JP2004153416A

JP2004153416A - Balanced lamination strip line filter

Info

Publication number: JP2004153416A
Application number: JP2002314412A
Authority: JP
Inventors: Kenji Tagami; 健次田上
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2002-10-29
Filing date: 2002-10-29
Publication date: 2004-05-27

Abstract

<P>PROBLEM TO BE SOLVED: To provide a broadband balanced lamination strip line filter capable of reducing variations in an attenuation pole in a filter characteristic due to deviation in the lamination caused in a process of laminating a plurality of dielectric layers. <P>SOLUTION: In the balanced lamination strip line filter, first and third resonators 71, 73 are placed in sequentially layered first to third dielectric layers in parallel in a way that at least the respective parts are overlapped when viewed from the layered direction while sandwiching the second dielectric layer, second and fourth resonators 72, 74 are placed in parallel in a way that at least the respective parts are overlapped when viewed from the layered direction while sandwiching the second dielectric layer, the first and second resonators 71, 72 and the third and fourth resonators 73, 74 are placed in plane symmetry with respect to a plane configured by the lengthwise direction and the layered direction of the first to fourth resonators 71 to 74. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、例えば携帯電話や無線ＬＡＮ等の無線通信機器その他の各種通信機器等において使用される平衡型積層ストリップラインフィルタに関するものである。
【０００２】
【従来の技術】
近年、携帯電話機等の移動体通信機器等に使用されるフィルタは、移動体通信機器等の薄型化・小型化の要求に伴い、誘電体同軸型共振器を用いたフィルタから分布定数回路を共振器に用いた積層ストリップラインフィルタへと進展してきている。また、高周波増幅回路設計の観点からは、不平衡型回路は外部雑音などの影響を受け易いという問題があり、平衡型回路が採用されてきている。
【０００３】
そして、この平衡型回路に接続する従来の平衡型積層ストリップラインフィルタとして、特開平１１−３１７６０３号公報には、図８に透視斜視図および図９に断面図で示す構成のものが提案されている。
【０００４】
図８および図９において、１０は誘電体、１１〜１４は誘電体１０内に配置された第１〜第４の共振器である。第１および第２の共振器１１・１２は相互に電磁界結合されて第１の一対の共振器１５を構成し、第３および第４の共振器１３・１４は相互に電磁界結合されて第２の一対の共振器１６を構成し、さらに第１の一対の共振器１５と第２の一対の共振器１６が互いに対面して面対称に誘電体１０内に配置され、第１〜第４の共振器１１〜１４にはそれぞれ入力端子１８ａ・１８ｂおよび出力端子１９ａ・１９ｂが接続されて入力端子１８ａ・１８ｂで形成される平衡型の入力端子および出力端子１９ａ・１９ｂで形成される平衡型の出力端子を構成している。
【０００５】
また、さらに第１の一対の共振器１５と第２の一対の共振器１６間の電気壁位置に接地導体１７を配置する構成も提案されている。
【０００６】
また図８および図９に示す従来の平衡型積層ストリップラインフィルタの別な構成例を図６に透視斜視図および図７に断面図で示す。
【０００７】
図６および図７において、２０ａ〜２０ｆは誘電体層、２０は誘電体であり、誘電体２０は誘電体層２０ａ〜２０ｆが順次積層されて形成される。２１〜２４は誘電体２０内に配置された第１〜第４の共振器である。
【０００８】
第１および第２の共振器２１・２２は誘電体層２０ｅを挟んでそれぞれの少なくとも一部が重なるように対向して配されることによって相互に電磁界結合されて第１の一対の共振器２５を構成し、第３および第４の共振器２３・２４は誘電体層２０ｂを挟んでそれぞれの少なくとも一部が重なるように対向して配されることによって相互に電磁界結合されて第２の一対の共振器２６を構成し、さらに第１の一対の共振器２５と第２の一対の共振器２６が互いに対面して面対称に誘電体２０内に配置され、第１〜第４の共振器２１〜２４にはそれぞれ入力端子２８ａ・２８ｂおよび出力端子２９ａ・２９ｂが接続されて入力端子２８ａ・２８ｂで形成される平衡型の入力端子および出力端子２９ａ・２９ｂで形成される平衡型の出力端子を構成している。
【０００９】
また、さらに第１の一対の共振器２５と第２の一対の共振器２６間の電気壁位置に接地導体２７を配置する構成も提案されている。
【００１０】
そして、図６〜図９に示す従来の平衡型積層ストリップラインフィルタにおいて、第１の一対の共振器１５（２５）と第２の一対の共振器１６（２６）間に形成される電位零の電気壁によって外部雑音が相殺され、外部雑音に強い平衡型積層ストリップラインフィルタを実現していた。
【００１１】
【特許文献１】
特開平１１−３１７６０３号公報
【００１２】
【発明が解決しようとする課題】
しかしながら、このような従来の平衡型積層ストリップラインフィルタにおいては、図８および図９に示す構成の場合、第１および第２の共振器１１・１２と第３および第４の共振器１３・１４とがそれぞれ同一平面上に配されており、第１および第２の共振器１１・１２間と第３および第４の共振器１３・１４間で形成される電磁界結合はエッジ結合となり、大きな電磁界結合を実現できず、このため広帯域なフィルタ特性が実現できないという問題点があった。
【００１３】
そして、この問題を解決する方法として、図６に透視斜視図および図７に断面図で示す構成のように、第１および第２の共振器２１・２２を誘電体層２０ｅを挟んでそれぞれの少なくとも一部が重なるように対向して配するとともに、第３および第４の共振器２３・２４を誘電体層２０ｂを挟んでそれぞれの少なくとも一部が重なるように対向して配することによって、第１および第２の共振器２１・２２間と第３および第４の共振器２３・２４間で形成される電磁界結合はブロードサイド結合となり、大きな電磁界結合を実現でき、この結果、広帯域なフィルタ特性を実現することができるが、この場合は順次積層される誘電体層２０ａ〜２０ｆの積層ズレによって第１および第２の共振器２１・２２間と第３および第４の共振器２３・２４間で形成される電磁界結合のバランスが崩れ、このためフィルタ特性の減衰極が変動するという問題点があった。
【００１４】
