JP2004297268A - Double resonance antenna structure and communication apparatus having the same - Google Patents

Double resonance antenna structure and communication apparatus having the same Download PDF

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JP2004297268A
JP2004297268A JP2003084377A JP2003084377A JP2004297268A JP 2004297268 A JP2004297268 A JP 2004297268A JP 2003084377 A JP2003084377 A JP 2003084377A JP 2003084377 A JP2003084377 A JP 2003084377A JP 2004297268 A JP2004297268 A JP 2004297268A
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radiation electrode
electrode
substrate
parasitic
ground
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JP3922200B2 (en
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Kengo Onaka
健吾 尾仲
Hitoshi Sato
仁 佐藤
Takashi Ishihara
尚 石原
Shoji Nagumo
正二 南雲
Kazuya Kawabata
一也 川端
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Murata Manufacturing Co Ltd
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Murata Manufacturing Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To easily improve the antenna characteristics and miniaturize an antenna. <P>SOLUTION: A feed radiation electrode 2 and a non-feed radiation electrode 3 have main surfaces 2M, 3M with a space on a board surface 4a, respectively. The main surfaces 2M, 3M are adjacently laid in the horizontal direction with a space between them. Grounding electrodes 2G, 3G are formed to extend from the ends Egs of the main surfaces 2M, 3M at the shorting connection side. The grounding electrode 2G extends from the feed radiation electrode 2 to the non-feed radiation electrode 3 with the extending top end connected to a board at the electrode 3. The grounding electrode 3G extends from the non-feed radiation electrode 3 to the feed radiation electrode 2 with the extending top end connected to a board at the electrode 2. The grounding electrodes 2G, 3G have their electrode surfaces opposed to each other through a space. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、無線通信を行うための複共振アンテナ構造およびそれを備えた通信機に関するものである。
【０００２】
【背景技術】
図１３には複共振アンテナ構造の一例（特許文献１参照）が示されている。この複共振アンテナ構造４０では、２つの放射電極４１，４２が互いに間隔を介して並設されている。これら放射電極４１，４２はそれぞれＬ字形状と成しており、放射電極４１は、基板４３と間隔を介して配置されている主面部４１ａと、この主面部４１ａと基板４３間を接続する接続部４１ｂとを有して構成され、放射電極４２も同様に主面部４２ａと接続部４２ｂを有して構成されている。主面部４１ａ，４２ａと、基板４３との間には誘電体（テフロン（登録商標））４４が配設されている。
【０００３】
