JP2004023333A

JP2004023333A - Non-reciprocal circuit element

Info

Publication number: JP2004023333A
Application number: JP2002173812A
Authority: JP
Inventors: Takefumi Terawaki; 寺脇　武文; Hidenobu Hanaki; 花木　秀信; Akinori Misawa; 三澤　彰規
Original assignee: Hitachi Metals Ltd
Current assignee: Proterial Ltd
Priority date: 2002-06-14
Filing date: 2002-06-14
Publication date: 2004-01-22
Anticipated expiration: 2022-06-14
Also published as: JP4085364B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-reciprocal circuit element that causes no deterioration in its electric characteristics even when downsized and enhances the mountability of a capacitor and an inductor being components of its LC circuit and the reliability of electric connection of them. <P>SOLUTION: The non-reciprocal circuit element is characterized in including: an assembly formed by arranging a plurality of center conductors to a ferrimagnetic body; a plurality of first capacitors placed between one end of a center conductor and ground; the surface mount inductor and the second capacitor being components of the LC circuit placed between the center conductor and an input terminal and / or an output terminal; a permanent magnet providing a DC magnetic field to the ferrimagnetic body; and a resin case to which the input terminal and the output terminal are formed. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、高周波信号に対して非可逆伝送特性を有する非可逆回路素子と、これに用いる樹脂ケースに関し、具体的には携帯電話などの移動体通信システムの中で使用され、一般にアイソレータやサーキュレータと呼ばれる非可逆回路素子及び樹脂ケースに関するものである。
【０００２】
【従来の技術】
従来、マイクロ波帯、ＵＨＦ帯で使用される携帯電話、自動車電話等の送受信回路部品の一つとしてアイソレータ，サーキュレータ等の非可逆回路素子がある。一般にアイソレータやサーキュレータは、アンプの破損を防止する目的で使用され、信号の伝送方向の挿入損失は小さく、かつ逆方向への逆方向損失は大きくなるような機能を持たせたものである。以下、本明細書では特開平１１−３０８０１３号に開示された非可逆回路素子のうちアイソレータを例にとって説明する。
【０００３】
図９に従来のアイソレータの一例を分解斜視図で示す。このアイソレータは、磁気ヨークとして機能する金属ケース（上ケース１、下ケース１２）、永久磁石２、組立体２０、平板コンデンサ（第１のコンデンサ）８、９、１０、ダミー抵抗１１、樹脂ケース７から構成されている。
前記組立体２０は、円板状のシールド板から放射状に３つの中心導体４、５、６が突出した構造の導体薄板を用意し、その導体薄板の円板状部にガーネットフェライト（フェリ磁性体）３を配置して、前記３つの中心導体４、５、６を折り曲げて重ねて一体に構成される。このとき、各中心導体４、５、６は絶縁されて重ねられる。
【０００４】
前記樹脂ケース７は、中央に、組立体２０用の円形状の凹部１３ａを有し、その周囲に平板コンデンサ用の凹部１３ｂ、１３ｃ、１３ｄを有する。この平板コンデンサ用の凹部１３ｂ、１３ｃ、１３ｄの底部及び組立体２０用の凹部１３ａには、接続電極１４ａが形成されている。そして、この接続電極１４ａは、一体の０．１ｍｍ程度の前記導体薄板で構成されており、樹脂ケースの側面部まで延出され、外部端子１５ａ〜１５ｆを構成している。この外部端子１５ｄ〜１５ｆは、外部端子１５ａ〜１５ｃの対向面に対称に形成されている。また、樹脂ケースには前記中心導体が接続される端子電極部１６ａ、１６ｄが形成されている。この端子電極部１６ａ、１６ｄは側面の外部端子１５ａ、１５ｄに導通するように形成されている。これら外部端子及び接続する端子電極部や接続電極は、同一の導体薄板から形成される。
【０００５】
この樹脂ケース７の凹部１３ｂ、１３ｃ、１３ｄにはそれぞれ平板コンデンサ８、９、１０が収容配置される。この平板コンデンサは、平板状の誘電体基板の上下面に電極を形成して構成されており、その下面の電極と、前記凹部の底部に形成された接続電極１４ａとが半田接続される。凹部１３ｄには平板コンデンサ１０とともにダミー抵抗１１が配置され、このダミー抵抗１１の一方の電極を接続電極１４ａに半田接続し、他方は中心導体６と接続する。
【０００６】
次いで、樹脂ケース７の凹部１３ａに、上記した組立体２０を配置する。このとき、中心導体部分の円板状のシールド板は、接続電極１４ａと半田接続される。これにより、中心導体の一端はアース接続される。中心導体４の一端は、平板コンデンサ８の上面の電極
