JPH06232682A - Surface acoustic wave resonator and surface acoustic wave filter - Google Patents
Surface acoustic wave resonator and surface acoustic wave filterInfo
- Publication number
- JPH06232682A JPH06232682A JP2001793A JP2001793A JPH06232682A JP H06232682 A JPH06232682 A JP H06232682A JP 2001793 A JP2001793 A JP 2001793A JP 2001793 A JP2001793 A JP 2001793A JP H06232682 A JPH06232682 A JP H06232682A
- Authority
- JP
- Japan
- Prior art keywords
- surface acoustic
- acoustic wave
- resonator
- filter
- electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Landscapes
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、伝搬波動のモード結合
によるスプリアスを低減した弾性表面波共振子、また
は、弾性表面波フィルタ、ならびに、弾性表面波共振子
型フィルタに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface acoustic wave resonator, a surface acoustic wave filter, and a surface acoustic wave resonator type filter in which spurious due to mode coupling of propagating waves is reduced.
【０００２】[0002]
【従来の技術】弾性表面波共振子は、ＵＨＦ、ＶＨＦ帯
での水晶振動子に比べ、基本発振が可能で、小型化、高
Ｑを実現できることから、各種通信装置、家電製品に適
用されている。弾性表面波共振子の基本的な構成は大き
く分けると、入出力用すだれ状電極（以下、ＩＤＴとい
う）の両側に反射器を設けたキャビティ型、反射器を設
けないＩＤＴ型の２つがある。またこの弾性表面波共振
子の基板材料として、水晶基板が、温度特性の点から数
多く用いられている。特開平２−７５２１５号公報に
は、近接して配置した２つの弾性表面波共振子を弾性的
に結合させた場合、対称モードと反対称モードの２つの
振動モードが生じること、この対称モードの共振周波数
と反対称モードの***振周波数を一致させ所望の特性の
多重モード共振器型弾性表面波フィルタを得ることにつ
いて述べられており、ＩＤＴの端部に、弾性表面波の伝
搬方向に直角方向に伸びる導体パタ−ン設けたものであ
る。この導体パタ−ンを設けることにより、ＩＤＴ端部
での不要な振動モードの発生、および不要なモード結合
を防ぐ効果がある。図１０は、開口長Ｗ１と電極指非交
差開口部Ｗ２の比が８の、従来の弾性表面波共振子のイ
ンピーダンス特性を示したものであり、共振周波数Ｆｒ
と、***振周波数Ｆａの間（９５０ＭＨｚから９５５Ｍ
Ｈｚ付近）で不要なスプリアスが発生していることがわ
かる。2. Description of the Related Art Surface acoustic wave resonators are applicable to various communication devices and home electric appliances because they are capable of fundamental oscillation, smaller in size and higher in Q than crystal oscillators in the UHF and VHF bands. There is. The basic structure of the surface acoustic wave resonator is roughly divided into two types: a cavity type in which reflectors are provided on both sides of an input / output interdigital transducer (hereinafter referred to as an IDT) and an IDT type in which no reflector is provided. Further, as a substrate material for this surface acoustic wave resonator, many quartz substrates are used in terms of temperature characteristics. JP-A-2-75215 discloses that when two surface acoustic wave resonators arranged close to each other are elastically coupled, two vibration modes, a symmetric mode and an antisymmetric mode, occur. It is described that the resonance frequency and the anti-resonance frequency of the anti-symmetric mode are matched to obtain a multi-mode resonator type surface acoustic wave filter having desired characteristics. The IDT has a direction perpendicular to the propagation direction of the surface acoustic wave. It is provided with a conductor pattern that extends to. By providing this conductor pattern, there is an effect of preventing generation of an unnecessary vibration mode at the end of the IDT and unnecessary mode coupling. FIG. 10 shows the impedance characteristics of a conventional surface acoustic wave resonator in which the ratio of the opening length W1 to the electrode finger non-intersecting opening W2 is 8, and the resonance frequency Fr is shown.
And the anti-resonance frequency Fa (950MHz to 955M
It can be seen that unnecessary spurious is generated around (Hz).
【０００３】[0003]
【発明が解決しようとする課題】圧電性基板上に形成し
たＩＤＴに励振する波のモードは、圧電性基板の種類、
基板のカット角、基板表面伝搬路の電気的状態により違
ってくる。タンタル酸リチウム単結晶基板（ＬｉＴａＯ
3）、または、ニオブ酸リチウム単結晶基板（ＬｉＮｂ
Ｏ3）においては、基板のカット角によって、擬似弾性
表面波（Leaky Surface Acoustic Wave；以下、ＬＳＡ
Ｗという）、もしくは、バルク波（Surface Skimming B
ulk Wave；以下、ＳＳＢＷという）が主伝搬波動とな
り、結合係数が通常のレ−リ−モードの弾性表面波より
大きくなる特徴がある。特に、ＬｉｔａＯ3３６度回転
Ｙ板Ｘ軸伝搬では、伝搬路が自由表面ではＳＳＢＷが主
伝搬波動となり、他方、伝搬路が短絡表面、すなわち、
金属電極下では、ＬＳＡＷが主伝搬波動となることが知
られている。また、上記従来例の水晶基板においては、
レ−リ−モードのいわゆる表面波（Ｓｕｒｆａｃｅ Ａ
ｃｏｕｓｔｉｃ Ｗａｖｅ）が主伝搬波動となる。但
し、上記従来例の水晶基板は、温度特性には優れるが、
結合係数が小さく、共振子を組み合わせたフィルタとし
て応用する場合、共振周波数と***振周波数間の周波数
幅が取れないので、広帯域のフィルタには不都合であ
る。この広帯域フィルタには、ＬｉＴａＯ3基板または
ＬｉＮｂＯ3が適している。中でも、結合係数の大きな
ＬＳＡＷを生ずるカット角の基板が適している。しかし
発明者らは、これ等の基板を用いた場合に、上記説明し
たＬＳＡＷおよびＳＳＢＷの２つの波が発生し、特有の
スプリアスピ−クを生ずる問題点を見出した。特に弾性
表面波共振子のインピーダンス特性においては、弾性表
面波共振子の共振周波数と***振周波数との間で、ＬＳ
ＡＷとＳＳＢＷの結合と見られる不要スプリアスが発生
する。このため、弾性表面波共振子を組み合わせた弾性
表面波共振子型フィルタでは、帯域内で、不要なリップ
ルが発生する不具合を生じる。発明者らは、この不要ス
プリアスがＬＳＡＷとＳＳＢＷとの結合が関与している
ことを明らかにした。本発明は、上記知見に基づき、従
来の問題点を解決し、弾性表面波共振子の共振周波数と
***振周波数との間でのモード結合と見られる不要スプ
リアスがない弾性表面波共振子、および、弾性表面波共
振子を組み合わせた弾性表面波共振子型フィルタ、なら
びに、弾性表面波フィルタを提供することを目的とす
る。The mode of the wave excited on the IDT formed on the piezoelectric substrate depends on the type of the piezoelectric substrate,
It depends on the cut angle of the substrate and the electrical condition of the substrate surface propagation path. Lithium tantalate single crystal substrate (LiTaO
3 ) or a lithium niobate single crystal substrate (LiNb
O 3 ), depending on the cut angle of the substrate, a quasi surface acoustic wave (Leaky Surface Acoustic Wave;
W) or bulk wave (Surface Skimming B
ulk Wave; hereinafter referred to as SSBW) is a main propagation wave, and the coupling coefficient is larger than that of a normal Rayleigh mode surface acoustic wave. Particularly, in LitaO 3 36-degree rotating Y-plate X-axis propagation, SSBW becomes the main propagation wave when the propagation path is a free surface, while the propagation path is a short-circuit surface, that is,
It is known that LSAW becomes the main propagation wave under the metal electrode. Further, in the above-mentioned conventional quartz substrate,
Rayleigh mode so-called surface wave (Surface A)
The acoustic wave is the main propagating wave. However, the quartz substrate of the above-mentioned conventional example is excellent in temperature characteristics,
When applied as a filter having a small coupling coefficient and a combination of resonators, a frequency range between the resonance frequency and the anti-resonance frequency cannot be obtained, which is inconvenient for a wide band filter. A LiTaO 3 substrate or LiNbO 3 is suitable for this broadband filter. Above all, a substrate having a cut angle that produces an LSAW having a large coupling coefficient is suitable. However, the inventors have found a problem that, when these substrates are used, the two waves of LSAW and SSBW described above are generated, and a spurious peak peculiar to them is generated. Particularly, in the impedance characteristic of the surface acoustic wave resonator, the LS between the resonance frequency and the antiresonance frequency of the surface acoustic wave resonator is
Unwanted spurious that appears to be a combination of AW and SSBW occurs. Therefore, in the surface acoustic wave resonator type filter in which the surface acoustic wave resonators are combined, there arises a problem that unnecessary ripples occur within the band. The inventors have revealed that this unnecessary spurious is involved in the binding of LSAW and SSBW. The present invention, based on the above findings, solves the conventional problems, and has a surface acoustic wave resonator having no unnecessary spurious that is considered as mode coupling between the resonance frequency and the antiresonance frequency of the surface acoustic wave resonator, and An object of the present invention is to provide a surface acoustic wave resonator type filter in which surface acoustic wave resonators are combined, and a surface acoustic wave filter.
