JP4363807B2

JP4363807B2 - Surface acoustic wave device and communication device using the same

Info

Publication number: JP4363807B2
Application number: JP2001289725A
Authority: JP
Inventors: 芝　　隆司; 勇次藤田; 真弓射手; 清磨近藤
Original assignee: Hitachi Media Electronics Co Ltd
Current assignee: Hitachi Media Electronics Co Ltd
Priority date: 2001-09-21
Filing date: 2001-09-21
Publication date: 2009-11-11
Anticipated expiration: 2021-09-21
Also published as: JP2003101370A

Description

【０００１】
【発明の属する技術分野】
本発明は、弾性表面波装置及びそれを用いた通信装置に係り、特に外部移相回路を必要とせず、かつ広帯域な低損失型の弾性表面波装置及びそれを用いた通信装置に関する。
【０００２】
【従来の技術】
従来の外部移相回路を必要としない縦続接続型低損失型弾性表面波装置は、２０００年IEEE ULTRASONICS SYMPOSIUM PROCEEDINGS ９９頁〜１０４頁により報告されている。
【０００３】
前記の縦続接続型一方向性電極は外部移相回路が不要である等の利点を有するが、その帯域は縦続接続段の整合によって決められるため、同一の基板を前提とすれば、帯域幅に限界が有るという欠点を有する。
【０００４】
【発明が解決しようとする課題】
前述のように従来の縦続接続型一方向性電極では、１段目から２段目へのI、Q 電極間の整合をとらなければならず、結果的に帯域幅に制限がある。また、外部に整合用の素子を設ければ帯域幅の問題はある程度回避できるが、外部回路が複雑となってしまう。
【０００５】
本発明の目的は、このような従来技術の欠点を解消し、外部整合回路を用いず、しかも整合による制限が無い、広帯域電極を有する弾性表面波装置及びそれを用いた通信装置を提供することにある。
【０００６】
【解決を解決するための手段】
前記目的は、弾性表面波の伝播路を少なくとも２個配置し、それぞれの伝播路に電極間距離L、弾性表面波音速Vを用いて、０°、１８０°とは異なる
φ_m ＝2 ≠L/V と表される幾何学的位相差φ_m だけ隔てて配置されたI、Qすだれ状電極を１組とし第１の伝播路にN組のI、Qすだれ状電極を表面波の入力側に近い側からI₁₁電極、Q₁₁電極、I₁₂電極、Q₁₂電極、----- I_1N電極、Q_1N電極とし、もう片方の伝播路におけるN組のI、Qすだれ状電極を表面波の主出力側に近い側からI₂₁電極、Q₂₁電極、I₂₂電極、Q₂₂電極、----- I_2N電極、Q_2N電極とした時、iを1以上N以下の整数として、I_1i電極とQ_2(N+1-i)電極、Q_1i電極とI_2(N+1-i)電極を電気的に接続する事により達成される。
【０００７】
φ_m を９０度にすれば第２トラックの入射波側の方向では、I1電極Q2電極を通ってくる波とQ1電極I2電極を通ってくる波は同相となり、逆方向に伝搬する波では、I1電極I2電極を通ってくる波とQ1電極Q2電極を通ってくる波の位相差は2 φ_m=180 度となり相殺される。
【０００８】
φ_m が９０度以外では原理的には逆方向に波が伝搬するが、方向性が充分な条件では低損失性も保持される。また、本発明の構成を用いれば、第２段伝播路に出現するインパルス応答は広がらないため、広帯域化が達成される。
【０００９】
以上、本発明の構造を用いれば、外部に移相回路を設ける事無く、広帯域な一方向性が得られる。
【００１０】
【発明の実施の形態】
以下、本発明の実施形態を図とともに説明する。図１に本発明の弾性表面波装置の構成図を示す。同図は広帯域化検討を行った縦続接続型一方向性電極の一例を示す図である。
【００１１】
弾性表面波基板１上に１段目伝播路側のすだれ状電極群２と２段目伝播路側のすだれ状電極群３が配置されている。１段目伝播路側のすだれ状電極群２の入力表面波側の１番目のI電極をI11、Q電極をQ11とし、２段目伝播路側のすだれ状電極群３の主出力表面波側の１番目のI電極をI21、Q電極をQ21とする。また２番目のI電極をI12、Q電極をQ12とし、２段目トラックの順方向側の２番目のI電極をI22、Q電極をQ22、同様に電極にナンバーを付け、N番目の１段目トラックのI電極をI1N、Q電極をQ1Nとし、２段目トラックの電極をI2N、Q電極をQ2Nとする。
【００１２】
各電極の１トラック目と２トラック目の電極の接続相手を次の表に示す。表の２段目と３段目に示した電極がそれぞれ接続される。
【００１３】
【表１】