基板４３はグランドと見なされることから、放射電極４１，４２の各接続部４１ｂ，４２ｂはそれぞれ主面部４１ａ，４２ａをグランドに接地させる短絡部として機能する。また、放射電極４１の接続部４１ｂは、給電線４５を介して、例えば通信機の通信用の高周波回路４６に接続されており、放射電極４１は給電放射電極として機能する。さらに、放射電極４２は高周波回路４６に接続されていない無給電放射電極として機能する。この無給電放射電極４２は、給電放射電極４１と電磁結合して複共振状態を作り出すように形成されている。
【０００４】
例えば、高周波回路４６から給電放射電極４１に通信用の信号が供給されると、その通信用の信号に基づいて給電放射電極４１は励振し、これにより、信号の通信が行われる（つまり、給電放射電極４１はアンテナ動作を行う）。また、無給電放射電極４２は、給電放射電極４１との電磁結合によって、その給電放射電極４１の励振に伴って励振し、給電放射電極４１と複共振状態を作り出しながらアンテナ動作を行う。この複共振状態によって、通信の周波数帯の広帯域化を図ることができたり、複数の周波数帯での通信が可能となる。
【０００５】
図１４には別の複共振アンテナ構造の例（特許文献２参照）が示されている。この複共振アンテナ構造５０では、基板５１上に、給電放射電極５２の主面部５２ａと、無給電放射電極５３の主面部５３ａとが互いに間隔を介して上下方向に配設されている。なお、図１４中の符号５２ｂ，５３ｂは、それぞれ、給電放射電極５２、無給電放射電極５３を基板（グランド）５１に接地させるための短絡部を示している。また、符号５４は給電放射電極５１を例えば通信機の高周波回路（図示せず）に接続させるための給電線を示している。
【０００６】
この複共振アンテナ構造５０においても、複共振アンテナ構造４０と同様に、給電放射電極５２と無給電放射電極５３は電磁結合しており、例えば、高周波回路から供給された通信用の信号に基づいて、給電放射電極５２が励振してアンテナ動作を行うと同時に、電磁結合によって無給電放射電極５３も励振し、当該給電放射電極５２と無給電放射電極５３は複共振状態を作り出しながらアンテナ動作を行う。
【０００７】
【特許文献１】
特開平１−２３１４０４号公報
【特許文献２】
特開平６−２３２６２５号公報
【０００８】
【発明が解決しようとする課題】
図１３に示す構成では、給電放射電極４１と、無給電放射電極４２とは基板面に沿う方向（水平方向）に間隔を介して並設されている。つまり、２つの放射電極４１，４２を横並びさせなければならないので、放射電極４１，４２を配置するための基板の面積を広く必要とするという問題がある。
【０００９】
また、通信機の仕様などによって、アンテナ形成領域の広さ（つまり、給電放射電極４１および無給電放射電極４２を配置できる基板面積）が限られている場合には、その限られた面積の中で、給電放射電極４１と無給電放射電極４２を並設しなければならないので、給電放射電極４１と無給電放射電極４２の大きさが小さくなってしまい、アンテナ利得が悪くなったり、帯域幅が狭くなるというようなアンテナ特性の劣化が起こり易くなるという問題がある。
【００１０】
さらに、給電放射電極４１と無給電放射電極４２間の電磁結合量の調整が難しいという問題がある。また、そのために、給電放射電極４１と無給電放射電極４２間の電磁結合量が製品によってばらつき、これにより、製品間でアンテナ特性がばらつくという問題も発生する。
【００１１】
図１４に示す構成では、アンテナ形成領域の広さが規制されている場合に、図１３に示す構成に比べて、放射電極５２，５３の主面部５２ａ，５３ａを大きく形成することはできるが、次に示すような問題が発生する。例えば、放射電極がグランドに近いと、グランドの影響を受けてアンテナ特性が悪化するので、放射電極の配置の高さ制限がある場合には、下側の給電放射電極５２が基板（グランド）５１に近くなり、アンテナ特性が悪化し易いという問題が発生する。
【００１２】
また、図１４に示す構成においても、図１３の構成と同様に、給電放射電極５２と無給電放射電極５３間の電磁結合量の調整が難しいという問題や、その電磁結合量調整の難しさによって、製品によって給電放射電極５２と無給電放射電極５３間の電磁結合量がばらつき、これにより、製品間でアンテナ特性がばらつくという問題が発生する。
【００１３】
本発明は上記課題を解決するために成されたものであり、その目的は、給電放射電極と無給電放射電極間の電磁結合量の調整が容易となって良好な複共振状態を簡単に得ることができ、また、優れたアンテナ特性を持つ複共振アンテナ構造を提供することにある。
【００１４】
【課題を解決するための手段】
上記目的を達成するために、この発明は次に示す構成をもって前記課題を解決するための手段としている。すなわち、この発明は、複共振状態を作り出す給電放射電極と無給電放射電極が互いに間隔を介してグランドと等価な基板に配設されている複共振アンテナ構造であって、給電放射電極と無給電放射電極は、それぞれ、基板面と間隔を介して配置される主面部を有し、これら給電放射電極の主面部と、無給電放射電極の主面部とは互いに水平方向に間隔を介して隣接並設され、当該給電放射電極と無給電放射電極の各主面部のショート接続側となる端縁部分から、それぞれ、伸設して基板に接続する接地用電極部位が設けられ、その給電放射電極の接地用電極部位は当該給電放射電極側から無給電放射電極側に伸び当該伸長先端部が無給電放射電極側の基板部分に接続され、また、無給電放射電極の接地用電極部位は当該無給電放射電極側から給電放射電極側に、給電放射電極の接地用電極部位と間隔を介し近接配置しながら伸び当該伸長先端部が給電放射電極側の基板部分に接続されており、給電放射電極と無給電放射電極の各接地用電極部位は、基板との接続部から主面部との連接部に至るまでの経路の一部が添設されていることを特徴としている。また、この発明の通信機は、この発明において特徴的な構成を持つ複共振アンテナ構造が設けられていることを特徴としている。