【０００４】[0004]
【課題を解決するための手段】上記目的を達成するため
に、本発明は、圧電性基板上に形成した弾性表面波共振
子または弾性表面波フィルタの、共振子の開口長Ｗ１と
弾性表面波共振子または弾性表面波フィルタを構成する
ＩＤＴの電極指非交差部Ｗ２の比を１４以上（Ｗ１／Ｗ
２≧１４）と規定するか、または、ＩＤＴの電極指非交
差部とバスバー部分を吸音材で塗布した構成により解決
される。In order to achieve the above object, the present invention provides a surface acoustic wave resonator or a surface acoustic wave filter formed on a piezoelectric substrate, the aperture length W1 of the resonator and the surface acoustic wave. The ratio of the electrode finger non-intersecting portion W2 of the IDT forming the resonator or the surface acoustic wave filter is 14 or more (W1 / W
2 ≧ 14), or a structure in which the electrode finger non-intersecting portion of the IDT and the bus bar portion are coated with a sound absorbing material is solved.
【０００５】[0005]
【作用】上記のような手段をとることにより、弾性表面
波共振子のインピーダンス特性において、不要スプリア
スの発生を低減できる。すなわち、ＬｉＴａＯ3基板上
に形成されたＩＤＴは、金属電極下すなわちＩＤＴ交差
部分ではＬＳＡＷが主伝搬波動となり、自由表面すなわ
ちＩＤＴの電極指非交差部分ではＳＳＢＷが主伝搬波動
となる。このため、弾性表面波共振子の開口長Ｗ１と共
振子を構成するＩＤＴの電極指非交差部Ｗ２の比を１４
以上（Ｗ１／Ｗ２≧１４）と規定する、またはＩＤＴの
電極指非交差部とバスバー部分を吸音材で塗布すること
で、電極指非交差部分で発生するＬＳＡＷを減衰させ、
このＬＳＡＷにより発生するＳＳＢＷの波の強度レベル
を低減し、ＩＤＴ交差部分へのＳＳＢＷの侵入を低減で
きる。このため、ＳＳＢＷとＬＳＡＷの波のモード結合
を低減することができる。また、弾性表面波フィルタに
おいても、同様の作用がある。By taking the above means, it is possible to reduce the generation of unnecessary spurious in the impedance characteristics of the surface acoustic wave resonator. That is, in the IDT formed on the LiTaO 3 substrate, the LSAW is the main propagating wave under the metal electrode, that is, the IDT crossing portion, and the SSBW is the main propagating wave on the free surface, that is, the electrode finger non-crossing portion of the IDT. Therefore, the ratio of the aperture length W1 of the surface acoustic wave resonator to the electrode finger non-intersecting portion W2 of the IDT forming the resonator is 14%.
By defining the above (W1 / W2 ≧ 14), or by applying the sound absorbing material to the electrode finger non-intersection portion and the bus bar portion of the IDT, the LSAW generated in the electrode finger non-intersection portion is attenuated,
The intensity level of the SSBW wave generated by this LSAW can be reduced, and the invasion of SSBW into the IDT intersection can be reduced. Therefore, mode coupling of waves of SSBW and LSAW can be reduced. The same effect can be obtained in the surface acoustic wave filter.
【０００６】[0006]
【実施例】以下、本発明を図面を用いて説明する。図１
は、本発明の第１の実施例を示すもので、１段のすだれ
状電極（ＩＤＴ）型弾性表面波共振子に関するものであ
る。このＩＤＴ型弾性表面波共振子は、３６度回転Ｙ軸
切断Ｘ軸伝搬のタンタル酸リチウム（ＬｉＴａＯ3）か
らなる圧電性基板１の上に、ワイヤリング用のボンディ
ングパッド２を有するとともにＩＤＴを構成する電極指
３とこの電極指を電気的に接続するバスバー４からなる
一対の電極が形成されて構成されている。第１の実施例
は、この電極指３の対数が３００本であるが、図１では
省略して模式的に図示している。また、このＩＤＴの共
振子の開口長Ｗ１は７０μｍに設定されており、電極指
３が交差しない電極指非交差開口部Ｗ２は５μｍに設定
されており、開口長Ｗ１と電極指非交差開口部Ｗ２の比
は１４に設定されている。また、電極指３の電極線幅
と、スペース部分の幅は共に１．２μｍである。この弾
性表面波共振子の電極指材料は、アルミニウム−チタン
合金（Ａｌ−Ｔｉ合金）を用いてＤＣマグネトロンスパ
ッタ法により電極膜厚１００ｎｍに成膜して構成されて
いる。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. Figure 1
Shows a first embodiment of the present invention and relates to a one-step interdigital transducer (IDT) type surface acoustic wave resonator. This IDT-type surface acoustic wave resonator has a bonding pad 2 for wiring on a piezoelectric substrate 1 made of lithium tantalate (LiTaO 3 ) which is rotated by 36 degrees and cut by Y-axis and propagated by X-axis, and constitutes an IDT. A pair of electrodes composed of an electrode finger 3 and a bus bar 4 for electrically connecting the electrode finger 3 is formed. Although the number of pairs of the electrode fingers 3 is 300 in the first embodiment, it is omitted in FIG. Further, the opening length W1 of the resonator of this IDT is set to 70 μm, the electrode finger non-intersecting opening W2 where the electrode fingers 3 do not intersect is set to 5 μm, and the opening length W1 and the electrode finger non-intersecting opening are set. The ratio of W2 is set to 14. The electrode line width of the electrode finger 3 and the width of the space portion are both 1.2 μm. The electrode finger material of this surface acoustic wave resonator is formed by using an aluminum-titanium alloy (Al-Ti alloy) to form an electrode film having a thickness of 100 nm by a DC magnetron sputtering method.
【０００７】図２は、第１の実施例の１段のＩＤＴ型弾
性表面波共振子の周波数−インピーダンス特性を示す図
であり、共振周波数Ｆｒは９３５ＭＨｚ、***振周波数
Ｆａは９６５ＭＨｚである。この共振周波数Ｆｒと***
振周波数Ｆａとの間隔は、近似的には、FIG. 2 is a diagram showing the frequency-impedance characteristic of the one-stage IDT type surface acoustic wave resonator of the first embodiment. The resonance frequency Fr is 935 MHz and the antiresonance frequency Fa is 965 MHz. The interval between the resonance frequency Fr and the anti-resonance frequency Fa is approximately
【数１】 で表わされ、この間隔が、フィルタの帯域幅や肩特性に
関係する。ＩＤＴ型弾性表面波共振子の集中定数等価回
路は、共振抵抗をＲ，制動容量をＣｄとし、共振のＬ，
Ｃから、共振周波数Ｆｒと、***振周波数Ｆａは、[Equation 1] This spacing is related to the bandwidth and shoulder characteristics of the filter. The lumped constant equivalent circuit of the IDT type surface acoustic wave resonator has a resonance resistance R, a damping capacitance Cd, a resonance L,
From C, the resonance frequency Fr and the anti-resonance frequency Fa are
【数２】 [Equation 2]
【数３】 で表わされる。ここで、制動容量Ｃｄは、[Equation 3] It is represented by. Here, the braking capacity Cd is
【数４】 で表わされる。[Equation 4] It is represented by.
