 are used as ground terminals, and the two reference potential terminals 81 and 82 are not electrically connected directly. On the piezoelectric substrate 90, a first wiring 61, a second wiring 62, a third wiring 63, a first reference electrode 64, and a second reference electrode 65 are provided. The first wiring 61 is a wiring that connects between the signal terminal 11 and the signal terminal 12. On the first wiring 61, series arm resonators 21, 22, 23, 24, and 25 composed of one-terminal-pair acoustic wave elements are connected in series. The second wiring 62 is a plurality of wirings that connect the connection points 91, 92, 93, 94 on the first wiring 61 and the first reference electrode 64. On each second wiring 62, parallel arm resonators 31, 32, 33, and 34 each consisting of a one-terminal pair acoustic wave element are connected in series. The series arm resonators 21, 22, 23, 24, 25 and the parallel arm resonators 31, 32, 33, 34 are respectively one-terminal-pair elastic wave elements formed on the piezoelectric substrate 90, and a pair of reflectors It consists of one IDT (Inter Digital Transducer) sandwiched between the two. The third wiring 63 is a plurality of wirings that connect the connection points 91, 92, 93, 94 on the first wiring 61 and the second reference electrode 65. On the third wiring 63, capacitive elements 41, 42, 43, and 44 each including a comb-shaped electrode are connected in series. Here, the capacitive elements 41, 42, 43, and 44 are designed so that the total of the respective capacitances is 2.05 pF. The first reference electrode 64 is connected to the reference potential terminal 81 via an inductor 71 made of a conductor that penetrates the sealing body 14. The second reference electrode 65 is connected to the reference potential terminal 82 via an inductor 72 made of a conductor that penetrates the sealing body 14. The first reference electrode 64 and the second reference electrode 65 are disposed on opposite sides of the piezoelectric substrate 90, respectively, and are not electrically connected directly to each other. The inductances of the inductor 71 and the inductor 72 are about 0.10 nH.

以上のように構成された弾性波装置１０１は、直列腕共振器２１、２２、２３、２４、２５と並列腕共振器３１、３２、３３、３４によりラダー型フィルタを構成し、７０４ＭＨｚ〜７１６ＭＨｚの送信帯域と７３４ＭＨｚ〜７４６ＭＨｚの受信帯域を有するＢａｎｄ１７の無線通信装置における共用器の送信フィルタとして設計したものであり、内蔵する圧電基板９０と同等レベルの占有面積を有する極めて小型で低背のウエハレベル構造を実現したものである。 The elastic wave device 101 configured as described above includes a ladder-type filter including the series arm resonators 21, 22, 23, 24, and 25 and the parallel arm resonators 31, 32, 33, and 34, and operates at 704 MHz to 716 MHz. Designed as a transmission filter for a duplexer in a Band 17 wireless communication apparatus having a transmission band and a reception band of 734 MHz to 746 MHz, and an extremely small and low-profile wafer level having an occupation area equivalent to that of the built-in piezoelectric substrate 90 The structure is realized.

本発明の実施の形態１における弾性波装置１０１の電気特性を図３、図４に示す。図３、図４において、横軸は周波数、縦軸は減衰量であり、本発明の実施の形態１における弾性波装置１０１の電気特性Ａを実線で示し、比較例の電気特性Ｅを破線で示す。図４において、通過帯域Ｓは送信帯域である７０４ＭＨｚ〜７１６ＭＨｚであり、７３４ＭＨｚ〜７４６ＭＨｚの受信帯域Ｔは、通過帯域Ｓの高域側の帯域外にある。 The electrical characteristics of the acoustic wave device 101 according to the first embodiment of the present invention are shown in FIGS. 3 and 4, the horizontal axis represents frequency, and the vertical axis represents attenuation. The electrical characteristic A of the acoustic wave device 101 according to the first embodiment of the present invention is indicated by a solid line, and the electrical characteristic E of the comparative example is indicated by a broken line. Show. In FIG. 4, the pass band S is 704 MHz to 716 MHz, which is a transmission band, and the reception band T of 734 MHz to 746 MHz is outside the band on the high frequency side of the pass band S.

図３、図４における比較例は、図１３（ａ）、（ｂ）に示した従来の弾性波装置１００において、直列腕共振器１２１、１２２、１２３、１２４、１２５と並列腕共振器１３１、１３２、１３３、１３４のそれぞれを本発明の実施の形態１における弾性波装置１０１の直列腕共振器２１、２２、２３、２４、２５と並列腕共振器３１、３２、３３、３４のそれぞれと同じ設計にして構成した７０４ＭＨｚ〜７１６ＭＨｚの送信帯域を有するＢａｎｄ１７の送信フィルタである。 3 and FIG. 4 show a series of arm resonators 121, 122, 123, 124, 125 and a parallel arm resonator 131 in the conventional acoustic wave device 100 shown in FIGS. 132, 133, and 134 are the same as the series arm resonators 21, 22, 23, 24, and 25 and the parallel arm resonators 31, 32, 33, and 34 of the acoustic wave device 101 according to the first embodiment of the present invention. This is a Band 17 transmission filter having a transmission band of 704 MHz to 716 MHz designed and configured.