この表をみれば、iを1以上N以下の整数として、I_1i電極とQ_2(N+1-i)電極、Q_1i電極とI_2(N+1-i)電極を電気的に接続すしている事がわかる。
【００１４】
図２に従来のグループ型弾性表面波装置の構成図を示す。通常はIすだれ状電極、Qすだれ状電極を配置し、外部にφ_e の位相差を生じせしめる電気的移相器４を配置し、φ_m φ_e を９０度としている。従来のグループ型弾性表面波装置は、大きく分けてスプリット型、ソリッド型に分類される。本発明の適用にも前記２種の構造を検討した。
【００１５】
図３は、ソリッド型を基本とした構造模式図である。第１の伝播路にはI1すだれ状電極１２、Q1すだれ状電極１3を配置し、第２のの伝播路にはI2すだれ状電極１４、Q2すだれ状電極１５を配置している。また、共通電極としてミアンダ電極５を配置している。
【００１６】
前記構造の有効性を確認するため、前述と同様の計算を行った。電極対数４対のソリッド型UDTをそれぞれ２トラックに３群配置し、それぞれは表１に示す規則に則り、I11電極とQ23電極、Q11電極とI23電極、I12電極とQ22電極、Q12電極とI22電極、I13電極とQ21電極、Q13電極とI21電極をそれぞれ接続した。前述と同様、基板は１２８度Y-X LiNbO3、開口は50lとした。
【００１７】
図４は、従来の構造の電極の特性図である。２つの伝播路に置かれるすだれ状電極はI、Q電極１組みで、電極対数を調整して、伝播路間の信号伝達は損失の少ないように設定している。基板は１２８度Y―X LiNb0₃を用い、シミュレーションツールとしては等価回路モデルを用いている。太い実線が順方向（主伝播方向）側の特性、細線が逆方向側の特性、丸い点が、第２伝播路に伝わらずに電極を通過していく波、三角点が入力表面波方向への反射波である。シミュレーション結果では、充分な方向性が得られているが、前述のように帯域幅が制限される。
【００１８】
図５に、今回の構造の周波数特性を示す。記号は図４と同様である。図４の特性に比べ、大幅な広帯域化（約３倍）を達成している。本構成では、通過帯域幅は１群の電極対数のみによって決定されるため、原理的には周波数帯域の制約は無い。また、計算によると、最適な電極グループ数（前記の例では３グループ）を選ぶ事により低損失化が達成される事も解った。本実施例ではφ_mを９０度としている。
【００１９】
本電極構造の有効性を確認するために、入力補助電極、順方向出力補助電極、逆方向出力補助電極を配置し実験による確認を行った。図６にその結果を示す。記号は図４と同様である。補助電極の中心周波数が、本発明の構成の広帯域型縦続接続一方向性電極の中心周波数とずれてしまったため、シミュレーション程の広帯域化は達成できなかったが、従来に比べ、約２〜３の広帯域化を達成している。
【００２０】
図７は、本発明の第２実施形態を示す図である。スプリット型を基本とした構造模式図である。第１の伝播路にはI1すだれ状電極、Q1すだれ状電極６を配置し、第２のの伝播路にはI2すだれ状電極、Q2すだれ状電極６を配置している。図には示していないが、前述と同様、それぞれの電極群はそれぞれの伝播路に複数組み配置されている。
【００２１】
図８は、本発明の第３実施形態を示す図である。本発明の広帯域型縦続接続一方向性電極７を、入力すだれ状電極８と出力すだれ電極９の両側に配置した。本実施例を用いれば、弾性表面波エネルギーを閉じ込め、低損失化を図る事ができる。
【００２２】
図９は、本発明の第４実施形態を示す図である。本実施形態では、本発明の広帯域型縦続接続一方向性電極の実装配線例を示している。本発明の複雑な配線を可能とするため、互いに接続が必要な電極のボンディングパッドを図のように並べ、それぞれをワイヤボンディング１０の接続線が、互いに平行になるように配置している。また、同時にミアンダ電極部の導体抵抗損失を小さくするため、各ブロック毎に配線１１により接続を行っている。
【００２３】
図１０は、本発明の第５実施形態を示す図である。本実施形態では、前記第４実施形態のSAWチップをフリップチップ実装したものである。配線基板側の配線パターン１２は互いに平行になるように配置され、ボンディング接続部に相対する位置に電極パッド１３が配置されている。
【００２４】
図１１は本実施形態のフリップチップ実装部の断面図である。図１０と同一箇所は同一記号で示している。配線基板１６上に配線パターン１２が形成され、SAWチップとの接続はバンプ１５により行われている。本実施形態を用いれば、複雑な接続も比較的容易に行う事ができる。
【００２５】
本発明の実施形態に係る弾性表面波装置は、例えば携帯電話などの通信装置のフィルタ部に用いられる。本発明の弾性表面波装置は回路が簡略化可能であると共に、低損失、広帯域特性なフィルタが可能となるため、通信装置の小形化、高性能化に有効である。
【００２６】
【発明の効果】
以上説明したように、本発明によれば外部移相回路を用いず、広帯域な低損失フィルタが可能な為、回路の簡略化、広帯域化に有効である。
【図面の簡単な説明】
【図１】本発明の一実施形態による弾性表面波装置の模式図である。
【図２】従来のグループ型一方向性電極の模式図である。
【図３】本発明の第１実施形態による弾性表面波装置の主要構成部分（ソリッド型）を示す模式図である。
【図４】従来の縦続接続型一方向性電極の周波数特性図である。
【図５】本発明の第１実施形態による広帯域型縦続接続一方向性電極の周波数特性図である。
【図６】本発明の第１実施形態による広帯域型縦続接続一方向性電極の周波数特性図である。
【図７】本発明の第２実施形態による弾性表面波装置の主要構成部分（スプリット型）を示す模式図である。
【図８】本発明の第３実施形態による弾性表面波装置の模式図である。
【図９】本発明の第４実施形態による弾性表面波装置の電気配線模式図である。
【図１０】本発明の第５実施形態による弾性表面波装置の電気配線模式図である。
【図１１】本発明の第５実施形態の弾性表面波装置の断面模式図である。
【符号の説明】
１弾性表面波基板
３，４すだれ状電極群
６すだれ状電極
７一方向性電極
８，９すだれ状電極
１０ワイヤボンディング
１２配線パターン
１３電極パッド
１５バンプ
１６配線基板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surface acoustic wave device and a communication device using the same, and more particularly to a broadband low-loss surface acoustic wave device that does not require an external phase shift circuit and a communication device using the same.
[0002]
[Prior art]
A conventional cascade-connected low-loss surface acoustic wave device that does not require a conventional external phase shift circuit is reported in 2000 IEEE ULTRASONICS SYMPOSIUM PROCEEDINGS, pages 99-104.
[0003]
The cascade connection type unidirectional electrode has an advantage that an external phase shift circuit is not required, but its bandwidth is determined by matching of cascade connection stages. It has the disadvantage of being limited.
[0004]
[Problems to be solved by the invention]
As described above, in the conventional cascade-connected unidirectional electrode, the I and Q electrodes must be matched from the first stage to the second stage, resulting in a limited bandwidth. If a matching element is provided outside, the bandwidth problem can be avoided to some extent, but the external circuit becomes complicated.