【０００８】この図からわかるように、共振子の開口長
と電極指非交差開口部の比（Ｗ１／Ｗ２）を１４と大き
く規定することで、電極指交差部Ｗ３での主伝搬波動で
あるＬＳＡＷと、電極指非交差開口部での主伝搬波動で
あるＳＳＢＷとの不要波の結合が低減され、従来の弾性
表面波共振子で発生した、共振子の共振周波数と***振
周波数との間で発生する不要スプリアスが低減される。
尚、この不要スプリアスは、共振子の開口長と電極指非
交差開口部の比（Ｗ１／Ｗ２）が１４以上では発生しな
いことが、実験からわかった。また、同じ電極構成で、
ニオブ酸リチウム（ＬｉＮｂＯ3）基板上に作成した共
振子では、上記不要スプリアスは発生せず、タンタル酸
リチウム基板にのみ発生するＳＳＢＷに特有な現象であ
ることがわかった。As can be seen from this figure, when the ratio of the aperture length of the resonator and the electrode finger non-intersecting aperture (W1 / W2) is largely defined as 14, it is the main propagating wave at the electrode finger intersecting part W3. The coupling of the unwanted wave between the LSAW and the SSBW that is the main propagation wave in the electrode finger non-intersecting opening is reduced, and the resonance frequency and anti-resonance frequency of the resonator generated in the conventional surface acoustic wave resonator are reduced. The unnecessary spurious that occurs in is reduced.
Experiments have shown that this unnecessary spurious does not occur when the ratio of the aperture length of the resonator to the electrode finger non-intersecting aperture (W1 / W2) is 14 or more. Also, with the same electrode configuration,
It was found that in the resonator formed on the lithium niobate (LiNbO 3 ) substrate, the above-mentioned unnecessary spurious does not occur, and it is a phenomenon unique to SSBW which occurs only on the lithium tantalate substrate.
【０００９】図３は、本発明の第２の実施例の２段ＩＤ
Ｔ型弾性表面波共振子の平面図である。この弾性表面波
共振子は、第１の実施例の弾性表面波共振子をバスバー
４を会して２つ直列に接続した２段ＩＤＴ型弾性表面波
共振子である。また、図３は、図１の第１の実施例のイ
ンピーダンス特性を示している。図３からわかるよう
に、Ｗ１／Ｗ２の比を大きく規定することで、電極指交
差部Ｗ３での主伝搬波動であるＬＳＡＷと、電極指非交
差開口部での主伝搬波動であるＳＳＢＷとの不要波の結
合が低減され、図１０の従来ＳＡＷ共振子で発生した、
共振子の共振周波数と***振周波数との間で発生する不
要スプリアスが低減される。尚、この不要スプリアス
は、Ｗ１／Ｗ２の比が１４以上では発生しないことが、
実験からわかった。また図２に示す弾性表面波共振子で
も、同様の結果が得られた。また、同じ電極構成で、Ｌ
ｉＮｂＯ3基板上に作成した共振子では、上記不要スプ
リアスは発生せず、ＳＳＢＷ特有な現象であることがわ
かった。FIG. 3 shows a two-stage ID according to the second embodiment of the present invention.
It is a top view of a T-type surface acoustic wave resonator. This surface acoustic wave resonator is a two-stage IDT-type surface acoustic wave resonator in which two surface acoustic wave resonators according to the first embodiment are connected in series with the bus bar 4 interposed therebetween. Further, FIG. 3 shows impedance characteristics of the first embodiment of FIG. As can be seen from FIG. 3, by largely defining the ratio W1 / W2, the main propagation wave at the electrode finger crossing portion W3 is LSAW and the main propagation wave at the electrode finger non-crossing opening is SSBW. The unwanted wave coupling is reduced, and the conventional SAW resonator shown in FIG.
Unwanted spurious generated between the resonance frequency and the anti-resonance frequency of the resonator is reduced. It should be noted that this unnecessary spurious does not occur when the W1 / W2 ratio is 14 or more.
I learned from the experiment. Similar results were obtained with the surface acoustic wave resonator shown in FIG. Also, with the same electrode configuration, L
It was found that in the resonator formed on the iNbO 3 substrate, the above-mentioned unnecessary spurious was not generated, which was a phenomenon peculiar to SSBW.
【００１０】図４は、本発明の第３の実施例の２段ＩＤ
Ｔ型弾性表面波共振子の平面図であり、この弾性表面波
共振子は、第２の実施例の２段ＩＤＴ型弾性表面波共振
子の電極指非交差開口部Ｗ２とバスバー部分４との間
に、吸音剤５を塗布したものである。この実施例によれ
ば、電極指非交差開口部に発生するＳＳＢＷを吸音剤に
よって吸収することができるので、第１の実施例および
第２の実施例と同様に、ＬＳＡＷとＳＳＢＷとの不要波
の結合を低減させることができ、同等の効果が得られ
た。FIG. 4 shows a two-stage ID according to the third embodiment of the present invention.
It is a plan view of a T-type surface acoustic wave resonator, and this surface acoustic wave resonator has a structure in which the electrode finger non-intersecting opening W2 and the bus bar portion 4 of the two-stage IDT type surface acoustic wave resonator of the second embodiment are formed. The sound absorbing agent 5 is applied between them. According to this embodiment, the SSBW generated in the electrode finger non-intersecting openings can be absorbed by the sound absorbing agent. Therefore, as in the first and second embodiments, the unwanted waves of the LSAW and SSBW are absorbed. It was possible to reduce the binding, and the same effect was obtained.
【００１１】図５、６は、本発明の第４の実施例であ
り、実施例１および実施例２の弾性表面波共振子を組み
合わせた弾性表面波共振子型フィルタについて示したも
のである。図５は、この弾性表面波共振子型フィルタの
回路構成図であり、共振周波数のそれぞれ違う弾性表面
波共振子６、７、８、９、１０、１１と、この共振子を
調整するインダクタパターンＬ１、Ｌ２、Ｌ３、Ｌ４、
Ｌ５で構成されている。図に示すように、インダクタパ
ターンＬ１，Ｌ２および弾性表面波共振子４，９，１１
ならびにインダクタパターンＬ５が直列に接続され、イ
ンダクタパターンＬ１とインダクタパタ−ンＬ２の接続
点に、弾性表面波共振子４が、弾性表面波共振子４と弾
性表面波共振子９の接続点および弾性表面波共振子９と
弾性表面波共振子１１の接続点に、それぞれ弾性表面波
共振子８とインダクタパターンＬ３の直列回路および弾
性表面波共振子１０とインダクタパターンＬ４の直列回
路が並列に接続されて、弾性表面波共振子型フィルタを
構成している。インダクタパターンは、アルミナ基板上
に銅でスパイラル状に形成されたものであり、弾性表面
波共振子と２５μφのアルミニウムワイヤーで接続され
ている。尚、このワイヤーは、材料としてアルミニウム
（Ａｌ）を使用したが、アルミニウムのほか金（Ａｕ）
等であっても構わない。FIGS. 5 and 6 show a fourth embodiment of the present invention, showing a surface acoustic wave resonator type filter in which the surface acoustic wave resonators of the first and second embodiments are combined. FIG. 5 is a circuit configuration diagram of the surface acoustic wave resonator type filter, which includes surface acoustic wave resonators 6, 7, 8, 9, 10, 11 having different resonance frequencies and an inductor pattern for adjusting the resonators. L1, L2, L3, L4,
It is composed of L5. As shown in the figure, the inductor patterns L1 and L2 and the surface acoustic wave resonators 4, 9 and 11
In addition, the inductor pattern L5 is connected in series, and the surface acoustic wave resonator 4 is provided at the connection point between the inductor pattern L1 and the inductor pattern L2, and the connection point between the surface acoustic wave resonator 4 and the surface acoustic wave resonator 9 and the elasticity. A series circuit of the surface acoustic wave resonator 8 and the inductor pattern L3 and a series circuit of the surface acoustic wave resonator 10 and the inductor pattern L4 are connected in parallel to the connection points of the surface acoustic wave resonator 9 and the surface acoustic wave resonator 11, respectively. Thus forming a surface acoustic wave resonator type filter. The inductor pattern is spirally formed of copper on an alumina substrate, and is connected to the surface acoustic wave resonator with a 25 μφ aluminum wire. In addition, although aluminum (Al) was used as a material for this wire, in addition to aluminum, gold (Au) was used.