図３より、本発明の実施の形態１における弾性波装置１０１の電気特性Ａは、比較例の電気特性Ｅと比較して、１．３ＧＨｚより高い周波数領域において本発明の減衰特性が格段に優れていることがわかる。 As shown in FIG. 3, the electrical characteristic A of the acoustic wave device 101 according to the first embodiment of the present invention is significantly superior in the attenuation characteristic of the present invention in a frequency region higher than 1.3 GHz as compared with the electrical characteristic E of the comparative example. You can see that

比較例の減衰特性は、１．２ＧＨｚ付近の減衰極Ｅ１と３ＧＨｚ付近の減衰極Ｅ２が形成されているが、減衰極Ｅ１、Ｅ２間の幅が比較的狭く、３ＧＨｚ付近からより高い周波数に行くに従って急激に減衰量が悪化している。 In the attenuation characteristic of the comparative example, an attenuation pole E1 near 1.2 GHz and an attenuation pole E2 near 3 GHz are formed, but the width between the attenuation poles E1 and E2 is relatively narrow, and the frequency goes from around 3 GHz to a higher frequency. As shown, the amount of attenuation suddenly deteriorates.

本発明の実施の形態１の弾性波装置１０１は、並列腕共振器３１、３２、３３、３４のそれぞれの静電容量の総和とインダクタ７１による直列共振による２．３ＧＨｚ近辺の減衰極Ａ１が比較的広帯域かつ高減衰である。また図３より確認できるように高周波数領域（２．３ＧＨｚ〜８．５ＧＨｚ）において、良好な減衰特性が得られていることが判る。 The elastic wave device 101 according to the first embodiment of the present invention compares the total capacitance of the parallel arm resonators 31, 32, 33, and 34 with the attenuation pole A 1 near 2.3 GHz due to series resonance by the inductor 71. Wide bandwidth and high attenuation. Further, as can be seen from FIG. 3, it can be seen that good attenuation characteristics are obtained in the high frequency region (2.3 GHz to 8.5 GHz).

図４からは、本発明の実施の形態１の弾性波装置１０１の電気特性Ａは、比較例の電気特性Ｅと比べて、通過帯域Ｓの高域側近傍の減衰量を良好に確保することができ、特に７３４ＭＨｚ〜７４６ＭＨｚの受信帯域Ｔの減衰特性が優れていることがわかる。 From FIG. 4, the electrical characteristic A of the elastic wave device 101 according to the first embodiment of the present invention ensures a good attenuation in the vicinity of the high band side of the pass band S compared to the electrical characteristic E of the comparative example. In particular, it can be seen that the attenuation characteristic of the reception band T of 734 MHz to 746 MHz is excellent.

以上のように、本発明の実施の形態１の弾性波装置１０１は、容量素子４１、４２、４３、４４とインダクタ７２を直列接続することでＬＣの直列共振によるなだらかな減衰極をＧＨｚ以上の高周波領域に形成することができるため、広帯域にわたって良好な減衰特性を得ることができた。 As described above, the elastic wave device 101 according to the first embodiment of the present invention connects the capacitive elements 41, 42, 43, 44 and the inductor 72 in series so that the gentle attenuation pole due to the LC series resonance is equal to or higher than GHz. Since it can be formed in a high frequency region, a good attenuation characteristic can be obtained over a wide band.

すなわち、容量素子４１、４２、４３、４４の各々の容量の合計を２．０５ｐＦとし、インダクタ７２のインダクタンスを０．１０ｎＨとしたことにより、減衰極Ａ１を１１ＧＨｚ近辺に形成することができ、非常に高い周波数領域まで良好な減衰特性を得ることができた。そして、容量素子４１、４２、４３、４４の容量値の合計とインダクタ７２のインダクタンスを適切に設定することにより、減衰極の位置を調整することができる。 That is, by setting the total capacitance of the capacitive elements 41, 42, 43, and 44 to 2.05 pF and the inductance of the inductor 72 to 0.10 nH, the attenuation pole A1 can be formed in the vicinity of 11 GHz. Good attenuation characteristics were obtained up to a high frequency range. The position of the attenuation pole can be adjusted by appropriately setting the sum of the capacitance values of the capacitive elements 41, 42, 43, and 44 and the inductance of the inductor 72.

そして、本発明の実施の形態１の弾性波装置１０１は、容量素子４１、４２、４３、４４を圧電基板９０上に形成し、圧電基板９０上から基準電位端子８１、８２までを接続する導体レベルの非常に小さなインダクタンスでもって広帯域にわたる良好な減衰特性を得ることができるため、別途、インダクタを形成するための多層セラミック基板のような大掛かりな構造を必要とせずに、減衰特性の良好な弾性波装置を実現できるものであり、弾性波装置の小型化を実現できるものである。特に、ウエハレベルのように、セラミック基板等を有さない極めて小型の弾性波装置において良好な減衰特性を可能にする。 In the elastic wave device 101 according to the first embodiment of the present invention, the capacitive elements 41, 42, 43, and 44 are formed on the piezoelectric substrate 90, and the conductors connecting the piezoelectric substrate 90 to the reference potential terminals 81 and 82 are connected. Good damping characteristics over a wide band can be obtained with a very small inductance level, so there is no need for a large structure such as a multilayer ceramic substrate for forming an inductor separately. The wave device can be realized, and the elastic wave device can be miniaturized. In particular, it is possible to achieve good damping characteristics in an extremely small elastic wave device that does not have a ceramic substrate or the like as at the wafer level.