[0005]
SUMMARY OF THE INVENTION An object of the present invention is to provide a surface acoustic wave device having a broadband electrode and a communication device using the same, which eliminates the drawbacks of the prior art and does not use an external matching circuit and is not limited by matching. It is in.
[0006]
[Means for solving the problem]
The purpose is to arrange at least two propagation paths for surface acoustic waves, and use the distance L between electrodes and the surface acoustic wave sound velocity V for each propagation path, and φ _m = 2 ≠ L different from 0 ° and 180 °. / geometric phase difference is represented as V phi _m only separated by placed I, Q interdigital electrode pair and then N sets of I to the first propagation path, the input side of the surface wave Q IDT I ₁₁ electrode, Q ₁₁ electrode, I ₁₂ electrode, Q ₁₂ electrode, ----- I _1N electrode, Q _1N electrode from the side close to _N, and N pairs of I and Q interdigital electrodes in the other propagation path I ₂₁ electrodes from the side closer to the main output of the surface wave, Q ₂₁ electrodes, I ₂₂ electrodes, Q ₂₂ electrodes, ----- I _2N electrodes, when the Q _2N electrodes, i one or more N an integer This is achieved by electrically connecting the I _1i electrode and the Q _{2 (N + 1-i)} electrode, and the Q _1i electrode and the I _{2 (N + 1-i)} electrode.
[0007]
If φ _m is 90 degrees, the wave passing through the I1 electrode Q2 electrode and the wave passing through the Q1 electrode I2 electrode are in phase in the direction of the incident wave side of the second track, and in the wave propagating in the opposite direction, The phase difference between the wave that passes through the I1 electrode and the I2 electrode and the wave that passes through the Q1 electrode and the Q2 electrode is 2 φ _m = 180 degrees, which cancels out.
[0008]
Waves propagate in the opposite direction in principle when φ _m is other than 90 degrees, but low loss is maintained under sufficient directionality conditions. In addition, if the configuration of the present invention is used, the impulse response that appears in the second stage propagation path does not spread, so that a wider band is achieved.
[0009]
As described above, if the structure of the present invention is used, a broadband unidirectionality can be obtained without providing an external phase shift circuit.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration diagram of a surface acoustic wave device according to the present invention. This figure is a diagram showing an example of a cascade connection type unidirectional electrode which has been studied for wide band.
[0011]
An interdigital electrode group 2 on the first stage propagation path side and an interdigital electrode group 3 on the second stage propagation path side are arranged on the surface acoustic wave substrate 1. The first I electrode on the input surface wave side of the interdigital electrode group 2 on the first stage propagation path side is I11, the Q electrode is Q11, and 1 on the main output surface wave side of the interdigital electrode group 3 on the second stage propagation path side. The first I electrode is I21 and the Q electrode is Q21. Also, the second I electrode is I12, the Q electrode is Q12, the second I electrode on the forward direction side of the second track is I22, the Q electrode is Q22, and the electrode is numbered in the same way. The I electrode of the second track is I1N, the Q electrode is Q1N, the electrode of the second track is I2N, and the Q electrode is Q2N.
[0012]
The following table shows the connection partner of the first and second track electrodes of each electrode. The electrodes shown in the second and third stages of the table are connected to each other.
[0013]
[Table 1]