Etc. may be used.
【００１２】図６は、図５の回路構成に基づいた弾性表
面波共振子型フィルタの周波数特性を示したものであ
る。実線で示した周波数曲線は本発明の弾性表面波共振
子を組み合わせたフィルタに関する特性を示し、破線で
示した周波数特性は、従来の弾性表面波共振子を組み合
わせたフィルタに関する特性を示す。従来例では、弾性
表面波共振子単体特性で、共振周波数と***振周波数と
の間で不要スプリアスが発生するため、フィルタ特性に
おいても、通過域で不要スプリアスが生じ、損失を大き
く劣化させている。しかしながら実線で示した、電極指
の開口長Ｗ１と電極指非交差開口部Ｗ２の比を１４以上
（Ｗ１／Ｗ２≧１４）に規定した、本発明の弾性表面波
共振子を組み合わせることで、フィルタ特性の通過域の
不要スプリアスが発生せず、良好なフィルタの周波数特
性が実現可能となった。FIG. 6 shows frequency characteristics of a surface acoustic wave resonator type filter based on the circuit configuration of FIG. The frequency curve shown by the solid line shows the characteristic relating to the filter in which the surface acoustic wave resonator of the present invention is combined, and the frequency characteristic shown by the broken line shows the characteristic relating to the filter combining the conventional surface acoustic wave resonator. In the conventional example, in the surface acoustic wave resonator alone characteristic, unnecessary spurious is generated between the resonance frequency and the anti-resonant frequency, and therefore in the filter characteristic, unnecessary spurious is also generated in the pass band, which greatly deteriorates the loss. . However, by combining the surface acoustic wave resonator of the present invention in which the ratio between the opening length W1 of the electrode fingers and the non-intersecting opening W2 of the electrode fingers shown by the solid line is set to 14 or more (W1 / W2 ≧ 14), a filter is obtained. Unnecessary spurious in the pass band of the characteristics did not occur, and good frequency characteristics of the filter could be realized.
【００１３】図７および図８は、本発明の第５の実施例
を示し、図７は、第５の実施例の弾性表面波フィルタの
平面図を示したものである。本実施例では、３６度回転
Ｙ軸切断Ｘ軸伝搬のタンタル酸リチウム（ＬｉＴａ
Ｏ3）からなる圧電性基板１の上に、入力すだれ状電極
（ＩＤＴ）１２と出力ＩＤＴ１３が交互に配置されてお
り、入出力ＩＤＴ１２、１３の個数は、入力ＩＤＴ１２
は２個、出力ＩＤＴ１３は３個の多電極型構成となって
いる。入力ＩＤＴ１２、および出力ＩＤＴ１３はそれぞ
れ、電極指３から構成される。伝搬路上に形成されたこ
の電極指３とスペース部分は、共に等しくなっている。
また、入、出力ＩＤＴ１２、１３の間は、接地用電極パ
ターン１４が形成され、電極指３の形成周期と同間隔
で、しかも電極指３より大きな幅で隣接して形成されて
いる。この多電極型弾性表面波フィルタの中心周波数は
８８０ＭＨｚであり、入出力ＩＤＴ１２，１３の開口長
Ｗ１は１００μｍであり、電極指３の電極指非交差開口
部Ｗ２は５μｍに設定され、電極指の開口長Ｗ１と電極
指非交差開口部Ｗ２の比（Ｗ１／Ｗ２）を２０としてい
る。また電極指３の電極線幅およびスペース部分の幅は
共に１．２μｍとされ、接地用電極パターン１４の幅は
５μｍに設定されている。さらに、電極材料には、アル
ミニウム−チタン合金（Ａｌ−Ｔｉ合金）を用いてＤＣ
マグネトロンスパッタ法により電極膜厚を１００ｎｍに
成膜している。FIGS. 7 and 8 show a fifth embodiment of the present invention, and FIG. 7 shows a plan view of a surface acoustic wave filter of the fifth embodiment. In this embodiment, 36 degrees rotation Y-axis cutting X-axis propagation lithium tantalate (LiTa) is used.
Input interdigital transducers (IDTs) 12 and output IDTs 13 are alternately arranged on a piezoelectric substrate 1 made of O 3 ), and the number of input / output IDTs 12 and 13 is equal to that of the input IDTs 12.
2 and the output IDT 13 have a multi-electrode structure of 3. The input IDT 12 and the output IDT 13 are each composed of the electrode finger 3. The electrode finger 3 formed on the propagation path and the space portion are both equal.
A grounding electrode pattern 14 is formed between the input and output IDTs 12 and 13, and is formed adjacent to each other at the same interval as the electrode finger 3 forming period and with a width larger than the electrode finger 3. The center frequency of this multi-electrode surface acoustic wave filter is 880 MHz, the opening length W1 of the input / output IDTs 12 and 13 is 100 μm, the electrode finger non-intersecting opening W2 of the electrode finger 3 is set to 5 μm, and The ratio (W1 / W2) between the opening length W1 and the electrode finger non-intersecting opening W2 is set to 20. The electrode line width of the electrode finger 3 and the width of the space portion are both 1.2 μm, and the width of the ground electrode pattern 14 is set to 5 μm. Furthermore, an aluminum-titanium alloy (Al-Ti alloy) is used as the electrode material for DC.
The electrode film thickness is formed to 100 nm by the magnetron sputtering method.
【００１４】図８は、図７の多電極型弾性表面波フィル
タの周波数特性を示したものであり、実線は本発明のフ
ィルタの曲線を示し、破線は従来のフィルタの曲線を示
す。本発明においては、ＬＳＡＷと、ＳＳＢＷとの不要
波の結合を低減させるため、入出力ＩＤＴ１２、１３の
開口長Ｗ１と電極指非交差開口部Ｗ２の比（Ｗ１／Ｗ
２）を１４以上となるように考慮することで、従来技術
の周波数特性に比べ、過域での不要なうねりが緩和され
る。FIG. 8 shows the frequency characteristics of the multi-electrode surface acoustic wave filter of FIG. 7, the solid line shows the curve of the filter of the present invention, and the broken line shows the curve of the conventional filter. In the present invention, in order to reduce the coupling of unwanted waves between LSAW and SSBW, the ratio of the aperture length W1 of the input / output IDTs 12 and 13 to the electrode finger non-intersecting aperture W2 (W1 / W
By considering 2) to be 14 or more, unnecessary undulations in the overrange are alleviated as compared with the frequency characteristics of the prior art.
【００１５】また、図４の本発明第３の実施例と同様
に、電極指非交差開口部Ｗ２とバスバー部分４との間に
吸音剤５を塗布した構成としても、本発明の第５の実施
例と同様に、ＬＳＡＷと、ＳＳＢＷとの不要波の結合を
低減でき、同等の効果が得られた。Further, as in the case of the third embodiment of the present invention shown in FIG. 4, even if the sound absorbing agent 5 is applied between the electrode finger non-intersecting openings W2 and the bus bar portion 4, the fifth embodiment of the present invention will be described. Similar to the embodiment, the coupling of unwanted waves between LSAW and SSBW can be reduced, and the same effect can be obtained.
【００１６】上述のように、本発明においては、圧電性
基板はＬＳＡＷとＳＳＢＷが主伝搬波動となるタンタル
酸リチウム（ＬｉＴａＯ3）を用いたが、タンタル酸リ
チウムに限らず、電極指の開口部と電極指非交差開口部
で、違うモ−ドの発生する可能性のあるニオブ酸リチウ
ム（ＬｉＮｂＯ3）、あるいは水晶基板であっても良
い。さらに、電極材料はアルミニウム−チタン合金（Ａ
ｌ−Ｔｉ合金）に限らず、他のアルミニウム系合金であ
っても良い。As described above, in the present invention, the piezoelectric substrate is made of lithium tantalate (LiTaO 3 ) whose main propagation waves are LSAW and SSBW. It is also possible to use lithium niobate (LiNbO 3 ) or a quartz substrate which may generate different modes in the non-intersecting openings of the electrode fingers. Further, the electrode material is aluminum-titanium alloy (A
However, other aluminum-based alloys may be used.