【００１５】
【発明の実施の形態】
以下に、この発明に係る実施形態例を図面に基づいて説明する。
【００１６】
図１（ａ）には本発明に係る複共振アンテナ構造の第１実施形態例が模式的な斜視図により示され、図１（ｂ）には図１（ａ）のＡ−Ａ部分から見た模式的な拡大図である。この複共振アンテナ構造１は、複共振状態を作り出す給電放射電極２と無給電放射電極３が、グランドと見なされる基板４（例えば通信機の回路基板）に配設されて成るものである。
【００１７】
この第１実施形態例では、給電放射電極２と無給電放射電極３は、それぞれ、基板４の表面（基板面）４ａと間隔を介して配置される主面部２Ｍ，３Ｍを有すると共に、主面部２Ｍ，３Ｍのショート接続側となる端縁部分Ｅｇｓに連接している接地用電極部位２Ｇ，３Ｇを有している。
【００１８】
この第１実施形態例では、基板４は長方形状と成しており、給電放射電極２と無給電放射電極３の各主面部２Ｍ，３Ｍは、その長方形状の基板４の端部に、当該基板４の短辺に沿う水平方向ｘに間隔を介し隣接並設されている。それら給電放射電極２と無給電放射電極３の各主面部２Ｍ，３Ｍにおいて、基板短辺に近い側の端縁部分Ｅｇｓがショート接続側の端縁部分となっており、これら各主面部２Ｍ，３Ｍの端縁部分Ｅｇｓからそれぞれ接地用電極部位２Ｇ，３Ｇが伸長形成されている。
【００１９】
図２には図１（ａ）のａ方向から見た接地用電極部位２Ｇ，３Ｇが模式的に示されている。この図に示されるように、無給電放射電極３の接地用電極部位３Ｇは、無給電放射電極３側から給電放射電極２側に向けて伸び当該伸長先端部が給電放射電極２側の基板４の短辺側端縁部分に接続されている。また、給電放射電極２の接地用電極部位２Ｇは、無給電放射電極３の接地用電極部位３Ｇよりも基板内側（奥側）に接地用電極部位３Ｇと間隔を介し近接配置されており、当該接地用電極部位２Ｇは、給電放射電極２側から無給電放射電極３側に伸び当該伸長先端部が無給電放射電極３側の基板４の短辺側端縁部分に接続されている。
【００２０】
それら給電放射電極２と無給電放射電極３の各接地用電極部位２Ｇ，３Ｇは、基板４との接続部Ｐ２ｇ，Ｐ３ｇから主面部２Ｍ，３Ｍとの連接部Ｐ２ｍ，Ｐ３ｍに至るまでの経路Ｋ２，Ｋ３の一部が添設されている。つまり、給電放射電極２と無給電放射電極３の各接地用電極部位２Ｇ，３Ｇは、互いに電極面の一部を間隔を介し対向させて配置されている。これにより、その接地用電極部位２Ｇ，３Ｇ間の間隙には容量が生じる。
【００２１】
ところで、この第１実施形態例では、給電放射電極２の接地用電極部位２Ｇは基板４（グランド）に接続すると共に、例えば通信機の通信用の高周波回路６に接続される（図１（ａ）参照）。つまり、基板４の表面には、高周波回路６に接続する給電電極（図示せず）が形成され、給電放射電極２の接地用電極部位２Ｇは、その基板４上の給電電極に直接的に接続する構成であり、給電放射電極２は直接給電タイプの放射電極となっている。なお、給電放射電極２は非接触給電タイプ（容量給電タイプ）の放射電極としてもよい。この場合には、給電電極と、給電放射電極２の設定の給電部位とは間隔を介し配置され、給電放射電極２は給電電極との電磁界結合により高周波回路６と給電電極を介して接続される。
【００２２】
例えば、高周波回路６から給電放射電極２の接地用電極部位２Ｇに通信用の信号が供給されると、その信号は接地用電極部位２Ｇから主面部２Ｍに伝達され、これにより、給電放射電極２は励振してアンテナ動作を行う。また、この第１実施形態例では、無給電放射電極３は給電放射電極２と電磁結合する構成となっており、この電磁結合によって、無給電放射電極３は給電放射電極２の励振に伴って励振し、これにより、給電放射電極２と無給電放射電極３は複共振状態を作り出す。この給電放射電極２と無給電放射電極３の複共振状態が、良好なアンテナ特性を得ることができる適切な状態となるためには、給電放射電極２と無給電放射電極３の電磁結合量の調整（制御）が重要である。
【００２３】
一般的には、給電放射電極２と無給電放射電極３の各主面部２Ｍ，３Ｍ間の間隔を調整することで、給電放射電極２と無給電放射電極３の電磁結合量の調整が行われる。しかし、主面部２Ｍ，３Ｍは電波の通信動作を主に担う部分であることから、その電磁結合量の調整手法では、主面部２Ｍ，３Ｍ間の間隔を僅かに可変しただけでアンテナ特性が大きく変化してしまうため、アンテナ特性が良好となるように電磁結合量を高精度に調整することは難しかった。
【００２４】
本発明者は、給電放射電極の主面部とグランド間を接続している部位（この第１実施形態例では接地用電極部位２Ｇ）と、無給電放射電極の主面部とグランド間を接続している部位（この第１実施形態例では接地用電極部位３Ｇ）との間の容量を調整することで給電放射電極と無給電放射電極の電磁結合量を調整できることに着目した。つまり、この第１実施形態例では、給電放射電極２と無給電放射電極３の各接地用電極部位２Ｇ，３Ｇ間の容量を、給電放射電極２と無給電放射電極３間の電磁結合量を調整する結合量調整部として機能させることとした。
【００２５】