Looking at the table, electrically connecting the i as 1 or more N an integer, I _1i electrode and Q _{2 (N + 1i)} electrodes, Q _1i electrode and I ₂ a _{(N + 1i)} electrode You can see that it is sipping.
[0014]
FIG. 2 shows a configuration diagram of a conventional group type surface acoustic wave device. Usually, an I interdigital electrode and a Q interdigital electrode are arranged, and an electrical phase shifter 4 that generates a phase difference of φ _e is arranged outside, and φ _m φ _{e is set} to 90 degrees. Conventional group type surface acoustic wave devices are roughly classified into a split type and a solid type. The two types of structures were also examined for application of the present invention.
[0015]
FIG. 3 is a schematic structural diagram based on a solid type. An I1 interdigital electrode 12 and a Q1 interdigital electrode 13 are disposed in the first propagation path, and an I2 interdigital electrode 14 and a Q2 interdigital electrode 15 are disposed in the second propagation path. A meander electrode 5 is disposed as a common electrode.
[0016]
In order to confirm the effectiveness of the structure, the same calculation as described above was performed. Three groups of solid UDTs with 4 pairs of electrodes are arranged on 2 tracks, respectively, and in accordance with the rules shown in Table 1 , each of I11 electrode and Q23 electrode, Q11 electrode and I23 electrode, I12 electrode and Q22 electrode, Q12 electrode and I22 The electrode, the I13 electrode and the Q21 electrode, and the Q13 electrode and the I21 electrode were connected to each other. As before, the substrate was 128 degrees YX LiNbO3 and the opening was 50 l.
[0017]
FIG. 4 is a characteristic diagram of an electrode having a conventional structure. The interdigital electrodes placed in the two propagation paths are one set of I and Q electrodes, and the number of electrode pairs is adjusted so that signal transmission between the propagation paths is reduced. The substrate is 128 degrees YX LiNb0 ₃ and an equivalent circuit model is used as a simulation tool. The thick solid line is the characteristic on the forward direction (main propagation direction) side, the thin line is the characteristic on the reverse direction side, the round point is a wave that passes through the electrode without passing through the second propagation path, and the triangular point is in the direction of the input surface wave Is the reflected wave. In the simulation results, sufficient directionality is obtained, but the bandwidth is limited as described above.
[0018]
FIG. 5 shows the frequency characteristics of the current structure. The symbols are the same as in FIG. Compared to the characteristics shown in FIG. 4, a significant increase in bandwidth (about 3 times) is achieved. In this configuration, since the passband width is determined only by the number of electrode pairs in one group, there is no restriction on the frequency band in principle. Further, according to the calculation, it has been found that the loss reduction can be achieved by selecting the optimum number of electrode groups (three groups in the above example). In this embodiment, φ _m is 90 degrees.
[0019]
In order to confirm the effectiveness of this electrode structure, an input auxiliary electrode, a forward output auxiliary electrode, and a reverse output auxiliary electrode were arranged and confirmed by experiments. The result is shown in FIG. The symbols are the same as in FIG. Since the center frequency of the auxiliary electrode has deviated from the center frequency of the broadband cascade-connected unidirectional electrode having the configuration of the present invention, it has not been possible to achieve a wide bandwidth as much as the simulation, but compared with the conventional case, about 2-3. Broadband has been achieved.
[0020]
FIG. 7 is a diagram showing a second embodiment of the present invention. It is a structural schematic diagram based on the split type. An I1 interdigital electrode and a Q1 interdigital electrode 6 are disposed in the first propagation path, and an I2 interdigital electrode and a Q2 interdigital electrode 6 are disposed in the second propagation path. Although not shown in the drawing, a plurality of sets of each electrode group are arranged in each propagation path as described above.