【００１７】一般に、弾性表面波共振子を含む弾性表面
波フィルタは、電圧を印加して基板に機械的振動を生じ
させるので、余分な慣性的負荷が加わるのは好ましくな
い。このため、導電性良好で軽い材料、たとえばアルミ
ニウムあるいはアルミニウム合金で電極を形成すること
が好ましい。さらに、機械振動を生じる電極指３は、耐
マイグレーション性が重要であるので、導電性は多少低
いが、耐マイグレーション性の良好なアルミニウム−チ
タン合金（Ａｌ−Ｔｉ合金）を選定した。また、電極指
３の形成には、電極幅に高い寸法精度が要求されるの
で、湿式化学エッチングに代わり、塩化硼素（ＢＣ
ｌ3）、ＣＦ4ガスを用いた反応性ドライエッチング（Ｒ
ＩＥ）技術を用いた。Generally, in a surface acoustic wave filter including a surface acoustic wave resonator, a voltage is applied to cause mechanical vibration in the substrate, and it is not preferable to apply an extra inertial load. Therefore, it is preferable to form the electrode with a material having good conductivity and light weight, for example, aluminum or aluminum alloy. Furthermore, since the migration resistance is important for the electrode fingers 3 that generate mechanical vibration, an aluminum-titanium alloy (Al-Ti alloy) having good conductivity but low conductivity was selected. In addition, since high dimensional accuracy is required for the electrode width to form the electrode fingers 3, instead of wet chemical etching, boron chloride (BC
l 3 ), reactive dry etching using CF 4 gas (R
IE) technology was used.
【００１８】図９は、本発明の弾性表面波共振子型フィ
ルタを用いて構成した、移動無線機システムのアンテナ
分波器の構成を示す図である。この分波器の送信フィル
タ１５および受信フィルタ１６に、弾性表面波共振子型
フィルタを用いた。送信フィルタ１５および受信フィル
タ１６は、それぞれ分岐回路１７を介してアンテナ１８
と接続されている。移動無線機システムに用いる送信フ
ィルタ１５および受信フィルタ１６は、耐電力性を必要
とするだけでなく、８００〜９００ＭＨｚと高周波であ
るので弾性表面波共振子型フィルタを構成する入出力Ｉ
ＤＴの電極指が１μｍ程度と微細となる。又、フィルタ
特性として非常に低損失かつ急峻なフィルタの肩特性を
必要とし、組み合わせる共振子のインピーダンス特性が
非常に重要である。本発明の弾性表面波共振子を用いる
ことで、弾性表面波共振子のインピーダンス特性におい
て、***振周波数と共振周波数の間での不要スプリアス
が低減でき、良好なフィルタ特性が提供できる。また、
入出力ＩＤＴを持つ弾性表面波フィルタでも、不要な伝
搬波動の結合が低減でき通過域特性の良好な弾性表面波
フィルタが提供できる。FIG. 9 is a diagram showing a configuration of an antenna duplexer of a mobile radio system, which is constructed by using the surface acoustic wave resonator type filter of the present invention. A surface acoustic wave resonator type filter was used for the transmission filter 15 and the reception filter 16 of this duplexer. The transmission filter 15 and the reception filter 16 each include an antenna 18 via a branch circuit 17.
Connected with. The transmission filter 15 and the reception filter 16 used in the mobile radio system not only need power resistance but also have a high frequency of 800 to 900 MHz, so that the input / output I constituting the surface acoustic wave resonator type filter is used.
The electrode finger of DT is as fine as about 1 μm. Further, as filter characteristics, very low loss and steep filter shoulder characteristics are required, and impedance characteristics of a resonator to be combined are very important. By using the surface acoustic wave resonator of the present invention, in the impedance characteristic of the surface acoustic wave resonator, unnecessary spurious between the antiresonance frequency and the resonance frequency can be reduced, and good filter characteristics can be provided. Also,
Even with a surface acoustic wave filter having an input / output IDT, it is possible to provide a surface acoustic wave filter that can reduce unnecessary coupling of propagating waves and have excellent pass band characteristics.
【００１９】尚、本発明は、移動無線機システムに限ら
ず、ＶＴＲまたはＣＡＴＶ用コンバ−タならびに衛星放
送用受信機システム等に用いる弾性表面波共振子や弾性
表面波共振子型フィルタ、さらに一般の弾性表面波フィ
ルタにおいても有効な手段であることはいうまでもな
い。The present invention is not limited to mobile radio systems, but is also applicable to surface acoustic wave resonators and surface acoustic wave resonator type filters used in VTR or CATV converters, satellite broadcasting receiver systems, etc. It goes without saying that it is also an effective means in the surface acoustic wave filter of.
【００２０】更に、本発明は、共振子の電極構成とし
て、１ポートのＩＤＴ型弾性表面波共振子を取り上げた
が、ＩＤＴの外側に、反射電極を形成したキャビティ構
成のＩＤＴ型弾性表面波共振子、１チップ内に電気的に
独立した２つの弾性表面波共振子を形成した多重モード
構成のＩＤＴ型弾性表面波共振子、入出力ＩＤＴを２つ
持つ２ポート型構成のＩＤＴ型弾性表面波共振子等全て
の弾性表面波共振子構成においても有効な手段であるこ
とは、いうまでもない。本発明においては、電極指の開
口長Ｗ１とＩＤＴ電極の電極指非交差部Ｗ２の比を１４
以上（Ｗ１／Ｗ２≧１４）とするほど、つまり電極指非
交差部Ｗ２が小さいほど、電極指非交差部分で発生する
ＳＳＢＷの波の強度レベルを低減し、モ−ド結合と見ら
れる不要スプリアスを低減できる。Further, although the present invention takes up a 1-port IDT type surface acoustic wave resonator as the electrode configuration of the resonator, the IDT type surface acoustic wave resonance of the cavity configuration in which the reflection electrode is formed outside the IDT. IDT type surface acoustic wave resonator having a multi-mode structure in which two electrically independent surface acoustic wave resonators are formed in one chip, and a two-port type IDT type surface acoustic wave having two input / output IDTs. It goes without saying that it is also an effective means in the configuration of all surface acoustic wave resonators such as a resonator. In the present invention, the ratio of the opening length W1 of the electrode finger to the electrode finger non-intersection portion W2 of the IDT electrode is set to 14
The more the above (W1 / W2 ≧ 14), that is, the smaller the electrode finger non-intersecting portion W2, the lower the intensity level of the SSBW wave generated at the electrode finger non-intersecting portion, and unnecessary spurious that is considered to be mode coupling. Can be reduced.
【００２１】[0021]
【発明の効果】本発明によれば、圧電性基板上に形成さ
れた弾性表面波共振子および弾性表面波共振子を組み合
わせた弾性表面波共振子型フィルタならびに入出力ＩＤ
Ｔを持つ弾性表面波フィルタにおいて、ＩＤＴの開口長
Ｗ１と、電極指非交差部Ｗ２の比を１４以上と規定する
こと、またはＩＤＴの電極指非交差部とバスバー部分
を、吸音材で塗布することで、インピーダンス−周波数
特性の良好な弾性表面波共振子および弾性表面波共振子
型フィルタならびに弾性表面波フィルタを提供できる。According to the present invention, a surface acoustic wave resonator formed on a piezoelectric substrate, a surface acoustic wave resonator type filter combining the surface acoustic wave resonators, and an input / output ID.
In the surface acoustic wave filter having T, the ratio of the opening length W1 of the IDT to the electrode finger non-intersection portion W2 is specified to be 14 or more, or the electrode finger non-intersection portion of the IDT and the bus bar portion are coated with a sound absorbing material. As a result, a surface acoustic wave resonator, a surface acoustic wave resonator type filter, and a surface acoustic wave filter having excellent impedance-frequency characteristics can be provided.
【図１】本発明第１の実施例の平面図。FIG. 1 is a plan view of a first embodiment of the present invention.
【図２】本発明第１の実施例のインピ−ダンス特性。FIG. 2 is an impedance characteristic of the first embodiment of the present invention.
【図３】本発明第２の実施例の平面図。FIG. 3 is a plan view of a second embodiment of the present invention.
【図４】本発明第３の実施例の平面図。FIG. 4 is a plan view of a third embodiment of the present invention.