本発明は上記問題点に鑑みて案出されたものであり、その目的は、平衡型積層ストリップラインフィルタにおいて、複数の誘電体層を積層する工程において発生する積層ずれによるフィルタ特性の減衰極の変動を低減することができる広帯域な平衡型積層ストリップラインフィルタを提供することにある。
【００１５】
【課題を解決するための手段】
本発明の平衡型積層ストリップラインフィルタは、第１の誘電体層と、前記第１の誘電体層の上に積層された第２の誘電体層と、前記第２の誘電体層の上に積層された第３の誘電体層と、前記第１の誘電体層の下面に配された第１の接地電極と、前記第１および第２の誘電体層の間に配された第１および第２の片端開放矩形状共振電極ならびに第１および第２の片端短絡矩形状共振電極と、前記第２および第３の誘電体層の間に配された第３および第４の片端開放矩形状共振電極ならびに第３および第４の片端短絡矩形状共振電極と、前記第３の誘電体層の上面に配された第２の接地電極とから成り、
前記第１〜第４の片端開放矩形状共振電極は略同一の形状を有し、前記第１および第３の片端開放矩形状共振電極は前記第２の誘電体層を挟んでそれぞれの少なくとも一部が積層方向から見て重なるように平行に配されるとともに、前記第２および第４の片端開放矩形状共振電極は前記第２の誘電体層を挟んでそれぞれの少なくとも一部が積層方向から見て重なるように平行に配され、
前記第１〜第４の片端短絡矩形状共振電極は略同一の形状を有し、前記第１および第３の片端短絡矩形状共振電極は前記第２の誘電体層を挟んでそれぞれの少なくとも一部が積層方向から見て重なるように平行に配されるとともに、前記第２および第４の片端短絡矩形状共振電極は前記第２の誘電体層を挟んでそれぞれの少なくとも一部が積層方向から見て重なるように平行に配され、
前記第１および第２の接地電極は積層方向から見て前記第１〜第４の片端開放矩形状共振電極ならびに前記第１〜第４の片端短絡矩形状共振電極を覆うように配され、
前記第１の片端開放矩形状共振電極の開放端と反対側の端部と、前記第１の片端短絡矩形状共振電極の短絡端と反対側の端部とを電気的に接続して第１の共振器を形成し、
前記第２の片端開放矩形状共振電極の開放端と反対側の端部と、前記第２の片端短絡矩形状共振電極の短絡端と反対側の端部とを電気的に接続して第２の共振器を形成し、
前記第３の片端開放矩形状共振電極の開放端と反対側の端部と、前記第３の片端短絡矩形状共振電極の短絡端と反対側の端部とを電気的に接続して第３の共振器を形成し、
前記第４の片端開放矩形状共振電極の開放端と反対側の端部と、前記第４の片端短絡矩形状共振電極の短絡端と反対側の端部とを電気的に接続して第４の共振器を形成し、
前記第１および第２の共振器ならびに前記第３および第４の共振器とが、前記第１〜第４の共振器の長さ方向と積層方向で構成される平面に関して面対称に配されるとともに、前記第１および第３の共振器に平衡型の入力端子ならびに前記第２および第４の共振器に平衡型の出力端子が電気的に接続されるか、または前記第１および第３の共振器に平衡型の出力端子ならびに前記第２および第４の共振器に平衡型の入力端子が電気的に接続されていることを特徴とするものである。
【００１６】
本発明の平衡型積層ストリップラインフィルタによれば、第１および第３の共振器が第２の誘電体層を挟んでそれぞれの少なくとも一部が積層方向から見て重なるように対向して配されるとともに、第２および第４の共振器が第２の誘電体層を挟んでそれぞれの少なくとも一部が積層方向から見て重なるように対向して配されていることから、第１および第３の共振器間と第２および第４の共振器間で形成される電磁界結合はブロードサイド結合となり、大きな電磁界結合を実現でき、この結果、広帯域なフィルタ特性を実現することができる。
【００１７】
また、第１および第２の共振器ならびに第３および第４の共振器とが、第１〜第４の共振器の長さ方向と積層方向で構成される平面に関して面対称に配されていることから、第１および第２の共振器間と第３および第４の共振器間に形成される電位零の電気壁によって外部雑音が相殺され、外部雑音に強い平衡型積層ストリップラインフィルタを実現することができるとともに、複数の誘電体層を積層する工程において発生する積層ずれが発生した場合でも、第１および第３の共振器間で形成される電磁界結合と第２および第４の共振器間で形成される電磁界結合の増減の割合が一定となることから、第１および第３の共振器間で形成される電磁界結合と第２および第４の共振器間で形成される電磁界結合の増減によるフィルタ特性の減衰極の変動を互いに相殺させることが可能となり、フィルタ特性の減衰極の変動を低減することができる。
【００１８】
また、本発明の平衡型積層ストリップラインフィルタは、上記構成において、前記各接地電極が、または前記各片端短絡矩形状共振電極の短絡端および前記各接地電極が、前記誘電体層の内部に形成された貫通導体および／または側面に形成された側面導体により積層方向に電気的に接続されていることを特徴とするものである。
【００１９】
これにより、積層された複数の誘電体層の内部に形成する平衡型積層ストリップラインフィルタの設計自由度が向上するとともに、小型で高性能な平衡型積層ストリップラインフィルタを提供することができる。
【００２０】
【発明の実施の形態】
以下、本発明の平衡型積層ストリップラインフィルタを図面を参照しつつ説明する。
【００２１】
図１は本発明の平衡型積層ストリップラインフィルタの実施の形態の一例を示す透視斜視図であり、図２は図１を積層方向から見た透視平面図、図３は図２におけるａ−ａ’線断面図である。図１〜図３において、３１は第１の誘電体層、３２は第１の誘電体層３１の上に積層された第２の誘電体層、３３は第２の誘電体層３２の上に積層された第３の誘電体層、４０は第１の誘電体層３１の下面に配された第１の接地電極、４１は第３の誘電体層３３の上面に配された第２の接地電極、４２および４３はそれぞれ第１および第２の誘電体層３１・３２の間に配した第１および第２の片端開放矩形状共振電極、４４および４５はそれぞれ第１および第２の誘電体層３１・３２の間に配した第１および第２の片端短絡矩形状共振電極、４６および４７はそれぞれ第２および第３の誘電体層３２・３３の間に配した第３および第４の片端開放矩形状共振電極、４８および４９はそれぞれ第２および第３の誘電体層３２・３３の間に配した第３および第４の片端短絡矩形状共振電極、５０は第１〜第４の片端開放矩形状共振電極４２・４３・４６・４７のそれぞれの開放端、５１は第１〜第４の片端短絡矩形状共振電極４４・４５・４８・４９のそれぞれの短絡端である。
【００２２】
そして、図１〜図３に示すように、第１〜第４の片端開放矩形状共振電極４２・４３・４６・４７は略同一の形状を有し、第１および第３の片端開放矩形状共振電極４２・４６は第２の誘電体層３２を挟んでそれぞれの少なくとも一部が積層方向から見て重なるように平行に配されるとともに、第２および第４の片端開放矩形状共振電極４３・４７は第２の誘電体層３２を挟んでそれぞれの少なくとも一部が積層方向から見て重なるように平行に配されている。また、第１〜第４の片端短絡矩形状共振電極４４・４５・４８・４９は略同一の形状を有し、第１および第３の片端短絡矩形状共振電極４４・４８は第２の誘電体層３２を挟んでそれぞれの少なくとも一部が積層方向から見て重なるように平行に配されるとともに、第２および第４の片端短絡矩形状共振電極４５・４９は第２の誘電体層３２を挟んでそれぞれの少なくとも一部が積層方向から見て重なるように平行に配されている。また、第１および第２の接地電極４０・４１は積層方向から見て第１〜第４の片端開放矩形状共振電極４２・４３・４６・４７ならびに第１〜第４の片端短絡矩形状共振電極４４・４５・４８・４９を覆うように配されている。
【００２３】
そして、第１の片端開放矩形状共振電極４２の開放端５０と反対側の端部と、第１の片端短絡矩形状共振電極４４の短絡端５１と反対側の端部とを電気的に接続して第１の共振器７１を形成し、
第２の片端開放矩形状共振電極４３の開放端５０と反対側の端部と、第２の片端短絡矩形状共振電極４５の短絡端５１と反対側の端部とを電気的に接続して第２の共振器７２を形成し、
第３の片端開放矩形状共振電極４６の開放端５０と反対側の端部と、第３の片端短絡矩形状共振電極４８の短絡端５１と反対側の端部とを電気的に接続して第３の共振器７３を形成し、