と接続され、中心導体５の一端は、平板コンデンサ９の上面の電極と端子電極部１６ｄに接続される。そして端子電極部１６ａ上にはコンデンサが接続され、図１２の平面図に示すように平板コンデンサ（第２のコンデンサ）３０と前記中心導体４とにチップインダクタ３１を接続してＬＣ回路を構成している。中心導体５の一端は、平板コンデンサ９の上面の電極と端子電極部１６ｄに接続される。
【０００７】
そして、下ケース１２上に樹脂ケース７が配置される。下ケース１２は、樹脂ケース７の底部の凹部２１に合致する構造となっている。この凹部２１では、接続電極１４ａが露出し下ケース１２とはんだ接続されて、樹脂ケース７と下ケース１２が一体化される。そして、ガーネットフェライト３に直流磁界を印加する永久磁石２を上ケース１に位置決めし、上ケース１と下ケース１２を嵌合させて、面実装可能なアイソレータを構成している。尚、上記抵抗を無くし、他の中心導体と同様に端子電極部を設けて構成すればサーキュレータとなる。また、上記コンデンサ、端子電極部と中心導体端部との接続は、例えば半田付けやスポット溶接により行われる。このように構成して図１１に示す等価回路のアイソレータとしていた。
【０００８】
【発明が解決しようとする課題】
このような非可逆回路素子は用いられる通信システム（例えばＷ−ＣＤＭＡ、ＰＤＣ、ＰＣＳ等）の周波数帯の拡張に対応するため広帯域をカバーする性能が要求される。また、移動体通信の分野では、小型高性能化と低価格化の要求は高まるばかりで、いまや数百μｍ単位での小型化とコンマ数ｄＢ単位での高性能化と更なる廉価化が課題とされるに至っている。
前記のような従来の非可逆回路素子をさらに小型化する場合、平板コンデンサ８，９，１０や、ガーネットフェライト３の寸法を小さくするのはもとより、端子電極部１６ａと接続してＬＣ回路を構成するコンデンサ３０、インダクタ３１も小型のものを使用して構成する必要があった。コンデンサやインダクタを小型にしていくとＱ値が劣化し、非可逆回路素子の挿入損失が大きくなるといった問題や、コンデンサ３０とインダクタ３１との接続方法を十分に考慮しないと接続状態が悪くなったり、ツームストーン現象により素子立ちが生じ、非可逆回路素子として機能しないといった問題があった。
そこで本発明はＬＣ回路を内蔵する非可逆回路素子において、小型化しても電気的特性劣化がなく、前記ＬＣ回路を構成するコンデンサ、インダクタの実装性を向上し、電気的接続の信頼性を高めた非可逆回路素子を提供することを目的とする。
【０００９】
【課題を解決するための手段】
本発明は、フェリ磁性体に複数の中心導体が配された組立体と、前記中心導体の一端とグランド間に配置される複数の第１のコンデンサと、前記中心導体と入力端子及び／又は出力端子間に配置されるＬＣ回路を構成する表面実装型インダクタ及び第２のコンデンサと、前記フェリ磁性体に直流磁界を与える永久磁石と、前記入力端子と前記出力端子が形成された樹脂ケースを備えた非可逆回路素子であって、
前記第１のコンデンサと前記第２のコンデンサとは板状の誘電体基板の主面に電極を形成してなる平板コンデンサであり、
前記表面実装型インダクタが線部と該巻線部の両端部に設けられた二つの鍔状脚部と、前記巻線部に巻回される巻線と、前記鍔状脚部の下面側に設けられ前記巻線の終端部が接続される端子電極を備え、
前記表面実装型インダクタにより前記第１のコンデンサと前記第２のコンデンサを電気的に接続する非可逆回路素子である。
【００１０】
本発明において、ＬＣ回路を構成する第２のコンデンサと表面実装型インダクタの接続を、第１のコンデンサと第２のコンデンサの主面に前記表面実装型インダクタの端子電極を電気的に接続して行うのが好ましい。樹脂ケースには熱可塑性樹脂を壁として第１のコンデンサと第２のコンデンサを収容する凹部が形成されており、前記第１のコンデンサと第２のコンデンサとの間に形成された仕切壁は、前記第１のコンデンサと前記第２のコンデンサの主面よりも低い高さに形成するのが好ましい。
そして、前記仕切壁と連続する凹部壁の一部を切欠いた部分を含み、面実装型インダクタを前記第１のコンデンサ及び第２のコンデンサを収容するそれぞれの凹部の一部と重なる領域に配置するのが好ましい。
本発明においては、前記第１コンデンサ及び第２のコンデンサを一つの誘電体基板の主面に電極を形成してなる平板コンデンサとして構成することも出来る。
【００１１】
また本発明においては、表面実装型インダクタの自己共振周波数は非可逆回路素子の動作周波数よりも高く、かつ２５０ＭＨｚにおけるＱが２７以上とするのが好ましい。この表面実装型インダクタの磁心は、Ａｌを主成分とし、副成分としてＭｎを必須としＣｒ、Ｔｉ、Ｓｉ、Ｓｒの群から選ばれる少なくとも一つを有する非磁性のセラミック材料やＡｌを主成分とし、副成分としてＳｉを必須としＣａ、Ｂａ、Ｔｉ、Ｉｒ、Ｐの群から選ばれる少なくとも一つを有する非磁性のセラミック材料で構成するのも好ましい。
【００１２】
【発明の実施の形態】
本発明の非可逆回路素子用樹脂ケースとこれを用いた非可逆回路素子について、図をもとに以下詳細に説明する。
図１は、本発明の一実施例に掛かる非可逆回路素子の樹脂ケースの平面図であり、図２は中心導体を構成する導体薄板の平面図であり、図３（ａ）はＡ指示部の拡大図であり、図３（ｂ）は部品を実装した状態を示す拡大図であり、図４は図３（ｂ）に開示した非可逆回路素子用樹脂ケースのＡ−Ａ‘断面図であり、図５は本発明の非可逆回路素子の一例を示す分解斜視図である。
【００１３】
図１及び図４に示すように、この樹脂ケース７には第１のコンデンサである平板コンデンサ８、９、１０が収容配置される凹部１３ｂ、１３ｃ、１３ｄと、ＬＣ回路を構成する第２のコンデンサである平板コンデンサ３０が収容配置される凹部１３ｆと、平板コンデンサ１０と並列接続されるダミー抵抗１１が配置される凹部１３ｅと、前記凹部の壁の一部を表面実装型インダクタ３１の連接する２側面を支持するように切りかいた切欠き部１８が形成されている。
樹脂ケース７は、例えば０．１ｍｍ程度のＣｕの導体薄板と液晶ポリマーやポリフェニレンサルファイド等の高耐熱の熱可塑性エンジニアリングプラスチックを一体化してなるものである。前記Ｃｕの導体薄板や前記磁気ヨークには、その表面に銀、銅、金、アルミニウムのうち少なくとも一つを含む金属または合金で電気抵抗率が５．５μΩｃｍ以下、好ましくは３．０μΩｃｍ更に好ましくは１．８μΩｃｍ以下である導電性の高い金属皮膜を形成し、これにより、マイクロ波信号の伝送効率を高め、外部との相互干渉を抑制して損失を低減している。このときの皮膜厚さは０．５〜２５μｍ、好ましくは０．５〜１０μｍ、更に好ましくは１〜８μｍである。そして、前記導体薄板や金属磁性材をフープ状とし、これを金型内に配置して前記熱可塑性エンジニアリングプラスチックを用いて射出成形して形成される。平板コンデンサを収容するための３つの凹部１３ｂ、１３ｃ、１３ｄの底部は、組立体２０が収容される凹部１３ａの底部の導体薄板が露出した共通の接続電極１４ａとつながり、前記平板コンデンサ８，９，１０が一面状に配置され、平板コンデンサの下面の電極と凹部の底部に形成された接続電極１４ａと半田接続される。前記平板コンデンサ３０が収容される凹部１３ｆの底部は、導体薄板が露出して入力端子を形成する端子電極部１６ａとなっている。