【図５】本発明第４の実施例の回路構成図。FIG. 5 is a circuit configuration diagram of a fourth embodiment of the present invention.
【図６】本発明第４の実施例の周波数特性。FIG. 6 is a frequency characteristic of the fourth embodiment of the present invention.
【図７】本発明第５の実施例の平面図。FIG. 7 is a plan view of the fifth embodiment of the present invention.
【図８】本発明第５の実施例の周波数特性。FIG. 8 shows frequency characteristics of the fifth embodiment of the present invention.
【図９】本発明を用いた移動無線機のアンテナ分波器。FIG. 9 is an antenna duplexer of a mobile wireless device using the present invention.
【図１０】従来技術のインピ−ダンス特性。FIG. 10 shows the impedance characteristics of the prior art.
１ 圧電性基板 ２ ボンディングパッド ３ 電極指 ４ バスバ− ５ 吸音剤 ６〜１１ 弾性表面波共振子 １２ 入力ＩＤＴ １３ 出力ＩＤＴ １４ 接地用電極パターン １５ 送信フィルタ １６ 受信フィルタ １７ 分岐回路 １８ アンテナ 1 Piezoelectric Substrate 2 Bonding Pad 3 Electrode Finger 4 Bus Bar 5 Sound Absorber 6-11 Surface Acoustic Wave Resonator 12 Input IDT 13 Output IDT 14 Grounding Electrode Pattern 15 Transmit Filter 16 Receive Filter 17 Branch Circuit 18 Antenna
Claims (18)
電極を有する弾性表面波共振子、もしくは、圧電性基板
上に金属膜からなるすだれ状電極を有する弾性表面波共
振子を複数個バスバ−により直列に接続した多段型弾性
表面波共振子において、 前記共振子の開口長Ｗ１と共振子を構成するすだれ状電
極の電極指非交差部Ｗ２の比を１４以上（Ｗ１／Ｗ２≧
１４）としたことを特徴とする弾性表面波共振子。1. A surface acoustic wave resonator having a comb-shaped electrode made of a metal film on a piezoelectric substrate, or a plurality of surface acoustic wave resonators having a comb-shaped electrode made of a metal film on a piezoelectric substrate. In the multi-stage surface acoustic wave resonator connected in series by-, the ratio of the aperture length W1 of the resonator to the electrode finger non-intersection portion W2 of the interdigital electrode constituting the resonator is 14 or more (W1 / W2 ≧
14) A surface acoustic wave resonator characterized in that
電性基板が、バルク波（Ｓｕｒｆａｃｅ Ｓｋｉｍｍｉ
ｎｇ Ｂｕｌｋ Ｗａｖｅ；ＳＳＢＷ）もしくは疑似弾
性表面波（Ｌｅａｋｙ Ｓｕｒｆａｃｅ Ａｃｏｕｓｔ
ｉｃ ；ＷａｖｅＬＳＡＷ）を励振するタンタル酸リチ
ウム単結晶基板（ＬｉＴａＯ3）またはニオブ酸リチウ
ム単結晶基板（ＬｉＮｂＯ3）を用いたものである、請
求項１に記載の弾性表面波共振子。2. A piezoelectric substrate having a comb-shaped electrode made of a metal film is a bulk wave (Surface Skimmi).
ng Bulk Wave; SSBW) or pseudo surface acoustic wave (Leaky Surface Acoustic)
The surface acoustic wave resonator according to claim 1, wherein a lithium tantalate single crystal substrate (LiTaO 3 ) or a lithium niobate single crystal substrate (LiNbO 3 ) that excites ic; Wave LSAW) is used.
電極を有する弾性表面波共振子、もしくは、圧電性基板
上に金属膜からなるすだれ状電極を有する弾性表面波共
振子を複数個バスバーにより直列に接続した多段型弾性
表面波共振子において、 前記共振子を構成するすだれ状電極の電極指非交差部と
バスバー部分を吸音材で塗布したことを特徴とする弾性
表面波共振子。3. A bus bar comprising a surface acoustic wave resonator having a comb-shaped electrode made of a metal film on a piezoelectric substrate, or a plurality of surface acoustic wave resonators having a comb-shaped electrode made of a metal film on a piezoelectric substrate. In a multi-stage surface acoustic wave resonator connected in series by means of the above, the surface acoustic wave resonator is characterized in that the electrode finger non-intersection portion and the bus bar portion of the interdigital transducer which constitutes the resonator are coated with a sound absorbing material.
電性基板が、バルク波（Ｓｕｒｆａｃｅ Ｓｋｉｍｍｉ
ｎｇ Ｂｕｌｋ Ｗａｖｅ；ＳＳＢＷ）もしくは疑似弾
性表面波（Ｌｅａｋｙ Ｓｕｒｆａｃｅ Ａｃｏｕｓｔ
ｉｃ ；ＷａｖｅＬＳＡＷ）を励振するタンタル酸リチ
ウム単結晶基板（ＬｉＴａＯ3）またはニオブ酸リチウ
ム単結晶基板（ＬｉＮｂＯ3）を用いたものである、請
求項３に記載の弾性表面波共振子。4. A piezoelectric substrate having a comb-shaped electrode made of a metal film, wherein a bulk wave (Surface Skimmi) is used.
ng Bulk Wave; SSBW) or pseudo surface acoustic wave (Leaky Surface Acoustic)
The surface acoustic wave resonator according to claim 3, wherein a lithium tantalate single crystal substrate (LiTaO 3 ) or a lithium niobate single crystal substrate (LiNbO 3 ) that excites ic; Wave LSAW) is used.
性表面波を送受する１個以上の入力すだれ状電極と出力
すだれ状電極を同一伝搬路上に配設した弾性表面波フィ
ルタまたは多電極型弾性表面波フィルタにおいて、 該弾性表面波フィルタまたは該多電極型弾性表面波フィ
ルタの入力すだれ状電極および出力すだれ状電極の開口
長Ｗ１と入力すだれ状電極および出力すだれ状電極の電
極指非交差部Ｗ２の比を１４以上（Ｗ１／Ｗ２≧１４）
としたことを特徴とする弾性表面波フィルタまたは多電
極型弾性表面波フィルタ。5. A surface acoustic wave filter or a multi-electrode type in which one or more input interdigital electrodes and output interdigital electrodes, which are made of a metal film and which transmit and receive surface acoustic waves to each other, are arranged on the same propagation path on a piezoelectric substrate. In the surface acoustic wave filter, the opening length W1 of the input interdigital electrode and the output interdigital electrode of the surface acoustic wave filter or the multi-electrode surface acoustic wave filter and the electrode finger non-intersecting portion of the input interdigital electrode and the output interdigital electrode W2 ratio is 14 or more (W1 / W2 ≧ 14)
A surface acoustic wave filter or a multi-electrode surface acoustic wave filter characterized in that.
電性基板が、バルク波（Ｓｕｒｆａｃｅ Ｓｋｉｍｍｉ
ｎｇ Ｂｕｌｋ Ｗａｖｅ；ＳＳＢＷ）もしくは疑似弾
性表面波（Ｌｅａｋｙ Ｓｕｒｆａｃｅ Ａｃｏｕｓｔ
ｉｃ Ｗａｖｅ；ＬＳＡＷ）を励振するタンタル酸リチ
ウム単結晶基板（ＬｉＴａＯ3）またはニオブ酸リチウ
ム単結晶基板（ＬｉＮｂＯ3）を用いたものである、請
求項５に記載の弾性表面波共振子型フィルタ。6. A piezoelectric substrate having a comb-shaped electrode made of a metal film, a bulk wave (Surface Skimmi)
ng Bulk Wave; SSBW) or pseudo surface acoustic wave (Leaky Surface Acoustic)
The surface acoustic wave resonator type filter according to claim 5, wherein a lithium tantalate single crystal substrate (LiTaO 3 ) or a lithium niobate single crystal substrate (LiNbO 3 ) that excites ic Wave (LSAW) is used.