さらに、本発明の実施の形態１の弾性波装置１０１は、複数の並列腕共振器３１、３２、３３、３４を電気的に共通接続してインダクタ７１を介して基準電位端子８１に接続したことで、通過帯域の高域側近傍の減衰量を良好に確保することができ、特に７３４ＭＨｚ〜７４６ＭＨｚの受信帯域の減衰量を良好にすることができた。 Furthermore, in the elastic wave device 101 according to the first embodiment of the present invention, the plurality of parallel arm resonators 31, 32, 33, and 34 are electrically connected in common and connected to the reference potential terminal 81 via the inductor 71. Thus, it was possible to secure a good attenuation in the vicinity of the high band side of the pass band, and in particular, it was possible to improve the attenuation in the reception band of 734 MHz to 746 MHz.

さらに、本発明の実施の形態１の弾性波装置１０１は、基準電位端子８１と基準電位端子８２を電気的に直接に接続しない構成にしたことで、容量素子４１、４２、４３、４４をローパスフィルタとして機能させることができるとともに、第１の基準電極６４から第２の基準電極６５への信号の回り込みを防止することができるため、減衰量を効果的に確保することができた。 Furthermore, the acoustic wave device 101 according to the first embodiment of the present invention has a configuration in which the reference potential terminal 81 and the reference potential terminal 82 are not directly electrically connected, so that the capacitive elements 41, 42, 43, and 44 are low-pass. In addition to being able to function as a filter, it is possible to prevent the signal from wrapping around from the first reference electrode 64 to the second reference electrode 65, so that the attenuation amount can be effectively ensured.

また、本発明の実施の形態１の弾性波装置１０１の構成は、回路的に見ると容量素子４１は並列腕共振器３１と実質的に並列接続されており、並列腕共振器３１の反共振周波数を低周波側にシフトさせる作用を有するため、並列腕共振器３１の共振周波数と反共振周波数の周波数差が実質的に小さくなる。同様に容量素子４２は並列腕共振器３２と並列接続されており、容量素子４３は並列腕共振器３３と並列接続されており、容量素子４４は並列腕共振器３４と並列接続されており、各々の共振器の共振周波数と反共振周波数の周波数差が実質的に小さくなる。したがって、より狭帯域のフィルタを作成することが可能であり、通過帯域が７０４ＭＨｚ〜７１６ＭＨｚであるＢａｎｄ１７の送信フィルタのように通過帯域幅／中心周波数で定義される比帯域が１．６９％と比較的狭い帯域幅のフィルタを作成した場合、通過帯域近傍の減衰特性の良好なフィルタ特性が得られる。 Further, in the configuration of the acoustic wave device 101 according to the first embodiment of the present invention, the capacitance element 41 is substantially connected in parallel with the parallel arm resonator 31 in terms of a circuit, and the antiresonance of the parallel arm resonator 31 is achieved. Since it has the effect of shifting the frequency to the low frequency side, the frequency difference between the resonance frequency and antiresonance frequency of the parallel arm resonator 31 is substantially reduced. Similarly, the capacitive element 42 is connected in parallel with the parallel arm resonator 32, the capacitive element 43 is connected in parallel with the parallel arm resonator 33, and the capacitive element 44 is connected in parallel with the parallel arm resonator 34, The frequency difference between the resonance frequency and antiresonance frequency of each resonator is substantially reduced. Therefore, it is possible to create a narrower band filter, and the ratio band defined by the pass band width / center frequency is 1.69% compared to the Band 17 transmission filter whose pass band is 704 MHz to 716 MHz. When a filter with a narrow bandwidth is created, a filter characteristic having a good attenuation characteristic in the vicinity of the pass band can be obtained.

また、本発明の実施の形態１の弾性波装置１０１は、第１の基準電極６４と第２の基準電極６５を、それぞれ、圧電基板９０の互いに対向する端辺に配置し、互いに電気的に直接には接続しないように構成することで、電磁界結合や、グランド配線を介した信号の伝達を抑制でき、良好な減衰特性が得られる。圧電基板９０の表面上以外の部分であれば基準電位端子８１と基準電位端子８２が電気的に接続されていても本発明の効果を有するが、基準電位端子８１と基準電位端子８２が電気的に接続しない構成がより効果が大きい。 In the elastic wave device 101 according to the first embodiment of the present invention, the first reference electrode 64 and the second reference electrode 65 are arranged on opposite sides of the piezoelectric substrate 90, respectively, and electrically connected to each other. By configuring so as not to be directly connected, it is possible to suppress electromagnetic field coupling and signal transmission through the ground wiring, and to obtain good attenuation characteristics. Even if the reference potential terminal 81 and the reference potential terminal 82 are electrically connected to any part other than the surface of the piezoelectric substrate 90, the effect of the present invention is obtained. However, the reference potential terminal 81 and the reference potential terminal 82 are electrically connected. A configuration that does not connect to the device is more effective.