[0021]
FIG. 8 is a diagram showing a third embodiment of the present invention. Broadband cascaded unidirectional electrodes 7 of the present invention are arranged on both sides of the input interdigital electrode 8 and the output interdigital electrode 9. If this embodiment is used, the surface acoustic wave energy can be confined and the loss can be reduced.
[0022]
FIG. 9 is a diagram showing a fourth embodiment of the present invention. In the present embodiment, a mounting wiring example of the broadband type cascade connection unidirectional electrode of the present invention is shown. In order to enable complicated wiring of the present invention, bonding pads of electrodes that need to be connected to each other are arranged as shown in the drawing, and are arranged so that the connecting lines of the wire bonding 10 are parallel to each other. At the same time, in order to reduce the conductor resistance loss of the meander electrode portion, connection is made by wiring 11 for each block.
[0023]
FIG. 10 is a diagram showing a fifth embodiment of the present invention. In this embodiment, the SAW chip of the fourth embodiment is flip-chip mounted. The wiring patterns 12 on the wiring board side are arranged so as to be parallel to each other, and the electrode pads 13 are arranged at positions facing the bonding connection portions.
[0024]
FIG. 11 is a cross-sectional view of the flip chip mounting portion of the present embodiment. The same parts as those in FIG. 10 are indicated by the same symbols. A wiring pattern 12 is formed on the wiring substrate 16 and is connected to the SAW chip by bumps 15. By using this embodiment, complicated connections can be made relatively easily.
[0025]
A surface acoustic wave device according to an embodiment of the present invention is used in a filter unit of a communication device such as a mobile phone. The surface acoustic wave device of the present invention can be simplified in circuit, and can be a filter with low loss and wideband characteristics, which is effective for miniaturization and high performance of a communication device.
[0026]
【The invention's effect】
As described above, according to the present invention, since a wideband low-loss filter is possible without using an external phase shift circuit, it is effective in simplifying the circuit and increasing the bandwidth.
[Brief description of the drawings]
FIG. 1 is a schematic view of a surface acoustic wave device according to an embodiment of the present invention.
FIG. 2 is a schematic view of a conventional group-type unidirectional electrode.
FIG. 3 is a schematic view showing main components (solid type) of the surface acoustic wave device according to the first embodiment of the present invention.
FIG. 4 is a frequency characteristic diagram of a conventional cascade-connected unidirectional electrode.
FIG. 5 is a frequency characteristic diagram of the broadband cascade-connected unidirectional electrode according to the first embodiment of the present invention.
FIG. 6 is a frequency characteristic diagram of the broadband cascade-connected unidirectional electrode according to the first embodiment of the present invention.
FIG. 7 is a schematic view showing main components (split type) of a surface acoustic wave device according to a second embodiment of the present invention.
FIG. 8 is a schematic view of a surface acoustic wave device according to a third embodiment of the present invention.
FIG. 9 is a schematic electrical wiring diagram of a surface acoustic wave device according to a fourth embodiment of the present invention.
FIG. 10 is a schematic electric wiring diagram of a surface acoustic wave device according to a fifth embodiment of the present invention.
FIG. 11 is a schematic sectional view of a surface acoustic wave device according to a fifth embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Surface acoustic wave substrate 3, 4 Interdigital electrode group 6 Interdigital electrode 7 Unidirectional electrode 8, 9 Interdigital electrode 10 Wire bonding 12 Wiring pattern 13 Electrode pad 15 Bump 16 Wiring substrate