【００１４】
組立体２０は、例えば図２に示すように、円板状のシールド板から放射状に３つの中心導体４、５、６が突出した構造の導体薄板を用意し、その導体薄板の円板状部にガーネットフェライト３を配置して、前記３つの中心導体４、５、６を折り曲げて重ねて一体に構成される。そして中心導体４、５の一端は、平板コンデンサ８、９の上面の電極に接続され、中心導体５の一端は、平板コンデンサ１０の上面の電極とダミー抵抗１１と接続される。そして中心導体４は屈曲形成されており、表面実装型インダクタ３１と干渉しないように構成されている。
【００１５】
図３（ａ）（ｂ）に樹脂ケースのＬＣ回路を配置する部分の拡大図を示す。前記凹部１７には、ＬＣ回路を構成する平板コンデンサ３０が配置され、平板コンデンサ３０の一方の電極が端子電極部１６ａにはんだ接続される。そして平板コンデンサ３０と平板コンデンサ８を電気的に接続するように表面実装型インダクタ３１が配置される。平板コンデンサが収容される凹部間の仕切壁５０を平板コンデンサの前記電極面よりも突出しないように形成している。そして、前記平板コンデンサのそれぞれの電極面をそれぞれ実質的に等しい高さとしているので前記表面実装型インダクタ３１は組立時に傾むいたりせずに安定して配置される。また、前記凹部１３ｂの壁の一部を切りかいた切欠き部１８により表面実装型インダクタ３１の連接する２側面を支持するようにし、凹部１３ｆの樹脂壁により他の２側面を支持するようにしているので、表面実装型インダクタ３１がずれたり、素子立ちをすることがなく、電気的接続を信頼性良く行うことが出来る。
【００１６】
図４は平板コンデンサ８、平板コンデンサ３０、表面実装型インダクタ３１を実装した状態のＡ−Ａ’断面図である。表面実装型インダクタ３１は平板コンデンサ８、平板コンデンサ３０の主面に実装されはんだ付けされる。表面実装型インダクタの巻線部は端子電極に対して凹状となっており、はんだが表面実装型インダクタの下面側に回り込むことがない。このため平板コンデンサ８、平板コンデンサ３０をショートするようなはんだブリッジが発生せず、ツームストーン現象も発生しにくく、電気的接続を信頼性良く行うことが出来る。また、中心導体４を屈曲形成して、表面実装型インダクタ３１と干渉しないように構成しているので、はんだ付けの際に表面実装型インダクタに外力を加えて保持する必要なく、非可逆回路素子の構成を簡単に出来る。
【００１７】
図５に示すようにガーネットフェライトを略円板状とし、その一部を中心軸に平行に切断した形状としている。このように構成することで、終端抵抗と接続する中心導体の直流磁界印加方向にガーネットフェライトと重複する部分の長さを他の中心導体よりも短く構成して、電気的特性の一つであるアイソレーション特性を改善するとともに、組立体２０の中心を樹脂ケースの中心近傍とすることで、ＬＣ回路を構成する平板コンデンサ３０を配置する凹部１３ｆを平面的に広くなるように構成した。このため、平板コンデンサ３０のコンデンサ電極面積を広くすることが出来、コンデンサのＱ値を劣化させることなく構成でき、また誘電体基板を適度な厚みをもって構成できるので、その取り扱いが容易である。
【００１８】
図６に表面実装型インダクタ３１の外観斜視図を、図７にその側面図を示す。この表面実装型インダクタ３１は１００５サイズであり、磁心２の巻線部１０１と該巻線部の両端部に設けられた二つの鍔状脚部１０２ａ、１０２ｂと、前記巻線部に巻回される巻線１０３と、前記鍔状脚部の下面側に設けられ前記巻線の終端部１０４ａ、１０４ｂが接続される端子電極１０５ａ、１０５ｂを備える。
磁心２を構成する材料は、アルミナを主成分とする非磁性のセラミック材料が用いられる。例えばＡｌを主成分とし、副成分としてＭｎを必須としＣｒ、Ｔｉ、Ｓｉ、Ｓｒの群から選ばれる少なくとも一つを有する非磁性のセラミック材料や、Ａｌを主成分とし、副成分としてＳｉを必須としＣａ、Ｂａ、Ｔｉ、Ｉｒ、Ｐの群から選ばれる少なくとも一つを有する非磁性のセラミック材料である。具体的には、酸化物換算でＡｌ：８９〜９５ｗｔ％、Ｍｎ：２〜４ｗｔ％、残部がＣｒ、Ｔｉ、Ｓｉ、Ｓｒの群から選ばれる少なくとも一つであり、また、酸化物換算でＡｌ：８５〜８８ｗｔ％、Ｓｉ：８〜１０ｗｔ％、残部がＣａ、Ｂａ、Ｔｉ、Ｉｒ、Ｐの群から選ばれる少なくとも一つのセラミック材料である。
【００１９】
端子電極１０５ａ、１０５ｂはＡｇ、Ｃｕ等の下地電極にＮｉを下地としＳｎ，Ａｇ，Ｃｕ等の合金めっきが施されている。巻線部に巻回される巻線１０３は、線径が数十μｍの導線を用い、その終端部は端子電極１０５ａ、１０５ｂに接続され、巻回される巻線１０３による磁界は、永久磁石２の直流磁界に対して、略直交するようになる。このように構成することで、表面実装型インダクタの自己共振周波数が非可逆回路素子の動作周波数よりも高く、かつ２５０ＭＨｚにおけるＱ値が２７以上の高Ｑ値を得ることができ、もって非可逆回路素子の電気的特性を損ねることがない。
【００２０】
非可逆回路素子用樹脂ケース７の外壁部５１は前記熱可塑性樹脂で形成され、この外壁部５１は中心導体の一端が接続される前記平板コンデンサの電極面よりも高く形成される。そしてその外壁部の対向する２側面に前記導体薄板からなる外部端子１５ａ〜１５ｆを備えるように構成している。
この外部端子は、前記Ｃｕの導体薄板で形成され、この導体薄板と前記熱可塑性樹脂とを射出成形後、フープ状になした導体薄板のリード部（図示せず）を金型で切断、折り曲げ加工して、前記外部端子として形成した。前記外部端子の内、外部端子１５ｂ，１５ｃ，１５ｅ，１５ｆは、前記接続電極１４ａと接続している。
【００２１】