このため、この第１実施形態例では、より容易に電磁結合量の調整を行うことができるように、給電放射電極２と無給電放射電極３の各接地用電極部位２Ｇ，３Ｇが互いに電極面の一部を間隔を介して対向させる構成とした。これにより、給電放射電極２と無給電放射電極３の各接地用電極部位２Ｇ，３Ｇ間の容量は、図３（ｂ）のモデル図に示されるように接地用電極部位２Ｇ，３Ｇの電極面が対向せずに横並びしている従来の構成よりも、図３（ａ）のモデル図に示されるような第１実施形態例の構成（つまり、各接地用電極部位２Ｇ，３Ｇが互いに電極面の一部を間隔を介して対向している構成）を備えた方が、大きくなる。このように接地用電極部位２Ｇ，３Ｇ間の容量を大きくしたので、その接地用電極部位２Ｇ，３Ｇ間の容量が給電放射電極２と無給電放射電極３間の電磁結合量に関与する度合いが大きくなる。また、容量増加によって容量可変範囲が広がるために、その容量を利用した給電放射電極２と無給電放射電極３間の電磁結合量の可変範囲も拡大する。これらのことと、電磁結合量調整のために主面部２Ｍ，３Ｍの形状等を変更しなくて済むこととによって、接地用電極部位２Ｇ，３Ｇ間の容量を利用することにより、給電放射電極２と無給電放射電極３間の電磁結合量の調整が容易となる。
【００２６】
ここで、接地用電極部位２Ｇ，３Ｇ間の間隔をｄとし、接地用電極部位２Ｇ，３Ｇ間の誘電率をεとし、接地用電極部位２Ｇ，３Ｇの対向面積をＳとした場合に、接地用電極部位２Ｇ，３Ｇ間の容量Ｃは数式（１）に表すことができる。
【００２７】
Ｃ＝ε×（Ｓ／ｄ）・・・・・（１）
【００２８】
数式（１）からも分かるように、接地用電極部位２Ｇ，３Ｇの対向面積Ｓを増加すれば、接地用電極部位２Ｇ，３Ｇ間の容量Ｃを増加させることができる。しかし、仕様などによってアンテナ形成領域の広さや高さが制限される場合があり、この場合には接地用電極部位２Ｇ，３Ｇの大きさに限界があるので、接地用電極部位２Ｇ，３Ｇの対向面積Ｓの調整だけでは要求の容量Ｃ（つまり、給電放射電極２と無給電放射電極３の複共振状態が良好となる電磁結合量に対応する容量）を得ることができないことがある。このことを考慮して、この第１実施形態例では、接地用電極部位２Ｇ，３Ｇ間に誘電体７を介設することで、接地用電極部位２Ｇ，３Ｇ間が空隙である場合よりも接地用電極部位２Ｇ，３Ｇ間の誘電率εを高めて、接地用電極部位２Ｇ，３Ｇ間の容量Ｃを大きくできる構成となっている。
【００２９】
なお、もちろん、接地用電極部位２Ｇ，３Ｇ間に誘電体７を介設しなくとも接地用電極部位２Ｇ，３Ｇ間の容量Ｃを要求に合った容量とすることができる場合には、接地用電極部位２Ｇ，３Ｇ間に誘電体７を設けなくともよい。
【００３０】
接地用電極部位２Ｇ，３Ｇ間の容量Ｃの調整は、接地用電極部位２Ｇ，３Ｇの対向面積Ｓの調整や、接地用電極部位２Ｇ，３Ｇ間の誘電率εの調整だけでなく、接地用電極部位２Ｇ，３Ｇ間の間隔ｄの調整によっても行うことができる。しかし、その間隔ｄを広げようとすると、次に示すような問題が発生する虞がある。
【００３１】
その問題とは、例えば仕様などによってアンテナ形成領域の広さが規制されている場合に生じるものである。つまり、給電放射電極２と無給電放射電極３の各主面部２Ｍ，３Ｍは面積が広いほうがアンテナ効率を向上させることができるので、アンテナ形成領域の広さが規制されている場合にはその限られたアンテナ形成領域の中で、できるだけ各主面部２Ｍ，３Ｍを大きく形成しようとする。このため、例えば図１（ａ）に示す各主面部２Ｍ，３Ｍの開放端側の端縁位置Ｅｋは必然的に定まってしまう。このような状況の中で、接地用電極部位２Ｇ，３Ｇ間の間隔ｄを広げるために、例えば、給電放射電極２のショート接続側となる端縁Ｅｇｓおよび接地用電極部位２Ｇの形成位置を基板４の内側に移動すると、給電放射電極２の主面部２Ｍの面積が狭くなる。これにより、アンテナ効率を低下させてしまう。
【００３２】
このため、アンテナ効率を考慮すると、接地用電極部位２Ｇ，３Ｇ間の間隔ｄを大きく広げることは好ましくなく、このために、接地用電極部位２Ｇ，３Ｇ間の間隔ｄがほぼ定まってしまう場合がある。この場合には、例えば、間隔ｄを広げて接地用電極部位２Ｇ，３Ｇ間の容量Ｃを小さくすることはできない。そこで、例えば、給電放射電極２の接地用電極部位２Ｇと、無給電放射電極３の接地用電極部位３Ｇとのうちの一方又は両方に、図４（ａ）に示されるような非電極部である孔部１１や、図４（ｂ）に示されるような非電極部である切り欠き１２を形成する。これにより、接地用電極部位２Ｇ，３Ｇの対向面積Ｓが減少する。これにより、接地用電極部位２Ｇ，３Ｇ間の間隔ｄを広げることなく、接地用電極部位２Ｇ，３Ｇ間の容量Ｃを小さくすることができる。
【００３３】
また、接地用電極部位２Ｇ，３Ｇ間に配置されている誘電体７に孔部などを形成し、これにより、誘電体７の実質的な誘電率εを低下させることで、接地用電極部位２Ｇ，３Ｇ間の間隔ｄを広げることなく、接地用電極部位２Ｇ，３Ｇ間の容量Ｃを小さくすることもできる。なお、もちろん、接地用電極部位２Ｇ，３Ｇに非電極部を形成することと、誘電体７に孔部などを形成することとを組み合わせて、接地用電極部位２Ｇ，３Ｇ間の容量Ｃを小さくしてもよいものである。
【００３４】
この第１実施形態例では、給電放射電極２と無給電放射電極３の複共振状態が良好なアンテナ特性を得ることができる適切な状態となるように、接地用電極部位２Ｇ，３Ｇ間の容量Ｃの調整（つまり、給電放射電極２と無給電放射電極３の電磁結合量の調整）を実験やシミュレーション等により行って、接地用電極部位２Ｇ，３Ｇの対向面積Ｓと接地用電極部位２Ｇ，３Ｇ間の誘電率εと接地用電極部位２Ｇ，３Ｇ間の間隔ｄがそれぞれ設定されている。