第４の片端開放矩形状共振電極４７の開放端５０と反対側の端部と、第４の片端短絡矩形状共振電極４９の短絡端５１と反対側の端部とを電気的に接続して第４の共振器７４を形成している。
【００２４】
そして、さらに、第１および第２の共振器７１・７２ならびに第３および第４の共振器７３・７４とが、第１〜第４の共振器７１〜７４の長さ方向と積層方向で構成される平面に関して面対称に配されるとともに、第１および第３の共振器７１・７３に平衡型の入力端子６１ａ・６１ｂが電気的に接続され、第２および第４の共振器７２・７４に平衡型の出力端子６２ａ・６２ｂが電気的に接続されている。
【００２５】
そして、平衡型の入力端子６１ａ・６１ｂおよび平衡型の出力端子６２ａ・６２ｂに外部平衡回路が電気的に接続され、平衡型の入力端子６１ａ・６１ｂに互いに位相が１８０°異なる高周波信号が入力され、平衡型の出力端子６２ａ・６２ｂから互いに位相が１８０°異なる高周波信号が出力される。
【００２６】
このような構成の本発明の平衡型積層ストリップラインフィルタは、第１および第２の接地電極４０・４１間、または第１および第２の接地電極４０・４１および第１〜第４の片端短絡矩形状共振電極４４・４５・４８・４９の短絡端５１を積層方向に電気的に接続する接地接続導体、および接続導体として誘電体層の内部に形成された貫通導体（図示せず）および／または側面に形成された側面導体（図示せず）を用いて構成することにより、３次元的な配線設計が可能となり、積層された複数の誘電体層の内部に形成する平衡型積層ストリップラインフィルタの設計自由度が向上するので、小型で高性能な平衡型積層ストリップラインを提供することができる。
【００２７】
本発明の平衡型積層ストリップラインフィルタを形成するに当たり、第１〜第３の誘電体層３１〜３３、第１および第２の接地電極４０・４１、第１〜第４の片端開放矩形状共振電極４２・４３・４６・４７、第１〜第４の片端短絡矩形状共振電極４４・４５・４８・４９は、周知の高周波用配線基板に使用される種々の材料・形態のものを使用することができる。
【００２８】
本発明の平衡型積層ストリップラインフィルタに用いる第１〜第３の誘電体層３１〜３３としては、例えばアルミナセラミックス・ムライトセラミックス等のセラミックス材料やガラスセラミックス等の無機系材料、あるいは四ふっ化エチレン樹脂（ポリテトラフルオロエチレン；ＰＴＦＥ）・四ふっ化エチレン−エチレン共重合樹脂（テトラフルオロエチレン−エチレン共重合樹脂；ＥＴＦＥ）・四ふっ化エチレン−パーフルオロアルコキシエチレン共重合樹脂（テトラフルオロエチレン−パーフルテロアルキルビニルエーテル共重合樹脂；ＰＦＡ）等のフッ素樹脂やガラスエポキシ樹脂・ポリイミド等の樹脂系材料等が用いられる。これらの材料による第１〜第３の誘電体層３１〜３３の形状や寸法（厚みや幅・長さ）は、使用される周波数や用途等に応じて設定される。
【００２９】
本発明の平衡型積層ストリップラインフィルタにおける第１および第２の接地電極４０・４１、第１〜第４の片端開放矩形状共振電極４２・４３・４６・４７、第１〜第４の片端短絡矩形状共振電極４４・４５・４８・４９、貫通導体は、高周波信号伝送用の金属材料の導体層、例えばＣｕ層・Ｍｏ−Ｍｎのメタライズ層上にＮｉメッキ層およびＡｕメッキ層を被着させたもの・Ｗのメタライズ層上にＮｉメッキ層およびＡｕメッキ層を被着させたもの・Ｃｒ−Ｃｕ合金層・Ｃｒ−Ｃｕ合金層上にＮｉメッキ層およびＡｕメッキ層を被着させたもの・Ｔａ_２Ｎ層上にＮｉ−Ｃｒ合金層およびＡｕメッキ層を被着させたもの・Ｔｉ層上にＰｔ層およびＡｕメッキ層を被着させたもの、またはＮｉ−Ｃｒ合金層上にＰｔ層およびＡｕメッキ層を被着させたもの等を用いて、厚膜印刷法あるいは各種の薄膜形成方法やメッキ法等により形成される。その厚みや幅も、伝送される高周波信号の周波数や用途等に応じて設定される。
【００３０】
本発明の平衡型積層ストリップラインフィルタに用いる第１〜第３の誘電体層３１〜３３の作製にあたっては、例えば誘電体層がガラスセラミックスから成る場合であれば、まず誘電体層となるガラスセラミックスのグリーンシートを準備し、これに所定の打ち抜き加工を施して貫通導体となる貫通孔を形成した後、スクリーン印刷法によりＣｕ等の導体ペーストを貫通孔に充填するとともに、所定の伝送線路パターンおよびその他の導体層のパターンを印刷塗布する。次に、８５０〜１０００℃で焼成を行ない、最後に外表面に露出している導体層上にＮｉメッキおよびＡｕメッキを施す。
【００３１】
図１〜図３に示す構成の本発明の平衡型積層ストリップラインフィルタならびに図６および図７に示す従来の平衡型積層ストリップラインフィルタは、同一のフィルタ特性を実現でき、図４はその代表的なフィルタ特性を示したものである。図４において横軸は周波数（単位：ＧＨｚ）を、縦軸は挿入損失（単位：ｄＢ）を、ｆｒは減衰極を表す。
【００３２】
図５は、図１〜図３に示す構成の本発明の平衡型積層ストリップラインフィルタならびに図６および図７に示す従来の平衡型積層ストリップラインフィルタの構造モデルを３次元電磁界解析シミュレータで作成し、幅方向の積層ずれ量として±１００μｍを考慮した場合のシミュレーション結果における減衰極ｆｒの変化量を示す各線図である。
【００３３】
例えば、図１〜図３に示す構成の本発明の平衡型積層ストリップラインフィルタにおけるシミュレーションの場合、第１〜第３の誘電体層３１〜３３の厚みをそれぞれ０．１０ｍｍ、第１〜第４の片端開放矩形状共振電極４２・４３・４６・４７の各共振電極の幅Ｗ１と長さＬ１をそれぞれＷ１＝１．１１ｍｍとＬ１＝２．２６ｍｍ、第１および第３の片端開放矩形状共振電極４２・４６ならびに第２および第４の片端開放矩形状共振電極４３・４７が積層方向から見て重なる部分の幅Ｗ２をＷ２＝０．５４ｍｍ、第１〜第４の片端短絡矩形状共振電極４４・４５・４８・４９の各共振電極の幅Ｗ３と長さＬ２をそれぞれＷ３＝１．１６ｍｍとＬ２＝２．２６ｍｍ、第１および第３の片端短絡矩形状共振電極４４・４８ならびに第２および第４の片端短絡矩形状共振電極４５・４９が積層方向から見て重なる部分の幅Ｗ４をＷ４＝０．３０ｍｍとしている。そして、第１および第２の共振器７１・７２がある面と第３および第４の共振器７３・７４がある面とが幅方向に積層ずれした量として±１００μｍを考慮した場合についてシミュレーションを実施した。また、図６および図７に示す従来の平衡型積層ストリップラインフィルタにおいても、同様の構造モデルを３次元電磁界解析シミュレータで作成し、幅方向の積層ずれ量として±１００μｍを考慮した場合についてシミュレーションを実施した。各シミュレーションの際に用いた各誘電体層の比誘電率は１０に設定した。
【００３４】
図５において、横軸は幅方向の積層ずれ量（単位：μｍ）を、縦軸は減衰極ｆｒの変化量（単位：ＭＨｚ）を表し、各特性曲線は、Ａが図１〜図３に示す本発明の平衡型積層ストリップラインフィルタにおける結果を、Ｂが図６および図７に示す従来の平衡型積層ストリップラインフィルタにおける結果を示している。
【００３５】
図５に示す結果から明らかなように、本発明の平衡型積層ストリップラインフィルタによれば、複数の誘電体層を積層する工程において発生する積層ずれによる、フィルタ特性の減衰極の変動を低減することができる。
【００３６】
例えば、積層ずれ量−１００μｍにおける減衰極ｆｒの変化量についてみると、Ａ…減衰極ｆｒの変化量：−８ＭＨｚ
Ｂ…減衰極ｆｒの変化量：−１９２ＭＨｚ
であり、従来の平衡型積層ストリップラインフィルタにおける結果（Ｂ）に比べて、本発明の平衡型積層ストリップラインフィルタにおける結果（Ａ）は、減衰極ｆｒの変化量を低減することができることが分かる。
【００３７】
また、図１〜図３に示す構成の本発明の平衡型積層ストリップラインフィルタによれば、第１および第３の共振器７１・７３が第２の誘電体層３２を挟んでそれぞれの少なくとも一部が積層方向から見て重なるように対向して配されるとともに、第２および第４の共振器７２・７４が第２の誘電体層３２を挟んでそれぞれの少なくとも一部が積層方向から見て重なるように対向して配されていることから、第１および第３の共振器７１・７３間と第２および第４の共振器７２・７４間で形成される電磁界結合はブロードサイド結合となり、大きな電磁界結合を実現できるので、広帯域なフィルタ特性を実現することができる。