なお、本発明の実施の形態１における弾性波装置１０１は、７０４ＭＨｚ〜７１６ＭＨｚの送信帯域を有するＢａｎｄ１７の無線通信装置における送信フィルタであるが、本願発明は、他の通過帯域を有する高周波フィルタに適用してもよく、高周波フィルタを備えたデュプレクサのような装置に適用しても同様に効果を有し、１つの圧電基板の上に受信フィルタとともに設置する送信フィルタに適用しても良く、受信フィルタに適用しても良い。 The elastic wave device 101 according to the first embodiment of the present invention is a transmission filter in a Band 17 wireless communication device having a transmission band of 704 MHz to 716 MHz, but the present invention is applied to a high frequency filter having another pass band. Even if applied to a device such as a duplexer equipped with a high frequency filter, the same effect is obtained, and it may be applied to a transmission filter installed together with a reception filter on one piezoelectric substrate. You may apply to.

しかし、本願発明は、使用しようとする周波数帯域から大きく離れた周波数帯域における不要信号を広帯域に渡って抑制することができるため、特に、送信フィルタとして使用することにより、他の周波数帯域を使用する無線通信機器に対する妨害信号を抑制することができるという効果を有する。 However, according to the present invention, unnecessary signals in a frequency band far away from the frequency band to be used can be suppressed over a wide band. In particular, by using as a transmission filter, another frequency band is used. It has the effect that the interference signal with respect to a radio | wireless communication apparatus can be suppressed.

また、本発明の弾性波装置１０１では、全ての並列腕共振器に対して並列接続された容量素子を設けたが、少なくとも１つの並列腕共振器に対して並列接続された容量素子を有せば本願発明の効果を有する。しかし、十分な減衰量を確保するためには、できるだけ多くの並列腕共振器に容量素子を並列接続することが好ましく、全ての並列腕共振器に並列接続された容量素子を設けることがより好ましい。 In the acoustic wave device 101 of the present invention, the capacitive element connected in parallel to all the parallel arm resonators is provided, but the capacitive element connected in parallel to at least one parallel arm resonator should be provided. If it has the effect of this invention. However, in order to ensure a sufficient amount of attenuation, it is preferable to connect capacitive elements to as many parallel arm resonators as possible, and it is more preferable to provide capacitive elements connected in parallel to all the parallel arm resonators. .

また、本発明の実施の形態１の弾性波装置１０１では、インダクタ７１およびインダクタ７２は、封止体１４を貫通する導体により構成したが、封止体１４の中にスパイラル状やミアンダ状の配線を設けて使用しても良いものであり、屈曲部を有する導体により構成しても良い。 Further, in the elastic wave device 101 according to the first embodiment of the present invention, the inductor 71 and the inductor 72 are configured by conductors that penetrate the sealing body 14, but a spiral or meander-like wiring is formed in the sealing body 14. May be used, and may be formed of a conductor having a bent portion.

また、本発明の実施の形態１の弾性波装置１０１では、全ての並列腕共振器３１、３２、３３、３４を１つの基準電極６４に接続して第１の基準電位端子８１に接続したが、並列腕共振器に接続する基準電極を複数に分けても良い。 In the elastic wave device 101 according to the first embodiment of the present invention, all the parallel arm resonators 31, 32, 33, and 34 are connected to one reference electrode 64 and connected to the first reference potential terminal 81. The reference electrode connected to the parallel arm resonator may be divided into a plurality of parts.

図５は、本発明の実施の形態１の他の弾性波装置１０２の回路図であり、図１、図２で示した本発明の実施の形態１における弾性波装置１０１と同じ構成要素については同一番号を付しており、その説明は省略する。図５に示す実施の形態１の他の弾性波装置１０２が、本発明の実施の形態１の弾性波装置１０１と異なる点は、並列腕共振器３１、３２、３３、３４に接続される基準電極とインダクタと基準電位端子を２つに分けたことである。すなわち、並列腕共振器３１は、基準電極６６とインダクタ７３を介して基準電位端子８３に接続し、並列腕共振器３２、３３、３４は、基準電極６７とインダクタ７４を介して基準電位端子８４に接続したものである。 FIG. 5 is a circuit diagram of another elastic wave device 102 according to the first embodiment of the present invention. The same components as those of the elastic wave device 101 according to the first embodiment of the present invention shown in FIGS. The same number is given and the explanation is omitted. The other elastic wave device 102 of the first embodiment shown in FIG. 5 is different from the elastic wave device 101 of the first embodiment of the present invention in that the reference connected to the parallel arm resonators 31, 32, 33, and 34 is used. That is, the electrode, the inductor, and the reference potential terminal are divided into two. That is, the parallel arm resonator 31 is connected to the reference potential terminal 83 via the reference electrode 66 and the inductor 73, and the parallel arm resonators 32, 33, and 34 are connected to the reference potential terminal 84 via the reference electrode 67 and the inductor 74. Is connected to.