【００３５】
この第１実施形態例では、給電放射電極２と無給電放射電極３は、上記のようにアンテナ特性が良好となる複共振状態を作り出すことで、複数の周波数帯での通信が可能となっている。つまり、給電放射電極２と無給電放射電極３がそれぞれ持つ複数の共振周波数のうち、最も低い共振周波数（基本周波数）を利用した基本モードの通信動作と、その基本周波数よりも高い共振周波数（高次周波数）を利用した高次モードの通信動作とが可能となっている。
【００３６】
ここでは、その基本モードの通信動作による周波数帯と、高次モードの通信動作による周波数帯とがそれぞれ設定の周波数帯となるように、給電放射電極２と無給電放射電極３のそれぞれのインピーダンス（電気長）が調整されて給電放射電極２と無給電放射電極３のそれぞれの基本周波数と高次周波数が調整されている。この第１実施形態例では、給電放射電極２と無給電放射電極３の各主面部２Ｍ，３Ｍの小型化を図りながら、設定の基本周波数および高次周波数を得ることができるように、図１（ａ）に示されるように、各主面部２Ｍ，３Ｍの基板側には誘電体８が設けられている。つまり、誘電体８による波長短縮効果により、誘電体８を設ける場合には、誘電体８を設けない場合と比べて、各主面部２Ｍ，３Ｍを長くしなくとも、設定の共振周波数を得ることができる。これにより、各主面部２Ｍ，３Ｍの小型化（つまり、給電放射電極２と無給電放射電極３の小型化）を図ることができる。
【００３７】
さらに、この第１実施形態例では、給電放射電極２と無給電放射電極３の各接地用電極部位２Ｇ，３Ｇが特有な形態となっているので、この構成も、各主面部２Ｍ，３Ｍの小型化に寄与している。すなわち、一般的には、図３（ｂ）に示されるように、給電放射電極２の接地用電極部位２Ｇは給電放射電極２側の領域内に形成され、無給電放射電極３の接地用電極部位３Ｇは無給電放射電極３側の領域内に形成されている。これに対して、この第１実施形態例では、図３（ａ）に示されるように、給電放射電極２の接地用電極部位２Ｇは、給電放射電極２側から無給電放射電極３側の領域に伸長形成され、また、無給電放射電極３の接地用電極部位３Ｇは、無給電放射電極３側から給電放射電極２側の領域に伸長形成されている。つまり、一般的には、接地用電極部位２Ｇ，３Ｇは自身の領域から食み出ることなく自身の領域内に収まっていたが、この第１実施形態例では、接地用電極部位２Ｇ，３Ｇは自身の領域から隣の領域に入り込んでいる。このため、第１実施形態例において特有な構成を持つ接地用電極部位２Ｇ，３Ｇは、その物理的な長さを長くすることが容易にできる。すなわち、この第１実施形態例に示す接地用電極部位２Ｇ，３Ｇは、同構造を取ることで、同じアンテナ体積でも物理的な長さを長くすることができるので、給電放射電極２と無給電放射電極３のそれぞれの電気長を長くすることができて、アンテナのＱを上げることなく（言い換えれば、広帯域なままで）給電放射電極２と無給電放射電極３の小型化を促進させることができる。
【００３８】
ところで、給電放射電極２と無給電放射電極３の各々の基本周波数は、それぞれ、給電放射電極２、無給電放射電極３の電気長によって定まり、給電放射電極２と無給電放射電極３の各々の高次周波数は、それぞれ、基本周波数のほぼ整数倍となる。このため、基本周波数を調整しようとすると、基本周波数だけでなく、高次周波数をも変動してしまうので、基本周波数および高次周波数を両方共に設定の周波数に調整することが難しい。
【００３９】
この第１実施形態例では、そのような周波数調整の難しさを軽減するために、給電放射電極２と無給電放射電極３のうちの一方又は両方（図１の例では無給電放射電極３）にはスリット１０が形成されている。つまり、スリット１０の形成位置や、形状や、長さや、幅などを可変することによって、給電放射電極２や無給電放射電極３の電気長が可変する。このため、スリット１０を利用することで、給電放射電極２や無給電放射電極３の基本周波数の調整を行うことができるのはもちろんであるが、スリット１０の形状を最適化すれば、基本周波数が変動する可変幅に比べて高次周波数の可変幅の方が大きくできるので、高次周波数の調整が容易となる。つまり、スリット１０を利用することで、基本周波数の変動を抑制しながら高次周波数の調整を行うことができるので、高次周波数の調整が容易となる。すなわち、スリット１０は、給電放射電極２あるいは無給電放射電極３の共振周波数（特に、高次周波数）の調整機能を持つものである。
【００４０】
なお、スリット１０により高次周波数の調整が容易となる要因の一つは、スリット１０に生じる容量Ｃｓが関与している。この第１実施形態例では、そのスリット１０の容量Ｃｓを調整するために、スリット１０には誘電体８が介設されている。
【００４１】
この第１実施形態例では、給電放射電極２と無給電放射電極３の各主面部２Ｍ，３Ｍにおいて、ショート接続側となる端縁Ｅｇｓに対向する端縁部分２ｏｅ，３ｏｅが開放端となっている。これら開放端２ｏｅ，３ｏｅと基板面４ａとの間の間隙には誘電体８（８ａ）が介設されている。開放端２ｏｅ，３ｏｅと基板面４ａとの間が空隙である場合に比べて、誘電体８ａを介設することによって、開放端２ｏｅ，３ｏｅと基板面４ａ間に生じる容量Ｃｇが大きくなる。この開放端２ｏｅ，３ｏｅと基板面４ａ間の容量Ｃｇは、給電放射電極２と無給電放射電極３の各共振周波数（つまり、給電放射電極２と無給電放射電極３の電気長）に大きく関与する。