【００３８】
また、第１および第２の共振器７１・７２ならびに第３および第４の共振器７３・７４とが、第１〜第４の共振器７１〜７４の長さ方向と積層方向で構成される平面に関して面対称に配されていることから、平衡型の入力端子６１ａ・６１ｂに互いに位相が１８０°異なる高周波信号が入力され、平衡型の出力端子６２ａ・６２ｂから互いに位相が１８０°異なる高周波信号が出力されたとき、上記の対称面は常に零電位となり、第１および第２の共振器７１・７２間と第３および第４の共振器７３・７４間に電位零の仮想的な電気壁が形成されるので外部雑音が第１〜第４の共振器７１〜７４に作用しても互いに相殺され、外部雑音に強い平衡型積層ストリップラインフィルタを実現することができる。
【００３９】
また、本発明の平衡型積層ストリップラインフィルタは、上記構成において、第１および第２の接地電極４０・４１を積層方向に電気的に接続する接地接続導体および第１〜第４の片端短絡矩形状共振電極４４・４５・４８・４９の短絡端５１を積層方向に電気的に接続する接続導体が誘電体層の内部に形成された貫通導体および／または側面に形成された側面導体であることを特徴とするものであり、これにより、積層された複数の誘電体層の内部に形成する平衡型積層ストリップラインフィルタの設計自由度が向上するとともに、小型で高性能な平衡型積層ストリップラインフィルタを提供することができる。
【００４０】
なお、本発明は以上の実施の形態の例に限定されるものではなく、本発明の要旨を逸脱しない範囲で種々の変更・改良を加えることは何ら差し支えない。
【００４１】
【発明の効果】
本発明の平衡型積層ストリップラインフィルタによれば、第１および第３の共振器が第２の誘電体層を挟んでそれぞれの少なくとも一部が積層方向から見て重なるように対向して配されるとともに、第２および第４の共振器が第２の誘電体層を挟んでそれぞれの少なくとも一部が積層方向から見て重なるように対向して配されていることから、第１および第３の共振器間と第２および第４の共振器間で形成される電磁界結合はブロードサイド結合となり、大きな電磁界結合を実現でき、この結果、広帯域なフィルタ特性を実現することができる。
【００４２】
また、第１および第２の共振器ならびに第３および第４の共振器とが、第１〜第４の共振器の長さ方向と積層方向で構成される平面に関して面対称に配されていることから、第１および第２の共振器間と第３および第４の共振器間に形成される電位零の電気壁によって外部雑音が相殺され、外部雑音に強い平衡型積層ストリップラインフィルタを実現することができるとともに、複数の誘電体層を積層する工程において発生する積層ずれが発生した場合でも、第１および第３の共振器間で形成される電磁界結合と第２および第４の共振器間で形成される電磁界結合の増減の割合が一定となることから、第１および第３の共振器間で形成される電磁界結合と第２および第４の共振器間で形成される電磁界結合の増減によるフィルタ特性の減衰極の変動を互いに相殺させることが可能となり、フィルタ特性の減衰極の変動を低減することができる。
【００４３】
また、本発明の平衡型積層ストリップラインフィルタは、上記構成において、各接地電極が、または各片端短絡矩形状共振電極の短絡端および各接地電極が、誘電体層の内部に形成された貫通導体および／または側面に形成された側面導体により積層方向に電気的に接続されていることを特徴とするものである。
【００４４】
これにより、積層された複数の誘電体層の内部に形成する平衡型積層ストリップラインフィルタの設計自由度が向上するとともに、小型で高性能な平衡型積層ストリップラインを提供することができる。
【００４５】
以上のように、本発明によれば、平衡型積層ストリップラインフィルタにおいて、複数の誘電体層を積層する工程において発生する積層ずれによるフィルタ特性の減衰極の変動を低減することができる広帯域な平衡型積層ストリップラインフィルタを提供することができた。
【図面の簡単な説明】
【図１】本発明の平衡型積層ストリップラインフィルタの実施の形態の一例を示す透視斜視図である。
【図２】本発明の平衡型積層ストリップラインフィルタの実施の形態の一例を示す透視平面図である。
【図３】本発明の平衡型積層ストリップラインフィルタの実施の形態の一例を示す図２におけるａ−ａ’線断面図である。
【図４】本発明の平衡型積層ストリップラインフィルタおよび従来の平衡型積層ストリップラインフィルタにおける挿入損失の例を示す線図である。
【図５】本発明の平衡型積層ストリップラインフィルタおよび従来の平衡型積層ストリップラインフィルタにおける幅方向の積層ずれ量に対する、減衰極の変化量の例を示す線図である。
【図６】従来の平衡型積層ストリップラインフィルタの例を示す透視斜視図である。
【図７】従来の平衡型積層ストリップラインフィルタの例を示す断面図である。
【図８】従来の平衡型積層ストリップラインフィルタの他の例を示す透視斜視図である。
【図９】従来の平衡型積層ストリップラインフィルタの他の例を示す断面図である。
【符号の説明】
３１・・・第１の誘電体層
３２・・・第２の誘電体層
３３・・・第３の誘電体層
４０・・・第１の接地電極
４１・・・第２の接地電極
４２・・・第１の片端開放矩形状共振電極
４３・・・第２の片端開放矩形状共振電極
４４・・・第１の片端短絡矩形状共振電極
４５・・・第２の片端短絡矩形状共振電極
４６・・・第３の片端開放矩形状共振電極
４７・・・第４の片端開放矩形状共振電極
４８・・・第３の片端短絡矩形状共振電極
４９・・・第４の片端短絡矩形状共振電極
５０・・・開放端
５１・・・短絡端
６１ａ、６１ｂ・・・平衡型の入力端子
６２ａ、６２ｂ・・・平衡型の出力端子
７１・・・第１の共振器
７２・・・第２の共振器
７３・・・第３の共振器
７４・・・第４の共振器[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a balanced laminated strip line filter used in, for example, wireless communication devices such as mobile phones and wireless LANs, and various other communication devices.
[0002]
[Prior art]
In recent years, filters used in mobile communication devices such as mobile phones have been resonating from distributed filters using filters using dielectric coaxial resonators in response to demands for thinner and smaller mobile communication devices. To the multilayer stripline filter used in the vessel. Further, from the viewpoint of high-frequency amplifier circuit design, unbalanced circuits have a problem that they are easily affected by external noise and the like, and balanced circuits have been adopted.
[0003]
Japanese Unexamined Patent Application Publication No. 11-317603 proposes a conventional balanced-type laminated stripline filter connected to this balanced-type circuit having a configuration shown in a perspective view in FIG. 8 and a sectional view in FIG. I have.