このような樹脂ケースを用いて８００ＭＨｚ対応（ＰＤＣ　周波数８４３ＭＨｚ〜９６０ＭＨｚ）の４ｍｍ角アイソレータを作製した。このアイソレータは、従来のアイソレータと同じく磁気ヨークとして機能する金属ケース（上ケース１、下ケース１２）、永久磁石２、組立体２０、平板コンデンサ８、９、１０、ダミー抵抗１１、樹脂ケース７から構成され、その等価回路は図９に示す従来のものと同様である。中心導体４，５，６が巻回された前記ガーネットフェライト部分でインダクタンスＬ１，Ｌ２，Ｌ３を形成し、平板コンデンサ８，９，１０でコンデンサＣ１，Ｃ２，Ｃ３を形成する。前記コンデンサＣ３に並列接続するダミー抵抗１１（Ｒｔ）を配置し、前記インダクタンスＬ１，Ｌ２，Ｌ３、コンデンサＣ１，Ｃ２，Ｃ３を調整して所望の周波数ｆ０（中心周波数）で動作するアイソレータを構成した。
図８に本発明の一実施例に係るアイソレータと比較例のアイソレータの入力ポートＰ１（外部端子１５ａが対応）―出力ポートＰ２（外部端子１５ｄが対応）間での挿入損失特性の周波数特性を示す。比較例のアイソレータは表面実装型インダクタを１００５タイプの積層型インダクタとしたものであり、他の構成は実施例のものと同一なのでその説明を省く。
本発明のアイソレータでは、その挿入損失のピーク値が０．１５ｄＢ以下であり、通過帯域においても０．２ｄＢ以下であった。一方、比較例のものは、挿入損失のピーク値が０．３５ｄＢ程度であり、通過帯域においても０．４ｄＢ程度であり、本発明のアイソレータと比べ、電気的特性に劣るものであった。
【００２２】
上記実施例においては、第１のコンデンサと第２のコンデンサとをそれぞれ異なる有電体基板で構成したが、図９に示すように一つの誘電体基板の主面に前記第１のコンデンサと第２のコンデンサの電極を形成した平板コンデンサとして構成してもよい。この場合には、第１のコンデンサと第２のコンデンサを仕切る仕切壁は必要としない。表面実装型インダクタは、前記平板コンデンサの電極に接続されるが、予め平板コンデンサと表面実装型インダクタとをはんだ付けして、これを樹脂ケースに実装するのが組み立てを簡略化できて好ましい。平板コンデンサと表面実装型インダクタとをはんだ付けするはんだは、他の部位をはんだ付けするはんだよりも高い温度ではんだ付けされるものを用いれば、表面実装型インダクタの固定を別途行わなくてすむのでより好ましい。
本発明に非可逆回路素子に用いられるはんだはＳｎ−Ａｇ−Ｃｕ系等のＰｂフリーはんだを用いるのがより好ましい。
【００２３】
【発明の効果】
本発明によれば、従来のＬＣ回路を内蔵する非可逆回路素子が抱えていた、いくつかの問題を解消し、すなわち小型化しても電気的特性劣化がなく、前記ＬＣ回路を構成するコンデンサ、インダクタの実装性を向上し、電気的接続の信頼性を高めた非可逆回路素子を得ることができる。
【図面の簡単な説明】
【図１】本発明の一実施例に掛かる非可逆回路素子の樹脂ケースの平面図である。
【図２】中心導体を構成する導体薄板の平面図である。
【図３】（ａ）本発明の一実施例に掛かる非可逆回路素子の樹脂ケースＡ指示部の拡大図であり、（ｂ）は部品を実装した状態を示す拡大図である。
【図４】図３（ｂ）に開示した非可逆回路素子用樹脂ケースのＡ−Ａ‘断面図である。
【図５】本発明の非可逆回路素子の一例を示す分解斜視図である。
【図６】本発明の非可逆回路素子に用いる表面実装型インダクタの外観斜視図である。
【図７】本発明の非可逆回路素子に用いる表面実装型インダクタの正面図である。
【図８】本発明の一実施例に係る非可逆回路素子と従来の非可逆回路素子の挿入損失の周波数特性図である。
【図９】本発明の一実施例に係る非可逆回路素子に用いる平板コンデンサの他の例を示す斜視図である。
【図１０】従来の非可逆回路素子の分解斜視図である。
【図１１】本発明を適用する非可逆回路素子の等価回路図である。
【図１２】従来の非可逆回路素子の部分拡大図である。
【符号の説明】
４、５、６　中心導体
７　樹脂ケース
８、９、１０、３１　平板コンデンサ
１１　ダミー抵抗
１３ｂ、１３ｃ、１３ｄ、１３ｆ　平板コンデンサを配置する凹部
１４ａ　接続電極
１５ａ，１５ｂ，１５ｃ，１５ｄ，１５ｅ，１５ｆ　外部端子
２０　組立体
２２　絶縁部材
３１　表面実装型インダクタ
５０　平板コンデンサが収容される凹部間の仕切壁[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a non-reciprocal circuit device having a non-reciprocal transmission characteristic for a high-frequency signal and a resin case used therefor, and more specifically, is used in a mobile communication system such as a mobile phone, and is generally used for an isolator or a circulator. And a resin case.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, non-reciprocal circuit elements such as isolators and circulators are one of transmission / reception circuit components used in microwave bands and UHF bands for mobile phones, automobile phones, and the like. Generally, isolators and circulators are used for the purpose of preventing damage to an amplifier, and have a function of reducing insertion loss in a signal transmission direction and increasing reverse loss in a reverse direction. Hereinafter, in this specification, an isolator will be described as an example of the non-reciprocal circuit device disclosed in Japanese Patent Application Laid-Open No. 11-308013.