【００４２】
この第１実施形態例では、給電放射電極２および無給電放射電極３の小型化を考慮しながら、給電放射電極２と無給電放射電極３にそれぞれ設定の基本周波数および高次周波数を持たせることができるように、実験やシミュレーション等によって、給電放射電極２と無給電放射電極３の各主面部２Ｍ，３Ｍの広さや形状や、各接地用電極部位２Ｇ，３Ｇの長さや、誘電体８の誘電率や、スリット１０の形状や形成位置や幅などが設定されている。
【００４３】
この第１実施形態例の複共振アンテナ構造１は上記のように構成されている。本発明者は第１実施形態例の複共振アンテナ構造１の構成から得られる効果を実験により確認している。その実験では、図５（ａ）に示されるような複共振アンテナ構造１と、図５（ｂ）に示されるような複共振アンテナ構造１５とを用意した。それら複共振アンテナ構造１，１５は、接地用電極部位２Ｇ，３Ｇに関わる構成以外の構成はほぼ同様である。つまり、図５（ａ）の複共振アンテナ構造１では、この第１実施形態例に示したように、接地用電極部位２Ｇ，３Ｇは電極面の一部を間隔を介し対向させながら自身の領域から隣の領域に伸長形成した形態を有している。これに対して、図５（ｂ）の複共振アンテナ構造１５では、接地用電極部位２Ｇ，３Ｇは電極面が対向せずに横並びしている。
【００４４】
複共振アンテナ構造１，１５において、当該複共振アンテナ構造１，１５の幅ｗは４０ｍｍであり、複共振アンテナ構造１，１５の長さｌは２０ｍｍであり、基板４に対する給電放射電極２と無給電放射電極３の各主面部２Ｍ，３Ｍの高さ位置ｈは４ｍｍである。また、給電放射電極２と無給電放射電極３が配設される基板４の幅Ｄは４０ｍｍであり、長さＬは８０ｍｍであり、厚みは１ｍｍである。さらに、基本モードおよび高次モードの周波数帯が複共振アンテナ構造１と複共振アンテナ構造１５とでほぼ同じとなるように、複共振アンテナ構造１，１５のそれぞれの給電放射電極２と無給電放射電極３の電気長が調整されている。
【００４５】
また、この実験では、図５（ａ）の構成を持つ複共振アンテナ構造１において、接地用電極部位２Ｇ，３Ｇ間の間隔ｄが異なる複数種の複共振アンテナ構造１を用意した。ここでは、その間隔ｄが１ｍｍのものと、１．８ｍｍのものと、２．５ｍｍのものとの３種を用意した。つまり、この実験では、図５（ｂ）の構成を持つ複共振アンテナ構造１５（サンプルＡとする）と、図５（ａ）の構成を持ち前記間隔ｄが１ｍｍの複共振アンテナ構造１（サンプルＢとする）と、間隔ｄが１．８ｍｍの複共振アンテナ構造１（サンプルＣとする）と、間隔ｄが２．５ｍｍの複共振アンテナ構造１（サンプルＤとする）との４種の複共振アンテナ構造を用意した。なお、サンプルＢ〜Ｄにおいて、接地用電極部位２Ｇ，３Ｇ間の間隔には、誘電体７（比誘電率εｒ＝６．７）を介設した。
【００４６】
それらサンプルＡ〜Ｄのそれぞれについて、アンテナ効率を調べた結果が図６（ａ）のグラフおよび表１に示され、パターン平均化利得を調べた結果が図６（ｂ）のグラフおよび表２に示され、リターンロスを調べた結果が図６（ｃ）のグラフに示されている。なお、パターン平均化利得とは、図７に示すように地面に垂直な回転軸Ｏを中心として、給電放射電極２と無給電放射電極３が外側を向く姿勢に配置した複共振アンテナ構造１，１５を回転させながら、水平偏波に関する利得と、垂直偏波に関する利得とをそれぞれ予め定めた回転角度で測定し、その測定結果を平均化したものである。この実験では、パターン平均化利得は、水平偏波の平均利得から９ｄＢを差し引いた値を垂直偏波の平均利得に加算して平均化計算を行い得られたものである。また、図６（ａ）、（ｂ）に示す実線ＦＬは図６（ｃ）の８００ＭＨｚに位置する共振（ｆＬ）に関するものであり、実線ＦＨは図６（ｃ）の９５０ＭＨｚに位置する共振（ｆＨ）に関するものである。
【００４７】
【表１】

Figure 2004297268
【００４８】
【表２】
Figure 2004297268
【００４９】
図６（ｃ）のグラフに示されるように、サンプルＡ〜Ｄは、ほぼ同じ共振周波数に調整されている。また、図６（ａ）のグラフに示されるように、この第１実施形態例の特有な構成を備えたサンプルＢ，Ｃは、第１実施形態例の特有な構成を持たないサンプルＡに比べると、アンテナ効率の向上を見ることができる。また、図６（ｂ）に示されるように、第１実施形態例の特有な構成を持つサンプルＢ，Ｃ，Ｄは第１実施形態例の特有な構成を持たないサンプルＡよりもパターン平均化利得が向上している。
【００５０】
なお、サンプルＤはこの第１実施形態例の特有な構成を備えているが、当該サンプルＤのアンテナ効率はサンプルＡ〜Ｃに比べて悪くなっている。これは、接地用電極部位２Ｇ，３Ｇ間の間隔ｄをサンプルＢ，Ｃのものよりも広げたために、接地用電極部位２Ｇのショート接続側となる端縁Ｅｇｓが、サンプルＡ〜Ｃのものよりも基板４の内側となり、これにより、前記した理由によって主面部２Ｍの面積が狭くなったためであると考えられる。
【００５１】