[0004]
8 and 9, reference numeral 10 denotes a dielectric, and 11 to 14 denote first to fourth resonators arranged in the dielectric 10. The first and second resonators 11 and 12 are electromagnetically coupled to each other to form a first pair of resonators 15, and the third and fourth resonators 13 and 14 are electromagnetically coupled to each other. A second pair of resonators 16 is formed, and a first pair of resonators 15 and a second pair of resonators 16 are disposed in the dielectric 10 so as to face each other and to be plane-symmetrical. The input terminals 18a and 18b and the output terminals 19a and 19b are connected to the four resonators 11 to 14, respectively, and the balanced input and output terminals 19a and 19b are formed by the input terminals 18a and 18b. It constitutes the output terminal of the mold.
[0005]
Further, a configuration has been proposed in which a ground conductor 17 is disposed at an electrical wall position between a first pair of resonators 15 and a second pair of resonators 16.
[0006]
Another configuration example of the conventional balanced type multilayer stripline filter shown in FIGS. 8 and 9 is shown in a perspective perspective view in FIG. 6 and a sectional view in FIG.
[0007]
6 and 7, 20a to 20f are dielectric layers, 20 is a dielectric, and the dielectric 20 is formed by sequentially laminating the dielectric layers 20a to 20f. 21 to 24 are first to fourth resonators arranged in the dielectric 20.
[0008]
The first and second resonators 21 and 22 are electromagnetically coupled to each other by being disposed so as to at least partially overlap each other with the dielectric layer 20e interposed therebetween, thereby forming a first pair of resonators. 25, and the third and fourth resonators 23 and 24 are disposed so as to face each other at least partially so as to overlap with each other with the dielectric layer 20b interposed therebetween. , And a first pair of resonators 25 and a second pair of resonators 26 are disposed in the dielectric 20 so as to face each other and in plane symmetry. Input terminals 28a and 28b and output terminals 29a and 29b are connected to the resonators 21 to 24, respectively, so that balanced input terminals formed by the input terminals 28a and 28b and balanced input terminals formed by the output terminals 29a and 29b are formed. Configure output terminals To have.
[0009]
Further, a configuration has been proposed in which a ground conductor 27 is disposed at an electrical wall position between a first pair of resonators 25 and a second pair of resonators 26.
[0010]
Then, in the conventional balanced-type laminated strip line filter shown in FIGS. 6 to 9, the potential of zero potential formed between the first pair of resonators 15 (25) and the second pair of resonators 16 (26) is reduced. External noise is canceled by the electric wall, and a balanced multilayer stripline filter that is strong against external noise has been realized.
[0011]
[Patent Document 1]
JP-A-11-317603
[0012]
[Problems to be solved by the invention]
However, in such a conventional balanced multilayer strip line filter, in the case of the configuration shown in FIGS. 8 and 9, the first and second resonators 11 and 12 and the third and fourth resonators 13 and 14 are provided. Are arranged on the same plane, and the electromagnetic field coupling formed between the first and second resonators 11 and 12 and between the third and fourth resonators 13 and 14 is edge-coupled. There has been a problem that electromagnetic field coupling cannot be realized, and thus a wideband filter characteristic cannot be realized.
[0013]
As a method of solving this problem, as shown in a perspective view of FIG. 6 and a sectional view of FIG. 7, the first and second resonators 21 and 22 are respectively sandwiched between dielectric layers 20e. By arranging the third and fourth resonators 23 and 24 to face each other at least partially so as to overlap with each other with the dielectric layer 20b interposed therebetween, The electromagnetic field coupling formed between the first and second resonators 21 and 22 and between the third and fourth resonators 23 and 24 is broadside coupling, and large electromagnetic field coupling can be realized. However, in this case, the gap between the first and second resonators 21 and 22 and the third and fourth resonators 23 are determined by the displacement of the stacked dielectric layers 20a to 20f.・ 2 Balance of the electromagnetic field coupling formed between collapses, the attenuation pole of the order filter characteristic is disadvantageously fluctuates.
[0014]
The present invention has been devised in view of the above problems, and an object of the present invention is to provide a balanced laminated strip line filter having a filter characteristic attenuation pole due to a lamination shift generated in a step of laminating a plurality of dielectric layers. An object of the present invention is to provide a broadband balanced multilayer stripline filter capable of reducing fluctuations.
[0015]
[Means for Solving the Problems]
The balanced laminated strip line filter according to the present invention includes a first dielectric layer, a second dielectric layer laminated on the first dielectric layer, and a second dielectric layer on the second dielectric layer. A laminated third dielectric layer, a first ground electrode disposed on the lower surface of the first dielectric layer, and first and second dielectric layers disposed between the first and second dielectric layers. A second open-ended rectangular resonant electrode, first and second open-ended rectangular resonant electrodes, and third and fourth open-ended rectangular shapes disposed between the second and third dielectric layers; A resonant electrode, third and fourth one-end short-circuited rectangular resonant electrodes, and a second ground electrode disposed on the upper surface of the third dielectric layer;
The first to fourth one-end open rectangular resonance electrodes have substantially the same shape, and the first and third one-end open rectangular resonance electrodes are at least one of each having the second dielectric layer interposed therebetween. Portions are arranged in parallel so as to overlap each other when viewed from the laminating direction, and the second and fourth one-end open rectangular resonance electrodes have at least a part of each of the second dielectric layers sandwiching the second dielectric layer from the laminating direction. Arranged in parallel so that they look
The first to fourth single-ended short-circuited rectangular resonant electrodes have substantially the same shape, and the first and third single-ended short-circuited rectangular resonant electrodes are at least one of each having the second dielectric layer interposed therebetween. Portions are arranged in parallel so as to overlap when viewed from the laminating direction, and at least a part of each of the second and fourth one-end short-circuited rectangular resonant electrodes is arranged from the laminating direction with the second dielectric layer interposed therebetween. Arranged in parallel so that they look
The first and second ground electrodes are disposed so as to cover the first to fourth single-ended rectangular resonant electrodes and the first to fourth single-ended short-circuited rectangular resonant electrodes as viewed from the lamination direction,
An end opposite to the open end of the first one-end open rectangular resonance electrode and an end opposite to the short-circuit end of the first one-end short-circuit rectangular resonance electrode are electrically connected to each other to form a first end. Forming a resonator of
An end of the second one-end open rectangular resonance electrode opposite to the open end and an end of the second one-end short-circuit rectangular resonance electrode opposite to the short-circuit end are electrically connected to form a second end. Forming a resonator of
An end of the third one-end open rectangular resonance electrode opposite to the open end and an end of the third one-end short-circuit rectangular resonance electrode opposite to the short-circuit end are electrically connected to form a third end. Forming a resonator of
By electrically connecting an end of the fourth one-end open rectangular resonance electrode opposite to the open end and an end of the fourth one-end short-circuit rectangular resonance electrode opposite to the short-circuit end, a fourth end is formed. Forming a resonator of
The first and second resonators and the third and fourth resonators are arranged plane-symmetrically with respect to a plane formed in the length direction and the stacking direction of the first to fourth resonators. And a balanced input terminal is electrically connected to the first and third resonators and a balanced output terminal is electrically connected to the second and fourth resonators, or the first and third resonators are connected to each other. A balanced output terminal is electrically connected to the resonator, and a balanced input terminal is electrically connected to the second and fourth resonators.