[0003]
FIG. 9 is an exploded perspective view showing an example of a conventional isolator. This isolator includes a metal case (upper case 1, lower case 12) functioning as a magnetic yoke, a permanent magnet 2, an assembly 20, plate capacitors (first capacitors) 8, 9, 10, a dummy resistor 11, and a resin case 7. It is composed of
The assembly 20 prepares a conductor thin plate having a structure in which three center conductors 4, 5, and 6 protrude radially from a disk-shaped shield plate, and a garnet ferrite (ferrimagnetic material) is provided on the disc-shaped portion of the conductor thin plate. 3) are arranged, and the three center conductors 4, 5, 6 are bent and stacked to be integrally formed. At this time, the center conductors 4, 5, and 6 are superposed insulated.
[0004]
The resin case 7 has a circular concave portion 13a for the assembly 20 at the center, and concave portions 13b, 13c, and 13d for the flat plate capacitors around the circular concave portion 13a. Connection electrodes 14a are formed in the bottoms of the recesses 13b, 13c, 13d for the flat capacitor and the recess 13a for the assembly 20. The connection electrode 14a is made of an integral conductor thin plate having a thickness of about 0.1 mm, extends to the side of the resin case, and forms external terminals 15a to 15f. The external terminals 15d to 15f are symmetrically formed on the surfaces facing the external terminals 15a to 15c. Further, terminal electrode portions 16a and 16d to which the center conductor is connected are formed in the resin case. The terminal electrodes 16a and 16d are formed so as to be electrically connected to the external terminals 15a and 15d on the side surfaces. These external terminals, the terminal electrode portions to be connected, and the connection electrodes are formed from the same conductive thin plate.
[0005]
In the concave portions 13b, 13c, 13d of the resin case 7, flat plate capacitors 8, 9, 10 are accommodated and arranged, respectively. This flat plate capacitor is formed by forming electrodes on the upper and lower surfaces of a flat dielectric substrate, and the electrodes on the lower surface and the connection electrodes 14a formed on the bottom of the recess are connected by soldering. A dummy resistor 11 is arranged in the recess 13d together with the plate capacitor 10. One electrode of the dummy resistor 11 is connected to the connection electrode 14a by soldering, and the other electrode is connected to the center conductor 6.
[0006]
Next, the above-described assembly 20 is disposed in the recess 13 a of the resin case 7. At this time, the disk-shaped shield plate of the center conductor is soldered to the connection electrode 14a. Thereby, one end of the center conductor is grounded. One end of the center conductor 4 is connected to an electrode on the upper surface of the plate capacitor 8, and one end of the center conductor 5 is connected to an electrode on the upper surface of the plate capacitor 9 and the terminal electrode portion 16d. Then, a capacitor is connected to the terminal electrode portion 16a, and a chip inductor 31 is connected to the plate capacitor (second capacitor) 30 and the center conductor 4 as shown in the plan view of FIG. ing. One end of the center conductor 5 is connected to the electrode on the upper surface of the plate capacitor 9 and the terminal electrode portion 16d.
[0007]
Then, the resin case 7 is disposed on the lower case 12. The lower case 12 has a structure that matches the concave portion 21 at the bottom of the resin case 7. In the concave portion 21, the connection electrode 14a is exposed and soldered to the lower case 12, so that the resin case 7 and the lower case 12 are integrated. Then, the permanent magnet 2 for applying a DC magnetic field to the garnet ferrite 3 is positioned in the upper case 1, and the upper case 1 and the lower case 12 are fitted to each other to form a surface mountable isolator. It should be noted that a circulator can be obtained if the resistance is eliminated and a terminal electrode portion is provided similarly to the other central conductors. The connection between the capacitor, the terminal electrode portion and the center conductor end portion is performed by, for example, soldering or spot welding. With this configuration, the isolator of the equivalent circuit shown in FIG.
[0008]
[Problems to be solved by the invention]
Such a non-reciprocal circuit device is required to have a performance covering a wide band in order to cope with an extension of a frequency band of a communication system (for example, W-CDMA, PDC, PCS, etc.) to be used. In the field of mobile communications, the demand for compact, high-performance, and low-cost products is only increasing, and now, miniaturization in the order of several hundred μm, performance in the order of a few commas, and further cost reduction are issues. It has been reached.
In order to further reduce the size of the conventional non-reciprocal circuit device as described above, not only the dimensions of the plate capacitors 8, 9, 10 and the garnet ferrite 3 are reduced, but also the LC circuit is configured by connecting to the terminal electrode portion 16a. The capacitor 30 and the inductor 31 need to be configured using small ones. As the size of the capacitor or inductor is reduced, the Q value is degraded, and the insertion loss of the nonreciprocal circuit element is increased. Also, if the connection method between the capacitor 30 and the inductor 31 is not sufficiently considered, the connection state becomes poor. In addition, there has been a problem that the element is raised due to the tombstone phenomenon and does not function as a non-reciprocal circuit element.
Accordingly, the present invention provides a non-reciprocal circuit device having a built-in LC circuit, which does not deteriorate in electrical characteristics even when the device is downsized, improves the mountability of capacitors and inductors constituting the LC circuit, and improves the reliability of electrical connection. And a non-reciprocal circuit device.