この本発明者による実験の結果にも示されているように、この第１実施形態例の特有な構成を備えることによって、アンテナ効率の向上およびパターン平均化利得を向上させることができる。その理由は、前記したように良好な複共振状態を得ることができることの他に、次に示すようなことが考えられる。つまり、この第１実施形態例では、給電放射電極２と無給電放射電極３の各接地用電極部位２Ｇ，３Ｇは、それぞれ、自身の領域から隣の領域に伸長形成される形態を有し、各接地用電極部位２Ｇ，３Ｇの長さを長くできる構成となっている。このため、接地用電極部位２Ｇ，３Ｇの幅を狭くすることなく、各接地用電極部位２Ｇ，３Ｇの物理的な長さを長くすることで、アンテナの占有スペースを変化せずに、給電放射電極２と無給電放射電極３の電気長を長くできる。換言すれば、接地用電極部位２Ｇ，３Ｇの電極幅の狭小化に起因した電力損失増加を抑制しながら、給電放射電極２と無給電放射電極３の電気長を長くできる。この電力損失抑制の効果によってアンテナ効率が向上したと考えられる。
【００５２】
また、給電放射電極２と無給電放射電極３の波長短縮効果を目的に主面部２Ｍ，３Ｍの基板側に誘電体８が設けられるが、その誘電体８の形成量が多くなって主面部２Ｍ，３Ｍと基板面４ａとの間の誘電率が高くなると、帯域幅が狭くなるという問題が発生する。これに対して、この第１実施形態例では、接地用電極部位２Ｇ，３Ｇの物理的な長さを長くすることで給電放射電極２と無給電放射電極３の電気長を長くすることができるので、誘電体８の形成量を抑えることができる。これにより、広帯域化を図ることができ、このこともアンテナ効率向上に寄与していると考えられる。
【００５３】
さらにまた、この第１実施形態例では、接地用電極部位２Ｇ，３Ｇは、それぞれ、基板４の短辺側の端縁部に接続されている上に、自身の領域から隣の領域に伸長形成されている。このため、給電放射電極２や無給電放射電極３に流れる電流に基づいて基板４に励起される電流は、図８の実線Ｉに示されるように、給電放射電極２と無給電放射電極３の主面部２Ｍ，３Ｍの並設方向（基板短辺に沿う方向）に沿うように流れた後に基板長辺に沿って流れるというような経路でもって通電することとなる。これに対して、図３（ｂ）に示されるように接地用電極部位２Ｇ，３Ｇが自身の領域から出ない場合には、基板４に誘起される電流は、図８の点線ｉに示されるような基板長辺に沿う真っ直ぐな経路で通電する。このような基板４の誘起電流の経路の違いによって、この第１実施形態例の構成では、その誘起電流の経路長を長くできる結果、誘起電流による基板４のアンテナとしての機能を高めることができる。このことは、広帯域化と、アンテナ効率向上と、複共振アンテナ構造１が携帯型電話機に内蔵される場合には通話時に地面に対して垂直な偏波を重視するパターン平均化利得の向上に関与している。
【００５４】
以下に、第２実施形態例を説明する。なお、この第２実施形態例の説明において第１実施形態例と同一構成部分には同一符号を付し、その共通部分の重複説明は省略する。
【００５５】
この第２実施形態例の複共振アンテナ構造１が図９（ａ）の模式的な斜視図に示されている。また、図９（ｂ）には図９（ａ）の右側から複共振アンテナ構造１を見た側面図が模式的に示されている。さらに、図９（ｃ）には給電放射電極２と無給電放射電極３が抜き出され展開図により示されている。
【００５６】
この第２実施形態例では、基板４の短辺側の端面から基板長辺に沿う方向に突出したグランド接続用板状部材２０が設けられている。複共振アンテナ構造１の給電放射電極２と無給電放射電極３の各接地用電極部位２Ｇ，３Ｇは、それぞれ、基板４の端縁部分に接続するのに代えて、そのグランド接続用板状部材２０の突出先端部に接続されている。この第２実施形態例では、給電放射電極２および無給電放射電極３と、グランド接続用板状部材２０との接続体は、ループ状に形成されている。つまり、その接続体は、グランド接続用板状部材２０の端部が基板４の端面に接続され当該接続部分を起点として基板４から離れる方向に膨らみながら基板４の端面を囲むループ状の経路でもって基板４の表面側に回り込み当該基板４の表面と間隔を介して配置されている。
【００５７】
この第２実施形態例においても、第１実施形態例と同様に、給電放射電極２の接地用電極部位２Ｇは、給電放射電極２側から無給電放射電極３側に伸び当該伸長先端部が無給電放射電極３側のグランド接続用板状部材２０部分に接続されている。また、無給電放射電極３の接地用電極部位３Ｇは、給電放射電極２の接地用電極部位２Ｇよりも基板４側に配置され、当該接地用電極部位３Ｇは、無給電放射電極３側から給電放射電極２側に伸び当該伸長先端部が給電放射電極２側のグランド接続用板状部材２０部分に接続されており、給電放射電極２と無給電放射電極３の接地用電極部位２Ｇ，３Ｇは、互いに電極面の一部を対向させて配置されている。それら接地用電極部位２Ｇ，３Ｇ間には誘電体７が介設されている。
【００５８】
この第２実施形態例では、基板４は通信機の回路基板として機能するものであり、複共振アンテナ構造１は、その基板４の端部に配置され、基板４と共に通信機の筐体内に収容配置される。通信機の筐体にはデザインのために端部分に絞る方向のテーパが付けられている場合がある。この第２実施形態例では、その通信機の筐体の形状を考慮している。つまり、給電放射電極２と無給電放射電極３の各主面部２Ｍ，３Ｍにおいて、基板４から食み出している部分Ｂ（図９（ｂ）参照）には、グランド接続用板状部材２０の突出先端部側（接地用電極部位形成側）に向かうに従ってグランド接続用板状部材２０との間の間隔が狭くなる傾きが付けられている。この主面部２Ｍ，３Ｍの傾きは、通信機の筐体の端部のテーパに合わせたものであり、この第２実施形態例の複共振アンテナ構造１は、通信機の筐体の端部に嵌め合わせることができて、通信機の筐体端部のデッドスペースを無くすことができる構成となっている。
【００５９】