性表面波を送受する１個以上の入力すだれ状電極と出力
すだれ状電極を同一伝搬路上に配設した弾性表面波フィ
ルタまたは多電極型弾性表面波フィルタにおいて、 該弾性表面波フィルタまたは該多電極型弾性表面波フィ
ルタの入力すだれ状電極および出力すだれ状電極の電極
指非交差部とバスバー部分を吸音材で塗布したことを特
徴とする弾性表面波フィルタ、または多電極型弾性表面
波フィルタ。7. A surface acoustic wave filter or a multi-electrode type in which one or more input interdigital transducers and output interdigital transducers, which are made of a metal film and which transmit and receive surface acoustic waves to each other, are arranged on the same propagation path on a piezoelectric substrate. In the surface acoustic wave filter, the input finger non-intersecting portion and the bus bar portion of the input interdigital electrode and the output interdigital electrode of the surface acoustic wave filter or the multi-electrode surface acoustic wave filter are coated with a sound absorbing material. Surface acoustic wave filter or multi-electrode surface acoustic wave filter.
電性基板が、バルク波（Ｓｕｒｆａｃｅ Ｓｋｉｍｍｉ
ｎｇ Ｂｕｌｋ Ｗａｖｅ；ＳＳＢＷ）もしくは疑似弾
性表面波（Ｌｅａｋｙ Ｓｕｒｆａｃｅ Ａｃｏｕｓｔ
ｉｃ Ｗａｖｅ；ＬＳＡＷ）を励振するタンタル酸リチ
ウム単結晶基板（ＬｉＴａＯ3）またはニオブ酸リチウ
ム単結晶基板（ＬｉＮｂＯ3）を用いたものである、請
求項７に記載の弾性表面波共振子型フィルタ。8. A piezoelectric substrate having a comb-shaped electrode made of a metal film, a bulk wave (Surface Skimmi)
ng Bulk Wave; SSBW) or pseudo surface acoustic wave (Leaky Surface Acoustic)
The surface acoustic wave resonator filter according to claim 7, wherein a lithium tantalate single crystal substrate (LiTaO 3 ) or a lithium niobate single crystal substrate (LiNbO 3 ) which excites ic Wave; LSAW) is used.
電極を有する弾性表面波共振子、もしくは、圧電性基板
上に金属膜からなるすだれ状電極を有する弾性表面波共
振子を複数個バスバーにより直列に接続した多段型弾性
表面波共振子であって、前記共振子の開口長Ｗ１と共振
子を構成するすだれ状電極の電極指非交差部Ｗ２の比を
１４以上（Ｗ１／Ｗ２≧１４）とした弾性表面波共振子
を用い、共振周波数の違う共振子を、それぞれインダク
タを介して接続したことを特徴とした弾性表面波共振子
型フィルタ。9. A bus bar comprising a surface acoustic wave resonator having a comb-shaped electrode made of a metal film on a piezoelectric substrate, or a plurality of surface acoustic wave resonators having a comb-shaped electrode made of a metal film on a piezoelectric substrate. In the multi-stage surface acoustic wave resonator connected in series by, the ratio of the opening length W1 of the resonator to the electrode finger non-intersection portion W2 of the interdigital electrode constituting the resonator is 14 or more (W1 / W2 ≧ 14). The surface acoustic wave resonator type filter characterized in that resonators having different resonance frequencies are connected via inductors.
圧電性基板が、バルク波（Ｓｕｒｆａｃｅ Ｓｋｉｍｍ
ｉｎｇ Ｂｕｌｋ Ｗａｖｅ；ＳＳＢＷ）もしくは疑似
弾性表面波（Ｌｅａｋｙ Ｓｕｒｆａｃｅ Ａｃｏｕｓ
ｔｉｃ Ｗａｖｅ；ＬＳＡＷ）を励振するタンタル酸リ
チウム単結晶基板（ＬｉＴａＯ3）またはニオブ酸リチ
ウム単結晶基板（ＬｉＮｂＯ3）を用いたものである、
請求項９に記載の弾性表面波共振子型フィルタ。10. A piezoelectric substrate having a comb-shaped electrode made of a metal film, a bulk wave (Surface Skimm)
ing Bulk Wave; SSBW) or pseudo surface acoustic wave (Leaky Surface Acoustic)
a lithium tantalate single crystal substrate (LiTaO 3 ) or a lithium niobate single crystal substrate (LiNbO 3 ) that excites a TIC Wave; LSAW) is used.
The surface acoustic wave resonator type filter according to claim 9.
状電極を有する弾性表面波共振子、もしくは、圧電性基
板上に金属膜からなるすだれ状電極を有する弾性表面波
共振子を複数個バスバーにより直列に接続した多段型弾
性表面波共振子であって、前記共振子を構成するすだれ
状電極の電極指非交差部とバスバー部分を吸音材で塗布
した弾性表面波共振子を用い、共振周波数の違う共振子
を、それぞれインダクタを介して接続したことを特徴と
した弾性表面波共振子型フィルタ。11. A bus bar comprising a surface acoustic wave resonator having a comb-shaped electrode made of a metal film on a piezoelectric substrate, or a plurality of surface acoustic wave resonators having a comb-shaped electrode made of a metal film on a piezoelectric substrate. Is a multi-stage surface acoustic wave resonator connected in series by means of a surface acoustic wave resonator in which the electrode finger non-intersection portion of the interdigital transducer and the bus bar portion forming the resonator are coated with a sound absorbing material. A surface acoustic wave resonator type filter characterized by connecting different resonators via inductors.
圧電性基板が、バルク波（Ｓｕｒｆａｃｅ Ｓｋｉｍｍ
ｉｎｇ Ｂｕｌｋ Ｗａｖｅ；ＳＳＢＷ）もしくは疑似
弾性表面波（Ｌｅａｋｙ Ｓｕｒｆａｃｅ Ａｃｏｕｓ
ｔｉｃ Ｗａｖｅ；ＬＳＡＷ）を励振するタンタル酸リ
チウム単結晶基板（ＬｉＴａＯ3）またはニオブ酸リチ
ウム単結晶基板（ＬｉＮｂＯ3）を用いたものである、
請求項１１に記載の弾性表面波共振子型フィルタ。12. A piezoelectric substrate having a comb-shaped electrode made of a metal film, wherein a bulk wave (Surface Skimm) is used.
ing Bulk Wave; SSBW) or pseudo surface acoustic wave (Leaky Surface Acoustic)
a lithium tantalate single crystal substrate (LiTaO 3 ) or a lithium niobate single crystal substrate (LiNbO 3 ) that excites a TIC Wave; LSAW) is used.
The surface acoustic wave resonator type filter according to claim 11.
状電極を有する弾性表面波共振子、もしくは、圧電性基
板上に金属膜からなるすだれ状電極を有する弾性表面波
共振子を複数個バスバーにより直列に接続した多段型弾
性表面波共振子であって、前記共振子の開口長Ｗ１と共
振子を構成するすだれ状電極の電極指非交差部Ｗ２の比
を１４以上（Ｗ１／Ｗ２≧１４）とした弾性表面波共振
子を移動無線機の中間周波フィルタとして用いたことを
特徴とする移動無線機システム。13. A bus bar comprising a surface acoustic wave resonator having a comb-shaped electrode made of a metal film on a piezoelectric substrate, or a plurality of surface acoustic wave resonators having a comb-shaped electrode made of a metal film on a piezoelectric substrate. In the multi-stage surface acoustic wave resonator connected in series by, the ratio of the opening length W1 of the resonator to the electrode finger non-intersection portion W2 of the interdigital electrode constituting the resonator is 14 or more (W1 / W2 ≧ 14). (2) The surface acoustic wave resonator as described above is used as an intermediate frequency filter of a mobile radio device.
状電極を有する弾性表面波共振子、もしくは、圧電性基
板上に金属膜からなるすだれ状電極を有する弾性表面波
共振子を複数個バスバーにより直列に接続した多段型弾
性表面波共振子であって、前記共振子を構成するすだれ
状電極の電極指非交差部とバスバー部分を吸音材で塗布
した弾性表面波共振子を移動無線機の中間周波フィルタ
として用いたことを特徴とする移動無線機システム。14. A bus bar comprising a surface acoustic wave resonator having a comb-shaped electrode made of a metal film on a piezoelectric substrate, or a plurality of surface acoustic wave resonators having a comb-shaped electrode made of a metal film on a piezoelectric substrate. Is a multi-stage surface acoustic wave resonator connected in series by means of a surface acoustic wave resonator in which the electrode finger non-intersection portion of the interdigital transducer and the bus bar portion forming the resonator are coated with a sound absorbing material. A mobile radio system characterized by being used as an intermediate frequency filter.