[0016]
According to the balanced multilayer strip line filter of the present invention, the first and third resonators are arranged to face each other with the second dielectric layer interposed therebetween so that at least a part of each of the resonators overlaps when viewed from the stacking direction. In addition, since the second and fourth resonators are disposed so as to at least partially overlap each other with the second dielectric layer interposed therebetween when viewed from the lamination direction, the first and third resonators are arranged. The electromagnetic field coupling formed between the resonators and between the second and fourth resonators is broadside coupling, so that a large electromagnetic field coupling can be realized, and as a result, a wide band filter characteristic can be realized.
[0017]
Further, the first and second resonators and the third and fourth resonators are arranged plane-symmetrically with respect to a plane formed in the length direction and the stacking direction of the first to fourth resonators. Therefore, external noise is canceled by the zero potential electric wall formed between the first and second resonators and between the third and fourth resonators, and a balanced laminated strip line filter resistant to external noise is realized. And the electromagnetic coupling formed between the first and third resonators and the second and fourth resonances can be performed even if a lamination shift occurs in the step of laminating the plurality of dielectric layers. Since the rate of increase and decrease of the electromagnetic field coupling formed between the devices is constant, the electromagnetic field coupling formed between the first and third resonators and the electromagnetic field coupling formed between the second and fourth resonators are formed. Attenuation pole of filter characteristics due to increase and decrease of electromagnetic field coupling It becomes possible to offset the variation with each other, it is possible to reduce the variation of the attenuation pole of the filter characteristics.
[0018]
Further, in the above-mentioned configuration, the grounding electrode, or the short-circuited end of each of the short-circuited rectangular resonant electrodes and the grounding electrode may be formed inside the dielectric layer. Characterized in that they are electrically connected in the stacking direction by the through conductors and / or side conductors formed on the side surfaces.
[0019]
Thus, the degree of freedom in designing a balanced multilayer stripline filter formed inside a plurality of stacked dielectric layers is improved, and a compact, high-performance balanced multilayer stripline filter can be provided.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a balanced laminated strip line filter of the present invention will be described with reference to the drawings.
[0021]
FIG. 1 is a perspective perspective view showing an example of an embodiment of a balanced laminated strip line filter of the present invention, FIG. 2 is a perspective plan view of FIG. 1 viewed from the lamination direction, and FIG. 3 is aa in FIG. FIG. 1 to 3, reference numeral 31 denotes a first dielectric layer, 32 denotes a second dielectric layer laminated on the first dielectric layer 31, and 33 denotes a second dielectric layer on the second dielectric layer 32. The laminated third dielectric layer, 40 is a first ground electrode disposed on the lower surface of the first dielectric layer 31, and 41 is the second ground electrode disposed on the upper surface of the third dielectric layer 33. Electrodes, 42 and 43 are first and second open-ended rectangular resonant electrodes disposed between first and second dielectric layers 31 and 32, respectively, and 44 and 45 are first and second dielectric layers, respectively. The first and second single-ended short-circuited rectangular resonance electrodes 46 and 47 disposed between the layers 31 and 32 are the third and fourth rectangular electrodes disposed between the second and third dielectric layers 32 and 33, respectively. One end open rectangular resonance electrodes 48 and 49 are disposed between the second and third dielectric layers 32 and 33, respectively. 3rd and 4th one-end short-circuited rectangular resonance electrodes, 50 is the open end of each of the first to fourth one-end open rectangular resonance electrodes 42, 43, 46, 47, and 51 is the 1st to fourth one-end short-circuited rectangular electrodes. These are short-circuit ends of the shape resonance electrodes 44, 45, 48, and 49, respectively.
[0022]
As shown in FIGS. 1 to 3, the first to fourth one-end open rectangular resonant electrodes 42, 43, 46 and 47 have substantially the same shape, and the first and third one-end open rectangular shapes are formed. The resonance electrodes 42 and 46 are arranged in parallel so that at least a part of each of them overlaps with the second dielectric layer 32 interposed therebetween when viewed from the laminating direction. 47 are arranged in parallel so that at least a part of each of them overlaps with the second dielectric layer 32 therebetween when viewed from the laminating direction. Further, the first to fourth single-ended short-circuited rectangular resonant electrodes 44, 45, 48, and 49 have substantially the same shape, and the first and third single-ended short-circuited rectangular resonant electrodes 44, 48 are provided with a second dielectric material. At least a part of each of them is arranged in parallel so as to overlap with each other with the body layer 32 interposed therebetween when viewed from the laminating direction. Are arranged in parallel so that at least a part of each overlaps when viewed from the stacking direction. The first and second ground electrodes 40 and 41 are first to fourth one-end open rectangular resonance electrodes 42, 43, 46 and 47, and first to fourth one-end short-circuit rectangular resonance when viewed from the lamination direction. It is arranged so as to cover the electrodes 44, 45, 48, 49.
[0023]
Then, an end of the first one-end open rectangular resonance electrode 42 opposite to the open end 50 and an end of the first one-end short-circuit rectangular resonance electrode 44 opposite to the short-circuit end 51 are electrically connected. To form a first resonator 71,
An end of the second one-end open rectangular resonance electrode 43 opposite to the open end 50 is electrically connected to an end of the second one-end short-circuit rectangular resonance electrode 45 opposite to the short-circuit end 51. Forming a second resonator 72,
An end of the third one-end open rectangular resonance electrode 46 opposite to the open end 50 is electrically connected to an end of the third one-end short-circuit rectangular resonance electrode 48 opposite to the short-circuit end 51. Forming a third resonator 73;
An end of the fourth one-end open rectangular resonance electrode 47 opposite to the open end 50 and an end of the fourth one-end short-circuit rectangular resonance electrode 49 opposite to the short-circuit end 51 are electrically connected to each other. A fourth resonator 74 is formed.
[0024]
Further, the first and second resonators 71 and 72 and the third and fourth resonators 73 and 74 are configured in the length direction and the stacking direction of the first to fourth resonators 71 to 74. And balanced input terminals 61a and 61b are electrically connected to the first and third resonators 71 and 73, respectively, and the second and fourth resonators 72 and 74 are arranged. Are electrically connected to balanced output terminals 62a and 62b.
[0025]
An external balanced circuit is electrically connected to the balanced input terminals 61a and 61b and the balanced output terminals 62a and 62b, and high-frequency signals having phases different from each other by 180 ° are input to the balanced input terminals 61a and 61b. , High-frequency signals whose phases are different from each other by 180 ° are output from the balanced output terminals 62a and 62b.
[0026]
The balanced type laminated strip line filter of the present invention having such a configuration is capable of short-circuiting between the first and second ground electrodes 40 and 41 or between the first and second ground electrodes 40 and 41 and the first to fourth one-ends. A ground connection conductor for electrically connecting the short-circuited ends 51 of the rectangular resonance electrodes 44, 45, 48, 49 in the stacking direction, and a through conductor (not shown) formed inside the dielectric layer as a connection conductor and / or Alternatively, by using side conductors (not shown) formed on the side surfaces, a three-dimensional wiring design becomes possible, and a balanced laminated strip line filter formed inside a plurality of laminated dielectric layers. Since the degree of freedom of design of the device is improved, it is possible to provide a compact and high-performance balanced laminated strip line.
[0027]
In forming the balanced laminated strip line filter of the present invention, first to third dielectric layers 31 to 33, first and second ground electrodes 40 and 41, first to fourth open-ended rectangular resonators at one end. The electrodes 42, 43, 46, 47 and the first to fourth single-ended short-circuited rectangular resonance electrodes 44, 45, 48, 49 use various materials and forms used for known high-frequency wiring boards. be able to.