図５に示す実施の形態１の他の弾性波装置１０２の電気特性を図６に示す。 FIG. 6 shows the electrical characteristics of another elastic wave device 102 of the first embodiment shown in FIG.

図６において、横軸は周波数、縦軸は減衰量であり、本発明の実施の形態１における他の弾性波装置１０２の電気特性Ｂを一点破線で示し、比較例の電気特性Ｅを破線で示し、本発明の実施の形態１における弾性波装置１０１の電気特性Ａを実線で示す。 In FIG. 6, the horizontal axis represents frequency, and the vertical axis represents attenuation. The electric characteristic B of another elastic wave device 102 according to Embodiment 1 of the present invention is indicated by a one-dot broken line, and the electric characteristic E of the comparative example is indicated by a broken line. The electrical characteristic A of the acoustic wave device 101 according to the first embodiment of the present invention is indicated by a solid line.

図６において、通過帯域Ｓである送信帯域は７０４ＭＨｚ〜７１６ＭＨｚであり、通過帯域外である受信帯域Ｔは７３４ＭＨｚ〜７４６ＭＨｚである。 In FIG. 6, the transmission band that is the pass band S is 704 MHz to 716 MHz, and the reception band T that is outside the pass band is 734 MHz to 746 MHz.

このような構成とすることで、実施の形態１の他の弾性波装置１０２は通過帯域低域側の減衰特性を改善することができた。 By adopting such a configuration, the other acoustic wave device 102 of the first embodiment was able to improve the attenuation characteristics on the low pass band side.

（実施の形態２）
図７は本発明の実施の形態２における弾性波装置１０３を示す回路図、図８は同弾性波装置１０３のパターン図であり、図１、図２で示した本発明の実施の形態１における弾性波装置１０１と同じ構成要素については同一番号を付しており、その説明は省略する。 (Embodiment 2)
FIG. 7 is a circuit diagram showing the acoustic wave device 103 according to the second embodiment of the present invention, and FIG. 8 is a pattern diagram of the acoustic wave device 103 according to the first embodiment of the present invention shown in FIGS. The same components as those of the elastic wave device 101 are denoted by the same reference numerals, and the description thereof is omitted.

本発明の実施の形態２おける弾性波装置１０３が、本発明の実施の形態１における弾性波装置１０１と異なる点は、並列腕共振器３１、３２、３３、３４に並列に容量素子４５、４６、４７、４８を接続するとともに、第３の配線６３に接続した容量素子４１、４２、４３、４４の替わりに、第３の配線６３に静電容量の異なる容量素子５１、５２、５３、５４を接続したことである。 The elastic wave device 103 according to the second embodiment of the present invention is different from the elastic wave device 101 according to the first embodiment of the present invention in that the capacitive elements 45 and 46 are parallel to the parallel arm resonators 31, 32, 33 and 34. , 47, and 48, and instead of the capacitive elements 41, 42, 43, and 44 connected to the third wiring 63, capacitive elements 51, 52, 53, and 54 having different capacitances are connected to the third wiring 63. Is connected.

なお、本発明の実施の形態２の弾性波装置１０３における、直列腕共振器２１、２２、２３、２４、２５と、並列腕共振器３１、３２、３３、３４の各設計数値は、本発明の実施の形態１の弾性波装置１０１のものと同じ構成のものである。 In the elastic wave device 103 according to the second embodiment of the present invention, the design numerical values of the series arm resonators 21, 22, 23, 24, and 25 and the parallel arm resonators 31, 32, 33, and 34 are as follows. The configuration is the same as that of the elastic wave device 101 of the first embodiment.

そして、実施の形態２の弾性波装置１０３における容量素子５１の容量と容量素子４５の容量の合計を実施の形態１の弾性波装置１０１における容量素子４１の容量と等しく設計し、実施の形態２の弾性波装置１０３における容量素子５２の容量と容量素子４６の容量の合計を実施の形態１の弾性波装置１０１における容量素子４２の容量と等しく設計し、実施の形態２の弾性波装置１０３における容量素子５３の容量と容量素子４７の容量の合計を実施の形態１の弾性波装置１０１における容量素子４３の容量と等しく設計し、実施の形態２の弾性波装置１０３における容量素子５４の容量と容量素子４８の容量の合計を実施の形態１の弾性波装置１０１における容量素子４４の容量と等しく設計した。 Then, the total of the capacitance of the capacitive element 51 and the capacitance of the capacitive element 45 in the acoustic wave device 103 according to the second embodiment is designed to be equal to the capacitance of the capacitive element 41 in the acoustic wave device 101 according to the first embodiment. The total of the capacitance of the capacitive element 52 and the capacitance of the capacitive element 46 in the elastic wave device 103 is designed to be equal to the capacitance of the capacitive element 42 in the elastic wave device 101 of the first embodiment, and in the elastic wave device 103 of the second embodiment. The sum of the capacitance of the capacitive element 53 and the capacitance of the capacitive element 47 is designed to be equal to the capacitance of the capacitive element 43 in the acoustic wave device 101 of the first embodiment, and the capacitance of the capacitive element 54 in the acoustic wave device 103 of the second embodiment is The total capacity of the capacitive element 48 is designed to be equal to the capacity of the capacitive element 44 in the acoustic wave device 101 of the first embodiment.