Claims

In a surface acoustic wave device in which input and output interdigital electrodes are arranged on a surface acoustic wave substrate,
At least two surface acoustic wave propagation paths are arranged and the geometric phase difference determined by the geometric position of the interdigital electrode and the sound velocity and frequency of the surface acoustic wave is deviated from 0 degrees or 180 degrees. retardation and phi _m only separated by placed I, the Q interdigital electrode pair and the first N sets the propagation path of the I, Q interdigital electrodes I ₁₁ electrodes from the side close to the input side of the surface wave, Q ₁₁ electrode, I ₁₂ electrode, Q ₁₂ electrode, ----- I _1N electrode, Q _1N electrode,
N pairs of I and Q interdigital electrodes in the other propagation path from the side close to the main output side of the surface wave I ₂₁ electrode, Q ₂₁ electrode, I ₂₂ electrode, Q ₂₂ electrode, ----- I _2N electrode When using a Q _2N electrode,
i is an integer of 1 or more and N or less, the I _1i electrode and the Q _{2 (N + 1-i)} electrode, the Q _1i electrode and the I _{2 (N + 1-i)} electrode are electrically connected, and the electrode group A surface acoustic wave device characterized in that a surface acoustic wave is radiated more strongly in a desired direction when an input signal is transmitted to the other propagation path.

2. The surface acoustic wave device according to claim 1, wherein at least two propagation paths of the surface acoustic wave are arranged, and at least two interdigital electrodes are arranged in each propagation path, and the geometry of the two interdigital electrodes is arranged. A surface acoustic wave device characterized in that a geometric phase difference φ _m determined by a geometric position, sound velocity and frequency of a surface acoustic wave is 90 degrees.

2. The surface acoustic wave device according to claim 1, wherein at least two propagation paths of the surface acoustic wave are arranged, and at least two interdigital electrodes are arranged in each propagation path, and the two interdigital electrodes are geometrically arranged. A surface acoustic wave device using a solid group-type electrode as a means for separating by a geometric phase difference φ _m .

2. The surface acoustic wave device according to claim 1, wherein at least two propagation paths of the surface acoustic wave are arranged, and at least two interdigital electrodes are arranged in each propagation path, and the two interdigital electrodes are geometrically arranged. A surface acoustic wave device using a split-type group electrode as a means for separating by a geometric phase difference φ _m .

2. The surface acoustic wave device according to claim 1, wherein the bonding pads are arranged so that the straight lines connecting the centers of the opposing bonding pads for connecting the electrodes of the first and second propagation paths are substantially parallel to each other. A surface acoustic wave device characterized by being arranged.

6. The surface acoustic wave device according to claim 5, wherein mounting of the surface acoustic wave chip is directly connected to the wiring substrate by flip chip bonding, and wirings facing the bonding pads are wired substantially in parallel. Surface acoustic wave device.

2. The surface acoustic wave device according to claim 1, wherein at least two propagation paths of the surface acoustic wave are arranged, and at least four interdigital electrodes are arranged in each propagation path, and each of them constitutes a set 2. The geometric phase difference φ _m determined by the geometric position of each interdigital electrode and the sound velocity and frequency of the surface acoustic wave is removed from 0 ° or 180 °, and each interdigital electrode is independently connected to the other propagation path. A surface acoustic wave device, characterized in that each of the two interdigital electrodes connected to the interdigital electrodes is arranged symmetrically with respect to the opposing input or output electrodes .

8. A communication apparatus using the surface acoustic wave device according to claim 1 as a filter unit.