[0009]
[Means for Solving the Problems]
The present invention provides an assembly in which a plurality of center conductors are arranged on a ferrimagnetic material, a plurality of first capacitors arranged between one end of the center conductor and a ground, the center conductor and an input terminal and / or an output. A surface mount type inductor and a second capacitor constituting an LC circuit disposed between terminals; a permanent magnet for applying a DC magnetic field to the ferrimagnetic material; and a resin case in which the input terminal and the output terminal are formed. A non-reciprocal circuit element,
The first capacitor and the second capacitor are plate capacitors formed by forming electrodes on a main surface of a plate-shaped dielectric substrate,
The surface-mount type inductor has a wire portion and two flange-shaped legs provided at both ends of the winding portion, a winding wound around the winding portion, and a lower surface side of the flange-shaped leg portion. A terminal electrode provided and connected to a terminal end of the winding,
A nonreciprocal circuit element electrically connecting the first capacitor and the second capacitor by the surface mount inductor.
[0010]
In the present invention, the connection between the second capacitor constituting the LC circuit and the surface-mounted inductor is performed by electrically connecting the terminal electrodes of the surface-mounted inductor to the main surfaces of the first capacitor and the second capacitor. It is preferred to do so. In the resin case, a concave portion that accommodates the first capacitor and the second capacitor is formed using a thermoplastic resin as a wall, and a partition wall formed between the first capacitor and the second capacitor includes: It is preferable that the first capacitor and the second capacitor are formed at a height lower than the main surface.
Then, the surface-mount inductor is disposed in a region overlapping with a part of each of the concave portions accommodating the first capacitor and the second capacitor, including a part in which a part of a concave wall continuous with the partition wall is cut off. Is preferred.
In the present invention, the first capacitor and the second capacitor may be configured as flat plate capacitors having electrodes formed on the main surface of one dielectric substrate.
[0011]
In the present invention, the self-resonant frequency of the surface-mount inductor is preferably higher than the operating frequency of the non-reciprocal circuit device, and the Q at 250 MHz is preferably 27 or more. The magnetic core of this surface mount type inductor is mainly composed of Al, a non-magnetic ceramic material having at least one selected from the group consisting of Cr, Ti, Si and Sr, and Al as a minor component, and Al as a main component. It is also preferable to use a non-magnetic ceramic material having Si as an essential component and having at least one selected from the group consisting of Ca, Ba, Ti, Ir, and P.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The resin case for a non-reciprocal circuit device of the present invention and the non-reciprocal circuit device using the same will be described in detail below with reference to the drawings.
FIG. 1 is a plan view of a resin case of a non-reciprocal circuit device according to one embodiment of the present invention, FIG. 2 is a plan view of a conductor thin plate constituting a center conductor, and FIG. 3B is an enlarged view showing a state where components are mounted, and FIG. 4 is an AA ′ cross-sectional view of the resin case for the non-reciprocal circuit device disclosed in FIG. 3B. FIG. 5 is an exploded perspective view showing an example of the non-reciprocal circuit device of the present invention.
[0013]
As shown in FIGS. 1 and 4, the resin case 7 has recesses 13b, 13c, and 13d in which flat capacitors 8, 9, and 10 as first capacitors are accommodated and arranged, and a second capacitor constituting an LC circuit. A concave portion 13f in which the plate capacitor 30 as a capacitor is accommodated and arranged, a concave portion 13e in which the dummy resistor 11 connected in parallel with the plate capacitor 10 is arranged, and a part of the wall of the concave portion is connected to the surface mount type inductor 31. A cutout portion 18 cut out to support two side surfaces is formed.
The resin case 7 is formed by integrating a conductor thin plate of Cu having a thickness of, for example, about 0.1 mm and a high heat-resistant thermoplastic engineering plastic such as a liquid crystal polymer or polyphenylene sulfide. The Cu conductor thin plate or the magnetic yoke has a metal or alloy containing at least one of silver, copper, gold and aluminum on its surface and an electric resistivity of 5.5 μΩcm or less, preferably 3.0 μΩcm, more preferably A highly conductive metal film having a thickness of 1.8 μΩcm or less is formed, thereby increasing the microwave signal transmission efficiency, suppressing mutual interference with the outside, and reducing loss. At this time, the film thickness is 0.5 to 25 μm, preferably 0.5 to 10 μm, and more preferably 1 to 8 μm. Then, the conductor thin plate or the metal magnetic material is formed into a hoop shape, which is arranged in a mold, and is formed by injection molding using the thermoplastic engineering plastic. The bottoms of the three recesses 13b, 13c, and 13d for accommodating the plate capacitors are connected to a common connection electrode 14a where the conductive thin plate at the bottom of the recess 13a in which the assembly 20 is accommodated is exposed. , 10 are arranged in a plane, and are connected by soldering to the electrodes on the lower surface of the plate capacitor and the connection electrodes 14a formed on the bottom of the concave portion. The bottom of the concave portion 13f in which the flat capacitor 30 is accommodated is a terminal electrode portion 16a where the conductive thin plate is exposed to form an input terminal.
[0014]
As shown in FIG. 2, for example, as shown in FIG. 2, a conductor thin plate having a structure in which three center conductors 4, 5, and 6 protrude radially from a disk-shaped shield plate is prepared, and a disc-shaped portion of the conductor thin plate is prepared. A garnet ferrite 3 is disposed on the center, and the three center conductors 4, 5, and 6 are bent and overlapped to be integrally formed. One end of each of the center conductors 4 and 5 is connected to an electrode on the upper surface of the plate capacitors 8 and 9, and one end of the center conductor 5 is connected to an electrode on the upper surface of the plate capacitor 10 and the dummy resistor 11. The center conductor 4 is bent so as not to interfere with the surface mount type inductor 31.