弾性表面波を送受する１個以上の入力すだれ状電極と出
力すだれ状電極を同一伝搬路上に配設した弾性表面波フ
ィルタまたは多電極型弾性表面波フィルタであって、該
弾性表面波フィルタまたは該多電極型弾性表面波フィル
タの入力すだれ状電極および出力すだれ状電極の開口長
Ｗ１と入力すだれ状電極および出力すだれ状電極の電極
指非交差部Ｗ２の比を１４以上（Ｗ１／Ｗ２≧１４）と
した弾性表面波フィルタまたは多電極型弾性表面波フィ
ルタを移動無線機の中間周波フィルタとして用いたこと
を特徴とする移動無線機システム。15. A surface acoustic wave filter or a multi-electrode type in which one or more input interdigital transducers and output interdigital transducers formed of a metal film and transmitting and receiving surface acoustic waves to each other are arranged on the same propagation path on a piezoelectric substrate. A surface acoustic wave filter comprising: an input interdigital electrode and an output interdigital electrode of the surface acoustic wave filter or the multi-electrode surface acoustic wave filter; A mobile radio system, wherein a surface acoustic wave filter or a multi-electrode surface acoustic wave filter having a crossing W2 ratio of 14 or more (W1 / W2 ≧ 14) is used as an intermediate frequency filter of the mobile radio.
弾性表面波を送受する１個以上の入力すだれ状電極と出
力すだれ状電極を同一伝搬路上に配設した弾性表面波フ
ィルタまたは多電極型弾性表面波フィルタであって、該
弾性表面波フィルタまたは該多電極型弾性表面波フィル
タの入力すだれ状電極および出力すだれ状電極の電極指
非交差部とバスバー部分を吸音材で塗布した弾性表面波
フィルタまたは多電極型弾性表面波フィルタを移動無線
機の中間周波フィルタとして用いたことを特徴とする移
動無線機システム。16. A surface acoustic wave filter or a multi-electrode type in which one or more input interdigital transducers and output interdigital transducers that transmit and receive surface acoustic waves made of a metal film are arranged on the same propagation path on a piezoelectric substrate. A surface acoustic wave filter comprising a surface acoustic wave filter or a multi-electrode surface acoustic wave filter, wherein input electrode non-intersecting electrodes and output interdigital transducers of the interdigital electrode fingers and a bus bar portion are coated with a sound absorbing material. A mobile radio system in which a filter or a multi-electrode surface acoustic wave filter is used as an intermediate frequency filter of the mobile radio.
状電極を有する弾性表面波共振子、もしくは、圧電性基
板上に金属膜からなるすだれ状電極を有する弾性表面波
共振子を複数個バスバーにより直列に接続した多段型弾
性表面波共振子であって、前記共振子の開口長Ｗ１と共
振子を構成するすだれ状電極の電極指非交差部Ｗ２の比
を１４以上（Ｗ１／Ｗ２≧１４）とした弾性表面波共振
子を用い、共振周波数の違う共振子を、それぞれインダ
クタを介して接続したことを特徴とした弾性表面波共振
子型フィルタを移動無線機の中間周波フィルタとして用
いたことを特徴とする移動無線機システム。17. A bus bar comprising a surface acoustic wave resonator having a comb-shaped electrode made of a metal film on a piezoelectric substrate, or a plurality of surface acoustic wave resonators having a comb-shaped electrode made of a metal film on a piezoelectric substrate. In the multi-stage surface acoustic wave resonator connected in series by, the ratio of the opening length W1 of the resonator to the electrode finger non-intersection portion W2 of the interdigital electrode constituting the resonator is 14 or more (W1 / W2 ≧ 14). The surface acoustic wave resonator type filter, which is characterized in that resonators having different resonance frequencies are connected via inductors, is used as an intermediate frequency filter of a mobile radio device. Mobile radio system characterized by.
状電極を有する弾性表面波共振子、もしくは、圧電性基
板上に金属膜からなるすだれ状電極を有する弾性表面波
共振子を複数個バスバーにより直列に接続した多段型弾
性表面波共振子であって、前記共振子を構成するすだれ
状電極の電極指非交差部とバスバー部分を吸音材で塗布
した弾性表面波共振子を用い、共振周波数の違う共振子
を、それぞれインダクタを介して接続したことを特徴と
した弾性表面波共振子型フィルタを移動無線機の中間周
波フィルタとして用いたことを特徴とする移動無線機シ
ステム。18. A bus bar comprising a surface acoustic wave resonator having a comb-shaped electrode made of a metal film on a piezoelectric substrate, or a plurality of surface acoustic wave resonators having a comb-shaped electrode made of a metal film on a piezoelectric substrate. Is a multi-stage surface acoustic wave resonator connected in series by means of a surface acoustic wave resonator in which the electrode finger non-intersection portion of the interdigital transducer and the bus bar portion forming the resonator are coated with a sound absorbing material. A mobile radio system in which a surface acoustic wave resonator type filter characterized by connecting different resonators via inductors is used as an intermediate frequency filter of the mobile radio.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001793A JPH06232682A (en) | 1993-02-08 | 1993-02-08 | Surface acoustic wave resonator and surface acoustic wave filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001793A JPH06232682A (en) | 1993-02-08 | 1993-02-08 | Surface acoustic wave resonator and surface acoustic wave filter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06232682A true JPH06232682A (en) | 1994-08-19 |
Family
ID=12015337
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001793A Pending JPH06232682A (en) | 1993-02-08 | 1993-02-08 | Surface acoustic wave resonator and surface acoustic wave filter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06232682A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0993072A (en) * | 1995-09-26 | 1997-04-04 | Fujitsu Ltd | Surface acoustic wave filter |
| US6265808B1 (en) | 1998-11-24 | 2001-07-24 | Murata Manufacturing Co., Ltd. | Surface acoustic wave filter |
| US6292071B1 (en) | 1998-11-25 | 2001-09-18 | Murata Manufacturing, Co., Ltd. | Surface acoustic wave filter for improving flatness of a pass band and a method of manufacturing thereof |
| JP2004328196A (en) * | 2003-04-23 | 2004-11-18 | Fujitsu Media Device Kk | Surface acoustic wave device |
| US7215224B2 (en) | 2001-04-09 | 2007-05-08 | Murata Manufacturing Co., Ltd. | Surface acoustic wave filter, surface acoustic wave device and communication device |
| EP2009789A2 (en) | 2007-06-29 | 2008-12-31 | Nihon Dempa Kogyo Co., Ltd. | Damper on the busbars of a SAW filter |
| JP2009246943A (en) * | 2008-03-12 | 2009-10-22 | Seiko Epson Corp | Lamb-wave resonator and oscillator |
-
1993
- 1993-02-08 JP JP2001793A patent/JPH06232682A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0993072A (en) * | 1995-09-26 | 1997-04-04 | Fujitsu Ltd | Surface acoustic wave filter |
| US6265808B1 (en) | 1998-11-24 | 2001-07-24 | Murata Manufacturing Co., Ltd. | Surface acoustic wave filter |
| US6518861B2 (en) * | 1998-11-24 | 2003-02-11 | Murata Manufacturing Co., Ltd. | Surface acoustic wave filter formed with a ripple at the high frequency shoulder of the pass band |
| US6292071B1 (en) | 1998-11-25 | 2001-09-18 | Murata Manufacturing, Co., Ltd. | Surface acoustic wave filter for improving flatness of a pass band and a method of manufacturing thereof |
| US7215224B2 (en) | 2001-04-09 | 2007-05-08 | Murata Manufacturing Co., Ltd. | Surface acoustic wave filter, surface acoustic wave device and communication device |
| JP2004328196A (en) * | 2003-04-23 | 2004-11-18 | Fujitsu Media Device Kk | Surface acoustic wave device |
| EP2009789A2 (en) | 2007-06-29 | 2008-12-31 | Nihon Dempa Kogyo Co., Ltd. | Damper on the busbars of a SAW filter |
| JP2009016960A (en) * | 2007-06-29 | 2009-01-22 | Nippon Dempa Kogyo Co Ltd | Acoustic wave device |
| JP2009246943A (en) * | 2008-03-12 | 2009-10-22 | Seiko Epson Corp | Lamb-wave resonator and oscillator |
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