[0028]
The first to third dielectric layers 31 to 33 used in the balanced laminated strip line filter of the present invention include, for example, ceramic materials such as alumina ceramics and mullite ceramics, inorganic materials such as glass ceramics, and ethylene tetrafluoride. Resin (polytetrafluoroethylene; PTFE), ethylene tetrafluoride-ethylene copolymer resin (tetrafluoroethylene-ethylene copolymer resin; ETFE), ethylene tetrafluoride-perfluoroalkoxyethylene copolymer resin (tetrafluoroethylene-per Fluororesins such as furteroalkyl vinyl ether copolymer resin (PFA) and resin materials such as glass epoxy resin and polyimide are used. The shapes and dimensions (thickness, width and length) of the first to third dielectric layers 31 to 33 made of these materials are set according to the frequency used, the application, and the like.
[0029]
The first and second ground electrodes 40 and 41, the first to fourth one-end open rectangular resonance electrodes 42, 43, 46 and 47, and the first to fourth one-end short-circuits in the balanced laminated strip line filter of the present invention. The rectangular resonance electrodes 44, 45, 48, 49 and the through conductor are formed by depositing a Ni plating layer and an Au plating layer on a conductor layer of a metal material for transmitting a high frequency signal, for example, a metallized layer of a Cu layer / Mo-Mn.・ Ni plating layer and Au plating layer deposited on W metallization layer ・ Cr-Cu alloy layer ・ Ni plating layer and Au plating layer deposited on Cr-Cu alloy layer Ta ₂ Ni-Cr alloy layer and Au plating layer deposited on N layer-Pt layer and Au plating layer deposited on Ti layer, or Pt layer and Au plating on Ni-Cr alloy layer It is formed by a thick film printing method, various thin film forming methods, a plating method, or the like, using a material having a layer adhered thereto. The thickness and width are also set according to the frequency of the transmitted high-frequency signal, the application, and the like.
[0030]
In manufacturing the first to third dielectric layers 31 to 33 used in the balanced laminated strip line filter of the present invention, for example, when the dielectric layer is made of glass ceramic, first, a glass ceramic to be a dielectric layer is used. After preparing a green sheet of, and performing a predetermined punching process to form a through hole to be a through conductor, filling the through hole with a conductive paste such as Cu by a screen printing method, a predetermined transmission line pattern and Print and apply other conductor layer patterns. Next, baking is performed at 850 to 1000 ° C., and finally Ni plating and Au plating are performed on the conductor layer exposed on the outer surface.
[0031]
The balanced multilayer strip line filter of the present invention having the configuration shown in FIGS. 1 to 3 and the conventional balanced multilayer strip line filter shown in FIGS. 6 and 7 can realize the same filter characteristics, and FIG. FIG. In FIG. 4, the horizontal axis represents frequency (unit: GHz), the vertical axis represents insertion loss (unit: dB), and fr represents an attenuation pole.
[0032]
FIG. 5 shows a structure model of the balanced multilayer strip line filter of the present invention having the configuration shown in FIGS. 1 to 3 and a conventional balanced multilayer strip line filter shown in FIGS. 6 and 7 created by a three-dimensional electromagnetic field analysis simulator. FIG. 9 is a diagram illustrating the amount of change in the attenuation pole fr in the simulation result when ± 100 μm is considered as the amount of stacking deviation in the width direction.
[0033]
For example, in the case of the simulation in the balanced laminated strip line filter of the present invention having the configuration shown in FIGS. 1 to 3, the thicknesses of the first to third dielectric layers 31 to 33 are 0.10 mm, , The width W1 and the length L1 of each of the resonance electrodes 42, 43, 46, 47 of W1 = 1.11 mm and L1 = 2.26 mm, respectively. The width W2 of the portion where the electrodes 42 and 46 and the second and fourth open-ended rectangular resonant electrodes 43 and 47 overlap when viewed in the laminating direction is W2 = 0.54 mm, and the first to fourth single-ended short-circuited rectangular resonant electrodes are provided. The width W3 and the length L2 of each of the resonance electrodes 44, 45, 48, 49 are W3 = 1.16 mm and L2 = 2.26 mm, respectively, and the first and third one-side short-circuited rectangular resonance electrodes 44, 48 and the second are respectively. And the first At one end short rectangular resonant electrodes 45, 49 are a width W4 of the portion that overlaps when viewed from the lamination direction and W4 = 0.30 mm. Then, a simulation was performed for a case where ± 100 μm was considered as the amount of misalignment in the width direction between the surface where the first and second resonators 71 and 72 are located and the surface where the third and fourth resonators 73 and 74 are located. Carried out. Also, in the conventional balanced multilayer stripline filter shown in FIGS. 6 and 7, a similar structural model is created by a three-dimensional electromagnetic field analysis simulator, and a simulation is performed in a case where ± 100 μm is considered as a lamination displacement in the width direction. Was carried out. The relative dielectric constant of each dielectric layer used in each simulation was set to 10.
[0034]
In FIG. 5, the horizontal axis represents the amount of lamination displacement (unit: μm) in the width direction, and the vertical axis represents the amount of change (unit: MHz) of the attenuation pole fr. B shows the result of the balanced multilayer strip line filter of the present invention, and B shows the result of the conventional balanced multilayer strip line filter shown in FIGS. 6 and 7.
[0035]
As is clear from the results shown in FIG. 5, according to the balanced multilayer strip line filter of the present invention, the variation in the attenuation pole of the filter characteristics due to the lamination displacement occurring in the step of laminating a plurality of dielectric layers is reduced. be able to.
[0036]
For example, looking at the variation of the attenuation pole fr when the stacking deviation is −100 μm, A: variation of the attenuation pole fr: −8 MHz
B: Amount of change in attenuation pole fr: -192 MHz
It can be seen that the result (A) of the balanced multilayer strip line filter of the present invention can reduce the amount of change in the attenuation pole fr as compared with the result (B) of the conventional balanced multilayer strip line filter. .
[0037]
Further, according to the balanced multilayer stripline filter of the present invention having the configuration shown in FIGS. 1 to 3, the first and third resonators 71 and 73 each have at least one of the two resonators sandwiching the second dielectric layer 32. The second and fourth resonators 72 and 74 are arranged such that the portions overlap each other when viewed from the stacking direction, and at least a part of each of the second and fourth resonators 72 and 74 is viewed from the stacking direction with the second dielectric layer 32 interposed therebetween. The electromagnetic field coupling formed between the first and third resonators 71 and 73 and between the second and fourth resonators 72 and 74 is broadside coupling. , And a large electromagnetic field coupling can be realized, so that a wide band filter characteristic can be realized.
[0038]
Further, the first and second resonators 71 and 72 and the third and fourth resonators 73 and 74 are configured in the length direction and the stacking direction of the first to fourth resonators 71 to 74. Since they are arranged plane-symmetrically with respect to the plane, high-frequency signals having phases different from each other by 180 ° are input to the balanced input terminals 61a and 61b, and high-frequency signals having phases different from each other by 180 ° from the balanced output terminals 62a and 62b. Is output, the above-mentioned plane of symmetry always becomes zero potential, and a virtual electric wall having a potential of zero between the first and second resonators 71 and 72 and between the third and fourth resonators 73 and 74. Is formed, even if external noise acts on the first to fourth resonators 71 to 74, they cancel each other out, and a balanced laminated strip line filter resistant to external noise can be realized.
[0039]
Further, in the above-described balanced multilayer strip line filter according to the present invention, the ground connection conductor for electrically connecting the first and second ground electrodes 40 and 41 in the stacking direction and the first to fourth single-ended short-circuited rectangular strip filters. The connection conductor that electrically connects the short-circuited ends 51 of the shape resonance electrodes 44, 45, 48, and 49 in the stacking direction is a through conductor formed inside the dielectric layer and / or a side conductor formed on the side surface. Thereby, the degree of freedom in designing a balanced multilayer strip line filter formed inside a plurality of stacked dielectric layers is improved, and a small and high-performance balanced multilayer strip line filter is provided. Can be provided.