本発明の実施の形態２においては、例えば並列腕共振器３１を例に説明すると、回路的に見て容量素子５１と容量素子４５は、ともに並列腕共振器３１に並列接続されており、容量素子５１と容量素子４５の容量の合計を一定にした条件下で、容量素子５１の容量と容量素子４５の容量の比率を適宜設定することにより、通過帯域幅などの特性に影響を与えることなく、高周波領域の減衰特性が改善できる。他の並列腕共振器３２、３３、３４についても同様に機能するため、実施の形態１と同じ通過帯域特性を保った状態で、減衰特性を改善でき、減衰特性の設計自由度が向上する。 In Embodiment 2 of the present invention, for example, the parallel arm resonator 31 will be described as an example. The capacitive element 51 and the capacitive element 45 are both connected in parallel to the parallel arm resonator 31 in terms of a circuit, and the capacitance By appropriately setting the ratio of the capacitance of the capacitive element 51 and the capacitance of the capacitive element 45 under the condition that the total capacitance of the element 51 and the capacitive element 45 is constant, the characteristics such as the pass bandwidth are not affected. The attenuation characteristic in the high frequency region can be improved. Since the other parallel arm resonators 32, 33, and 34 function in the same manner, the attenuation characteristic can be improved while maintaining the same passband characteristic as in the first embodiment, and the degree of freedom in designing the attenuation characteristic is improved.

次に、本発明の実施の形態２における弾性波装置１０３の電気特性を図９、図１０に示す。 Next, the electrical characteristics of the acoustic wave device 103 according to Embodiment 2 of the present invention are shown in FIGS.

図９、図１０において、横軸は周波数、縦軸は減衰量であり、本発明の実施の形態２における弾性波装置１０３の電気特性Ｃを実線で示し、本発明の実施の形態１における弾性波装置１０１の電気特性Ａを二点破線で示し、実施の形態１で説明した比較例の電気特性Ｅを破線で示す。図９、図１０において、通過帯域Ｓは送信帯域である７０４ＭＨｚ〜７１６ＭＨｚであり、７３４ＭＨｚ〜７４６ＭＨｚの受信帯域Ｔは、通過帯域Ｓの高域側の帯域外にある。 9 and 10, the horizontal axis represents frequency and the vertical axis represents attenuation, and the electric characteristic C of the acoustic wave device 103 according to the second embodiment of the present invention is indicated by a solid line, and the elasticity according to the first embodiment of the present invention is illustrated. The electric characteristic A of the wave device 101 is indicated by a two-dot broken line, and the electric characteristic E of the comparative example described in the first embodiment is indicated by a broken line. 9 and 10, the pass band S is 704 MHz to 716 MHz, which is a transmission band, and the reception band T of 734 MHz to 746 MHz is outside the high band side of the pass band S.

図９および図１０に示すように、本発明の実施の形態２の弾性波装置１０３の電気特性Ｃは、１．４ＧＨｚ〜３．７ＧＨｚの領域で２つの減衰極Ｃ１、Ｃ２を有し、実施の形態１の弾性波装置１０１の電気特性Ａと異なる位置に２つの減衰極を設けることができた。このように本発明の実施の形態２の弾性波装置１０３は、通過帯域特性に影響を与えることなく減衰極を追加するとともに所望の周波数に設定することが可能になり、良好な減衰特性を実現できる。 As shown in FIGS. 9 and 10, the electrical characteristic C of the elastic wave device 103 according to the second embodiment of the present invention has two attenuation poles C1 and C2 in the region of 1.4 GHz to 3.7 GHz. It was possible to provide two attenuation poles at positions different from the electrical characteristics A of the elastic wave device 101 of the first embodiment. As described above, the elastic wave device 103 according to the second embodiment of the present invention can add an attenuation pole without affecting the passband characteristics and can set a desired frequency, thereby realizing a good attenuation characteristic. it can.

なお、本発明の実施の形態２における弾性波装置１０３では、全ての並列腕共振器に回路的に見て２つの容量素子が接続された例を示したが、全ての並列腕共振器に２つの容量素子が接続する必要はなく、並列腕共振器と容量素子が回路的に並列接続となっていない並列腕共振器や並列腕共振器に１つの容量素子が接続される並列腕共振器を有してもよい。 In the elastic wave device 103 according to the second embodiment of the present invention, an example is shown in which two capacitive elements are connected to all parallel arm resonators in terms of a circuit. There is no need to connect two capacitive elements, a parallel arm resonator in which the parallel arm resonator and the capacitive element are not connected in parallel in a circuit, or a parallel arm resonator in which one capacitive element is connected to the parallel arm resonator. You may have.