[0015]
FIGS. 3A and 3B are enlarged views of a portion where the LC circuit of the resin case is arranged. A flat capacitor 30 constituting an LC circuit is arranged in the concave portion 17, and one electrode of the flat capacitor 30 is connected to the terminal electrode portion 16a by soldering. Then, a surface mount inductor 31 is arranged so as to electrically connect the plate capacitor 30 and the plate capacitor 8. The partition wall 50 between the recesses in which the flat capacitor is accommodated is formed so as not to protrude beyond the electrode surface of the flat capacitor. Since the respective electrode surfaces of the plate capacitor have substantially the same height, the surface-mounted inductor 31 is stably disposed without being inclined at the time of assembly. In addition, the two side surfaces connected to the surface mount type inductor 31 are supported by the cutout portion 18 in which a part of the wall of the concave portion 13b is cut, and the other two side surfaces are supported by the resin wall of the concave portion 13f. Therefore, the electrical connection can be performed with high reliability without causing the surface-mount type inductor 31 to shift or stand up.
[0016]
FIG. 4 is a cross-sectional view taken along the line AA 'in a state where the plate capacitor 8, the plate capacitor 30, and the surface-mount inductor 31 are mounted. The surface mount type inductor 31 is mounted on the main surfaces of the plate capacitors 8 and 30 and soldered. The winding portion of the surface mount inductor is concave with respect to the terminal electrode, so that the solder does not flow to the lower surface side of the surface mount inductor. Therefore, a solder bridge that short-circuits the plate capacitor 8 and the plate capacitor 30 does not occur, the tombstone phenomenon hardly occurs, and the electrical connection can be performed with high reliability. Further, since the center conductor 4 is formed so as to be bent so as not to interfere with the surface mount type inductor 31, there is no need to apply and hold an external force to the surface mount type inductor at the time of soldering. Can be simplified.
[0017]
As shown in FIG. 5, the garnet ferrite is formed in a substantially disk shape and a part thereof is cut in parallel with the central axis. With this configuration, the length of the portion overlapping the garnet ferrite in the direction of applying the DC magnetic field of the center conductor connected to the terminating resistor is made shorter than that of the other center conductors, which is one of the electrical characteristics. By improving the isolation characteristics and making the center of the assembly 20 close to the center of the resin case, the concave portion 13f in which the flat plate capacitor 30 constituting the LC circuit is disposed is made wider in a plane. For this reason, the capacitor electrode area of the flat plate capacitor 30 can be enlarged, the capacitor can be configured without deteriorating the Q value, and the dielectric substrate can be configured with an appropriate thickness, so that the handling is easy.
[0018]
FIG. 6 is an external perspective view of the surface mount inductor 31, and FIG. 7 is a side view thereof. The surface-mount type inductor 31 has a size of 1005, and is wound around the winding part 101 of the magnetic core 2 and two flange-shaped legs 102a and 102b provided at both ends of the winding part. And terminal electrodes 105a and 105b provided on the lower surface side of the flange-shaped leg and connected to terminal portions 104a and 104b of the winding.
As a material forming the magnetic core 2, a non-magnetic ceramic material containing alumina as a main component is used. For example, a non-magnetic ceramic material having Al as a main component and at least one selected from the group consisting of Cr, Ti, Si, and Sr and Mn as a sub-component, or Al as a main component and Si as a sub-component And a non-magnetic ceramic material having at least one selected from the group consisting of Ca, Ba, Ti, Ir, and P. Specifically, Al is 89 to 95 wt% in terms of oxide, Mn is 2 to 4 wt%, and the balance is at least one selected from the group consisting of Cr, Ti, Si, and Sr. : 85 to 88 wt%, Si: 8 to 10 wt%, and the balance is at least one ceramic material selected from the group consisting of Ca, Ba, Ti, Ir, and P.
[0019]
The terminal electrodes 105a and 105b are made of a base electrode of Ag, Cu, or the like, and plated with an alloy of Sn, Ag, Cu, or the like using Ni as a base. The winding 103 wound around the winding part uses a conducting wire having a wire diameter of several tens of μm, and its end is connected to the terminal electrodes 105a and 105b. The two DC magnetic fields are substantially orthogonal to each other. With this configuration, the self-resonant frequency of the surface mount inductor is higher than the operating frequency of the non-reciprocal circuit device, and the Q value at 250 MHz can be a high Q value of 27 or more. It does not impair the electrical characteristics of the device.
[0020]
The outer wall 51 of the non-reciprocal circuit device resin case 7 is formed of the thermoplastic resin, and the outer wall 51 is formed higher than the electrode surface of the flat plate capacitor to which one end of the center conductor is connected. And, it is configured such that external terminals 15a to 15f made of the conductor thin plate are provided on two opposing side surfaces of the outer wall portion.
The external terminal is formed of the Cu conductor thin plate. After the conductor thin plate and the thermoplastic resin are injection molded, a lead portion (not shown) of the hoop-shaped conductor thin plate is cut and bent by a mold. It was processed to form the external terminal. Among the external terminals, the external terminals 15b, 15c, 15e, and 15f are connected to the connection electrode 14a.
[0021]
Using such a resin case, a 4 mm square isolator corresponding to 800 MHz (PDC frequency 843 MHz to 960 MHz) was manufactured. This isolator is composed of a metal case (upper case 1, lower case 12), a permanent magnet 2, an assembly 20, plate capacitors 8, 9, 10, a dummy resistor 11, and a resin case 7 which function as a magnetic yoke as in the conventional isolator. The equivalent circuit is the same as the conventional one shown in FIG. The garnet ferrite portions around which the center conductors 4, 5, and 6 are wound form inductances L1, L2, and L3, and the plate capacitors 8, 9, and 10 form capacitors C1, C2, and C3. A dummy resistor 11 (Rt) connected in parallel to the capacitor C3 is arranged, and the inductances L1, L2, L3 and the capacitors C1, C2, C3 are adjusted to constitute an isolator operating at a desired frequency f0 (center frequency). .
FIG. 8 shows frequency characteristics of insertion loss characteristics between the input port P1 (corresponding to the external terminal 15a) and the output port P2 (corresponding to the external terminal 15d) of the isolator according to the embodiment of the present invention and the isolator of the comparative example. . In the isolator of the comparative example, the surface-mount type inductor is a 1005 type laminated inductor, and the other configuration is the same as that of the embodiment.