[0040]
It should be noted that the present invention is not limited to the above-described embodiments, and various changes and improvements may be made without departing from the spirit of the present invention.
[0041]
【The invention's effect】
According to the balanced multilayer strip line filter of the present invention, the first and third resonators are arranged to face each other with the second dielectric layer interposed therebetween so that at least a part of each of the resonators overlaps when viewed from the stacking direction. In addition, since the second and fourth resonators are disposed so as to at least partially overlap each other with the second dielectric layer interposed therebetween when viewed from the lamination direction, the first and third resonators are arranged. The electromagnetic field coupling formed between the resonators and between the second and fourth resonators is broadside coupling, so that a large electromagnetic field coupling can be realized, and as a result, a wide band filter characteristic can be realized.
[0042]
Further, the first and second resonators and the third and fourth resonators are arranged plane-symmetrically with respect to a plane formed in the length direction and the stacking direction of the first to fourth resonators. Therefore, external noise is canceled by the zero potential electric wall formed between the first and second resonators and between the third and fourth resonators, and a balanced laminated strip line filter resistant to external noise is realized. And the electromagnetic coupling formed between the first and third resonators and the second and fourth resonances can be performed even if a lamination shift occurs in the step of laminating the plurality of dielectric layers. Since the rate of increase and decrease of the electromagnetic field coupling formed between the devices is constant, the electromagnetic field coupling formed between the first and third resonators and the electromagnetic field coupling formed between the second and fourth resonators are formed. Attenuation pole of filter characteristics due to increase / decrease of electromagnetic field coupling It becomes possible to offset the variation with each other, it is possible to reduce the variation of the attenuation pole of the filter characteristics.
[0043]
Further, in the balanced laminated strip line filter of the present invention, in the above-described configuration, each of the ground electrodes, or the short-circuited end of each one-end short-circuited rectangular resonance electrode and each of the ground electrodes are formed in a through conductor formed inside the dielectric layer. And / or electrically connected in the laminating direction by side conductors formed on the side surfaces.
[0044]
Thus, the degree of freedom in designing a balanced multilayer strip line filter formed inside a plurality of stacked dielectric layers is improved, and a compact and high-performance balanced multilayer strip line can be provided.
[0045]
As described above, according to the present invention, in a balanced multilayer stripline filter, a wideband balanced filter capable of reducing the variation of the attenuation pole of the filter characteristic due to the lamination shift generated in the step of laminating a plurality of dielectric layers. It was possible to provide a type laminated strip line filter.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of an embodiment of a balanced laminated strip line filter of the present invention.
FIG. 2 is a perspective plan view showing an example of an embodiment of a balanced laminated strip line filter of the present invention.
FIG. 3 is a cross-sectional view taken along the line aa ′ in FIG. 2 showing an example of an embodiment of the balanced laminated strip line filter of the present invention.
FIG. 4 is a diagram showing an example of insertion loss in the balanced laminated strip line filter of the present invention and a conventional balanced laminated strip line filter.
FIG. 5 is a diagram illustrating an example of a variation amount of an attenuation pole with respect to a lamination displacement amount in a width direction in a balanced multilayer strip line filter of the present invention and a conventional balanced multilayer strip line filter.
FIG. 6 is a perspective view showing an example of a conventional balanced-type laminated strip line filter.
FIG. 7 is a cross-sectional view illustrating an example of a conventional balanced multilayer strip line filter.
FIG. 8 is a perspective view showing another example of a conventional balanced-type laminated strip line filter.
FIG. 9 is a cross-sectional view showing another example of a conventional balanced multilayer strip line filter.
[Explanation of symbols]
31 first dielectric layer
32: second dielectric layer
33... Third dielectric layer
40... First ground electrode
41 ... second ground electrode
42... 1st open-ended rectangular resonant electrode
43... Second second open-ended rectangular resonant electrode
44... First one-end short-circuited rectangular resonance electrode
45... Second second-end short-circuited rectangular resonant electrode
46... Third third open-ended rectangular resonant electrode
47 Fourth open-ended rectangular resonant electrode
48 third third-end short-circuited rectangular resonant electrode
49... Fourth one-end short-circuited rectangular resonance electrode
50 ... open end
51 ・・・ Short-circuit end
61a, 61b ... balanced input terminals
62a, 62b ... balanced output terminals
71... First resonator
72... Second resonator
73... Third resonator
74... Fourth resonator

Claims

A first dielectric layer, a second dielectric layer laminated on the first dielectric layer, a third dielectric layer laminated on the second dielectric layer, A first ground electrode disposed on the lower surface of the first dielectric layer; a first and second one-end open rectangular resonance electrode disposed between the first and second dielectric layers; 1st and 2nd one-end short-circuited rectangular resonance electrodes, 3rd and 4th one-end open rectangular resonance electrodes arranged between the second and third dielectric layers, and 3rd and 4th one-end short-circuited A rectangular resonance electrode, and a second ground electrode disposed on the upper surface of the third dielectric layer,
The first to fourth one-end open rectangular resonance electrodes have substantially the same shape, and the first and third one-end open rectangular resonance electrodes are at least one of each having the second dielectric layer interposed therebetween. Portions are arranged in parallel so as to overlap each other when viewed from the laminating direction, and the second and fourth one-end open rectangular resonance electrodes have at least a part of each of the second dielectric layers sandwiching the second dielectric layer from the laminating direction. Arranged in parallel so that they look
The first to fourth single-ended short-circuited rectangular resonant electrodes have substantially the same shape, and the first and third single-ended short-circuited rectangular resonant electrodes are at least one of each having the second dielectric layer interposed therebetween. Portions are arranged in parallel so as to overlap when viewed from the laminating direction, and at least a part of each of the second and fourth one-end short-circuited rectangular resonant electrodes is arranged from the laminating direction with the second dielectric layer interposed therebetween. Arranged in parallel so that they look
The first and second ground electrodes are disposed so as to cover the first to fourth single-ended rectangular resonant electrodes and the first to fourth single-ended short-circuited rectangular resonant electrodes as viewed from the lamination direction,
An end opposite to the open end of the first one-end open rectangular resonance electrode and an end opposite to the short-circuit end of the first one-end short-circuit rectangular resonance electrode are electrically connected to each other to form a first end. Forming a resonator of
An end of the second one-end open rectangular resonance electrode opposite to the open end and an end of the second one-end short-circuit rectangular resonance electrode opposite to the short-circuit end are electrically connected to form a second end. Forming a resonator of
An end of the third one-end open rectangular resonance electrode opposite to the open end and an end of the third one-end short-circuit rectangular resonance electrode opposite to the short-circuit end are electrically connected to form a third end. Forming a resonator of
By electrically connecting an end of the fourth one-end open rectangular resonance electrode opposite to the open end and an end of the fourth one-end short-circuit rectangular resonance electrode opposite to the short-circuit end, a fourth end is formed. Forming a resonator of
The first and second resonators and the third and fourth resonators are arranged plane-symmetrically with respect to a plane formed in the length direction and the stacking direction of the first to fourth resonators. And a balanced input terminal is electrically connected to the first and third resonators and a balanced output terminal is electrically connected to the second and fourth resonators, or the first and third resonators are connected to each other. A balanced laminated strip line filter, wherein a balanced output terminal is electrically connected to the resonator and a balanced input terminal is electrically connected to the second and fourth resonators.

The ground electrodes, or the short-circuited ends of the single-ended short-circuited rectangular resonance electrodes and the ground electrodes are laminated by a through conductor formed inside the dielectric layer and / or a side conductor formed on a side surface. 2. The balanced laminated strip line filter according to claim 1, wherein the balanced strip line filter is electrically connected in the directions.