（実施の形態３）
図１１は本発明の実施の形態３における弾性波装置１０４を示す回路図であり、図７、図８で示した本発明の実施の形態２における弾性波装置１０３と同じ構成要素については同一番号を付しており、その説明は省略する。 (Embodiment 3)
FIG. 11 is a circuit diagram showing acoustic wave device 104 according to Embodiment 3 of the present invention. The same components as those of acoustic wave device 103 according to Embodiment 2 of the present invention shown in FIGS. The description is omitted.

本発明の実施の形態３における弾性波装置１０４が、本発明の実施の形態２における弾性波装置１０３と異なる点は、直列腕共振器２１、２２、２３、２４、２５の中で、信号端子１１に最も近い直列腕共振器２１に並列に容量素子４９を設けるとともに、信号端子１２に最も近い直列腕共振器２５に並列に容量素子５０を設けたことである。 The elastic wave device 104 according to the third embodiment of the present invention is different from the elastic wave device 103 according to the second embodiment of the present invention in the series arm resonators 21, 22, 23, 24, and 25, with signal terminals. The capacitive element 49 is provided in parallel to the series arm resonator 21 closest to 11, and the capacitive element 50 is provided in parallel to the series arm resonator 25 closest to the signal terminal 12.

なお、本発明の実施の形態３の弾性波装置１０４における、直列腕共振器２１、２２、２３、２４、２５と、並列腕共振器３１、３２、３３、３４と、容量素子５１、５２、５３、５４、４５、４６、４７、４８の各設計数値は、本発明の実施の形態２の弾性波装置１０３におけるものと同じである。 In the elastic wave device 104 according to the third embodiment of the present invention, the series arm resonators 21, 22, 23, 24, 25, the parallel arm resonators 31, 32, 33, 34, and the capacitive elements 51, 52, The design values of 53, 54, 45, 46, 47, and 48 are the same as those in the acoustic wave device 103 according to the second embodiment of the present invention.

本発明の実施の形態３における弾性波装置１０４の電気特性を図１２に示す。図１２において、横軸は周波数、縦軸は減衰量であり、本発明の実施の形態３における弾性波装置１０４の電気特性Ｄを実線で示し、本発明の実施の形態１における弾性波装置１０１の電気特性Ａを一点破線で示し、本発明の実施の形態１で説明した比較例の電気特性Ｅを破線で示す。図１２において、通過帯域Ｓは送信帯域である７０４ＭＨｚ〜７１６ＭＨｚであり、７３４ＭＨｚ〜７４６ＭＨｚの受信帯域Ｔは、通過帯域Ｓの高域側の帯域外にある。
FIG. 12 shows the electrical characteristics of the acoustic wave device 104 according to Embodiment 3 of the present invention. 12, the horizontal axis represents frequency and the vertical axis is attenuation, showing the electrical characteristics D of the acoustic wave device 104 according to the third embodiment of the present invention in solid lines, acoustic wave device according to the first embodiment of the present invention An electric characteristic A of 101 is indicated by a one-dot broken line, and an electric characteristic E of the comparative example described in the first embodiment of the present invention is indicated by a broken line. In FIG. 12, the pass band S is 704 MHz to 716 MHz, which is a transmission band, and the reception band T of 734 MHz to 746 MHz is outside the high band side band of the pass band S.

図１２に示すように、本発明の実施の形態３における弾性波装置１０４の電気特性Ｄは、本発明の実施の形態１における弾性波装置１０１の電気特性Ａに近い特性を有する領域もあるが、通過帯域Ｓの高域部において挿入損失をより低減することができた。
As shown in FIG. 12, the electrical characteristics D of the acoustic wave device 104 according to the third embodiment of the present invention, there is also a region having characteristics similar to the electrical characteristics A of the acoustic wave device 101 according to the first embodiment of the present invention However, the insertion loss can be further reduced in the high band part of the pass band S.

以上のように、本発明の実施の形態３における弾性波装置１０４は、信号端子１１、１２に最も近い直列腕共振器２１、２５に並列接続された容量素子４９、５０を設けることで、狭帯域なフィルタを形成した際のインピーダンスマッチングがよくなり、インピーダンスミスマッチによる損失が小さくなり、低損失な弾性波装置が得られる。 As described above, the elastic wave device 104 according to the third embodiment of the present invention is narrow by providing the capacitive elements 49 and 50 connected in parallel to the series arm resonators 21 and 25 closest to the signal terminals 11 and 12. Impedance matching is improved when a band-pass filter is formed, loss due to impedance mismatch is reduced, and a low-loss acoustic wave device can be obtained.

なお、実施の形態１、実施の形態２および実施の形態３の弾性波装置に用いられる容量素子は必ずしも櫛電極により構成形成される必要はなく、２枚の平行平板で誘電体を挟むように形成されてもよい。 Note that the capacitive element used in the elastic wave devices of the first, second, and third embodiments is not necessarily formed by the comb electrode, and the dielectric is sandwiched between two parallel plates. It may be formed.

また、実施の形態１、実施の形態２および実施の形態３の弾性波装置に用いられる弾性波素子は弾性表面波、境界波、バルク波の内、いずれかを用いたものでもよい。 The elastic wave element used in the elastic wave devices of the first embodiment, the second embodiment, and the third embodiment may use any one of a surface acoustic wave, a boundary wave, and a bulk wave.