In the isolator of the present invention, the peak value of the insertion loss was 0.15 dB or less, and also 0.2 dB or less in the pass band. On the other hand, in the case of the comparative example, the peak value of the insertion loss was about 0.35 dB, and even in the pass band, it was about 0.4 dB, which was inferior to the isolator of the present invention in electrical characteristics.
[0022]
In the above-described embodiment, the first capacitor and the second capacitor are formed of different conductive substrates, respectively, but as shown in FIG. 9, the first capacitor and the second capacitor are formed on the main surface of one dielectric substrate. It may be configured as a flat plate capacitor in which electrodes of two capacitors are formed. In this case, a partition for separating the first capacitor and the second capacitor is not required. The surface mount inductor is connected to the electrode of the flat capacitor, and it is preferable to solder the flat capacitor and the surface mount inductor in advance and mount them on a resin case because assembly can be simplified. If the solder used to solder the flat-plate capacitor and the surface-mounted inductor is soldered at a higher temperature than the solder used to solder the other parts, it is not necessary to fix the surface-mounted inductor separately. More preferred.
The solder used for the non-reciprocal circuit device in the present invention is more preferably a Pb-free solder such as Sn-Ag-Cu.
[0023]
【The invention's effect】
According to the present invention, the conventional non-reciprocal circuit device having a built-in LC circuit solves several problems, namely, even if the size is reduced, there is no electrical characteristic degradation, the capacitor constituting the LC circuit, It is possible to obtain a non-reciprocal circuit device in which the mountability of the inductor is improved and the reliability of the electrical connection is improved.
[Brief description of the drawings]
FIG. 1 is a plan view of a resin case of a non-reciprocal circuit device according to one embodiment of the present invention.
FIG. 2 is a plan view of a conductor thin plate constituting a central conductor.
FIG. 3A is an enlarged view of a resin case A indicating portion of the non-reciprocal circuit device according to one embodiment of the present invention, and FIG. 3B is an enlarged view showing a state where components are mounted.
FIG. 4 is a cross-sectional view taken along the line AA ′ of the resin case for the non-reciprocal circuit device disclosed in FIG. 3 (b).
FIG. 5 is an exploded perspective view showing an example of the non-reciprocal circuit device of the present invention.
FIG. 6 is an external perspective view of a surface mount inductor used for the non-reciprocal circuit device of the present invention.
FIG. 7 is a front view of a surface mount inductor used for the non-reciprocal circuit device of the present invention.
FIG. 8 is a frequency characteristic diagram of insertion loss of the nonreciprocal circuit device according to one embodiment of the present invention and a conventional nonreciprocal circuit device.
FIG. 9 is a perspective view showing another example of the plate capacitor used for the non-reciprocal circuit device according to one embodiment of the present invention.
FIG. 10 is an exploded perspective view of a conventional non-reciprocal circuit device.
FIG. 11 is an equivalent circuit diagram of a non-reciprocal circuit device to which the present invention is applied.
FIG. 12 is a partially enlarged view of a conventional nonreciprocal circuit device.
[Explanation of symbols]
4, 5, 6 Center conductor 7 Resin cases 8, 9, 10, 31 Plate capacitor 11 Dummy resistor 13b, 13c, 13d, 13f Concave portion 14a for placing plate capacitor Connection electrodes 15a, 15b, 15c, 15d, 15e, 15f External Terminal 20 Assembly 22 Insulating member 31 Surface mount type inductor 50 Partition wall between recesses for accommodating plate capacitors

Claims

An assembly in which a plurality of center conductors are arranged on a ferrimagnetic body; a plurality of first capacitors arranged between one end of the center conductor and a ground; and an arrangement arranged between the center conductor and an input terminal and / or an output terminal A non-reciprocal circuit comprising a surface-mounted inductor and a second capacitor constituting an LC circuit to be provided, a permanent magnet for applying a DC magnetic field to the ferrimagnetic material, and a resin case in which the input terminal and the output terminal are formed. An element,
The first capacitor and the second capacitor are plate capacitors formed by forming electrodes on a main surface of a plate-shaped dielectric substrate,
The surface mount type inductor includes a winding portion, two flange-shaped legs provided at both ends of the winding portion, a winding wound around the winding portion, and a lower surface side of the flange-shaped leg portion. A terminal electrode provided to the end of the winding is connected,
A non-reciprocal circuit device, wherein the first capacitor and the second capacitor are electrically connected by the surface mount inductor.

The non-reciprocal circuit device according to claim 1, wherein main surfaces of the first capacitor and the second capacitor are electrically connected to terminal electrodes of the surface-mount inductor.

In the resin case, a concave portion that accommodates the first capacitor and the second capacitor is formed by using a thermoplastic resin as a wall, and a partition wall formed between the first capacitor and the second capacitor is formed by the second capacitor. 3. The non-reciprocal circuit device according to claim 2, wherein the non-reciprocal circuit device is formed at a height lower than main surfaces of the first capacitor and the second capacitor. 4.

A surface mount type inductor may be arranged in a region including a part where a part of a concave wall continuous with the partition wall is cut off and overlapping a part of each concave part accommodating the first capacitor and the second capacitor. The non-reciprocal circuit device according to claim 1, wherein:

2. The non-reciprocal circuit device according to claim 1, wherein the first capacitor and the second capacitor are flat plate capacitors each having an electrode formed on a main surface of one dielectric substrate.

6. The non-reciprocal circuit device according to claim 1, wherein the self-resonant frequency of the surface mount type inductor is higher than the operating frequency of the non-reciprocal circuit device, and the Q value at 250 MHz is 27 or more. .

The magnetic core of the surface mount inductor is made of a non-magnetic ceramic material containing Al as a main component, Mn as an auxiliary component, and at least one selected from the group consisting of Cr, Ti, Si, and Sr. The non-reciprocal circuit device according to claim 1.

The magnetic core of the surface mount type inductor is made of a nonmagnetic ceramic material containing Al as a main component, Si as an essential component, and at least one selected from the group consisting of Ca, Ba, Ti, Ir, and P. The non-reciprocal circuit device according to claim 1.