本発明に係る弾性波装置は、低挿入損失かつ高周波数領域においても良好な通過帯域外減衰量を有するという優れた効果を奏するものであり、主として移動体通信機器にフィルタやアンテナ共用器として用いられる弾性波装置において有用となるものである。 The elastic wave device according to the present invention has an excellent effect of having a low insertion loss and a good out-of-pass attenuation even in a high frequency region, and is mainly used as a filter or an antenna duplexer in a mobile communication device. This is useful in an elastic wave device.

１１、１２信号端子
２１、２２、２３、２４、２５直列腕共振器
３１、３２、３３、３４並列腕共振器
４１、４２、４３、４４、４５、４６、４７、４８、４９、５０、５１、５２、５３、５４容量素子
６１第１の配線
６２第２の配線
６３第３の配線
６４第１の基準電極
６５第２の基準電極
７１、７２、７３、７４インダクタ
８１、８２、８３、８４基準電位端子
９０圧電基板
９１、９２、９３、９４接続点
１０１、１０２、１０３、１０４弾性波装置 11, 12 Signal terminal 21, 22, 23, 24, 25 Series arm resonator 31, 32, 33, 34 Parallel arm resonator 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51 , 52, 53, 54 Capacitor element 61 First wiring 62 Second wiring 63 Third wiring 64 First reference electrode 65 Second reference electrode 71, 72, 73, 74 Inductors 81, 82, 83, 84 Reference potential terminal 90 Piezoelectric substrate 91, 92, 93, 94 Connection point 101, 102, 103, 104 Elastic wave device

Claims

A first wiring connected between the two signal terminals and formed on the surface of the piezoelectric substrate;
A series arm resonator connected in series to the first wiring and including a one-terminal acoustic wave element;
A first reference electrode connected to a first reference potential terminal via a first inductor and formed on the surface of the piezoelectric substrate;
A second wiring connected between a connection point provided on the first wiring and the first reference electrode;
A parallel arm resonator connected in series to the second wiring and including a one-terminal acoustic wave element;
A second reference electrode connected to a second reference potential terminal via a second inductor and electrically separated from the first reference electrode on the surface of the piezoelectric substrate;
Providing a third wiring connecting the second reference electrode and the connection point;
A first capacitive element is connected in series to the third wiring ,
The first capacitive element is an acoustic wave device connected in series to the first inductor via the second reference electrode .

Forming the first reference electrode on the first end side of the surface of the piezoelectric substrate;
The acoustic wave device according to claim 1, wherein the second reference electrode is formed on a second end side facing the first end side of the surface of the piezoelectric substrate.

3. The acoustic wave device according to claim 1, wherein the first reference potential terminal and the second reference potential terminal are formed as reference potential terminals having the same potential.

4. The acoustic wave device according to claim 3, wherein the same potential is a ground potential.

The elastic wave device according to claim 1, wherein a second capacitive element is connected in parallel to the parallel arm resonator.

A plurality of the series arm resonators are provided, and a third capacitor element is connected in parallel to the series arm resonator connected to one of the signal terminals without passing through another series arm resonator among the series arm resonators. acoustic wave apparatus according to any one claim of 請 Motomeko 1 to 5 that have been.

The elastic wave device according to claim 1, wherein an occupied area of the elastic wave device is substantially equal to an occupied area of the piezoelectric substrate.

The elastic wave device according to claim 1, wherein the first capacitive element is configured to sandwich a dielectric between two parallel flat plates.

The elastic wave device according to claim 1, wherein the first capacitive element includes a comb-shaped electrode.

The acoustic wave device according to claim 1, wherein the first capacitive element includes a plurality of capacitive elements.

The acoustic wave device according to claim 10, wherein each of the plurality of capacitive elements is connected in series to the first inductor via the second reference electrode.

The acoustic wave device according to any one of claims 1 to 11, wherein the first inductor is configured as one inductor.

The acoustic wave device according to claim 1, wherein the second inductor is configured as a single inductor.

The acoustic wave device according to claim 1, wherein the series arm resonator and the parallel arm resonator form a ladder type filter.

The acoustic wave device according to claim 1, further comprising a sealing body that seals the series arm resonator and the parallel arm resonator through an excitation space on a surface of the piezoelectric substrate.

Wherein at least one of the first inductor and the second inductor, the elastic wave device including請 Motomeko 15 wherein the conductor extending through the sealing body.

The acoustic wave device according to claim 1 , wherein the first reference electrode is divided into a plurality of reference electrode portions.

The elastic wave device according to claim 17 , comprising a plurality of the parallel arm resonators, wherein one of the parallel arm resonators is connected to one of the reference electrode portions.

The elastic wave device according to claim 18 , wherein the parallel arm resonators other than the one are connected to the reference electrode portions other than the one.

The elastic wave device according to any one of claims 1 to 19 , wherein any one of a surface acoustic wave, a boundary acoustic wave, and a bulk wave is used.