また、給電放射電極２の主面部２Ｍの開放端２ｏｅは、図９（ａ）に示す基板４の右側の長辺側の端縁領域に配置されている。また、無給電放射電極３の主面部３Ｍの開放端３ｏｅは、図９（ａ）に示す基板４の左側の長辺側の端縁領域に配置されている。
【００６０】
つまり、この第２実施形態例では、アンテナ形成領域として許容された領域の中で、接地用電極部位２Ｇ，３Ｇとグランド接続用板状部材２０の接続部分Ｐ２ｇ，Ｐ３ｇから最も離れた部分に、給電放射電極２と無給電放射電極３の各開放端２ｏｅ，３ｏｅが配設されている。これにより、予め規制されたアンテナ形成領域の中で、接地用電極部位２Ｇ，３Ｇがグランド接続用板状部材２０に接続している部分Ｐ２ｇ，Ｐ３ｇから、開放端２ｏｅ，３ｏｅに至るまでの経路の長さをより長くすることができる。このため、給電放射電極２と無給電放射電極３の電気長を長くすることができる。これにより、広帯域化を維持したままで給電放射電極２と無給電放射電極３の小型化を図ることができる。
【００６１】
また、この第２実施形態例では、給電放射電極２と無給電放射電極３の各開放端２ｏｅ，３ｏｅが形成されている部分、つまり、基板４の長辺側の端縁領域に配置されている部分は、基板４の長辺側の端縁に向かうに従って基板４との間の間隔が狭くなる傾きが付けられている。この傾きも、前記同様に、通信機の筐体の端部のテーパに合わせたものである。
【００６２】
さらに、この第２実施形態例では、グランド接続用板状部材２０の少なくとも中央領域には穴部２１が形成されており、この穴部２１の形成部分には通信機の部品を配置することができる構成となっている。例えば、この第２実施形態例の複共振アンテナ構造１を携帯型電話機に内蔵する場合には、複共振アンテナ構造１の基板４は携帯型電話機の回路基板と成し、給電放射電極２および無給電放射電極３は、通話中に天頂側となる回路基板のトップ側端部に配設される。携帯型電話機のトップ側にはスピーカーが設けられており、複共振アンテナ構造１のグランド接続用板状部材２０に形成した穴部２１の内部には、例えばそのスピーカーの部品を配設する。
【００６３】
この第２実施形態例では、給電放射電極２および無給電放射電極３は、接地用電極部位２Ｇ，３Ｇが第１実施形態例に示した特有な構成を備えている上に、給電放射電極２および無給電放射電極３は、グランド接続用板状部材２０の突出先端部に接続され、当該給電放射電極２および無給電放射電極３と、グランド接続用板状部材２０との接続体は、基板４の表面と裏面のうちの一方側から他方側に回り込むループ状の形態を有しているので、給電放射電極２および無給電放射電極３の物理的体積を大きくすることができたり、電極面が拡大して、アンテナ効率等のアンテナ特性を大幅に改善することができる。
【００６４】
以下に、第３実施形態例を説明する。この第３実施形態例は通信機に関するものである。この第３実施形態例の通信機において特徴的なことはアンテナとして、第１と第２の各実施形態例に示した複共振アンテナ構造１のうちの何れか一方が設けられていることである。アンテナ構成以外の通信機構成には様々な構成があり、ここでは、アンテナ以外の構成は何れの構成を採用してもよい。また、この第３実施形態例の通信機に設けられる複共振アンテナ構造１の説明は第１又は第２の実施形態例で述べたので、その説明は省略する。
【００６５】
なお、この発明は第１〜第３の各実施形態例に限定されるものではなく、様々な実施の形態を採り得る。例えば、第１実施形態例では、給電放射電極２と無給電放射電極３のうちの一方側の無給電放射電極３に共振周波数調整用のスリット１０が設けられ、また、第２実施形態例では、他方側の給電放射電極２に共振周波数調整用のスリット１０が設けられていたが、例えば図１０に示されるように、給電放射電極２と無給電放射電極３の両方に共振周波数調整用のスリット１０を形成してもよい。
【００６６】
さらに、第２実施形態例では、グランド接続用板状部材２０は、基板４の端面に接続されているものであったが、例えば、図１０に示されるような、基板４とは別個独立のグランド接続用板状部材２０を基板４の端面よりも突出させて配置し、そのグランド接続用板状部材２０の突出先端部に給電放射電極２と無給電放射電極３の各接地用電極部位２Ｇ，３Ｇをそれぞれ接続させてもよい。
【００６７】
なお、図１０に示す複共振アンテナ構造１は、携帯型電話機に内蔵されており、当該複共振アンテナ構造１は、通話中に天頂側となる携帯型電話機の回路基板のトップ側端部に配設されている。また、給電放射電極２と無給電放射電極３の各主面部２Ｍ，３Ｍは、それぞれ、端縁部の一部が基板４の長辺側の端縁領域に配置されており、その基板長辺側の端縁領域に配置されている端縁部分には、基板長辺側の端縁に向かうに従って基板面との間隔が狭くなる傾きが付けられている。つまり、基板４が収容される筐体の形状に合わせた傾きが付けられている。
【００６８】
さらに、第２実施形態例では、給電放射電極２および無給電放射電極３と、グランド接続用板状部材２０との接続体が基板４の端縁を囲むループ状に形成されていたが、例えば、図１１に示されるように、給電放射電極２および無給電放射電極３だけをグランド接続用板状部材２０の端縁（基板４の端縁）を囲むループ状に形成してもよい。また、グランド接続用板状部材２０を省略した構成とし、図１１に示すようなループ状の給電放射電極２および無給電放射電極３を直接的に基板４の端部に接続する構成としてもよい。
【００６９】
さらに、第１〜第３の各実施形態例では、給電放射電極２と無給電放射電極３の各接地用電極部位２Ｇ，３Ｇは、それぞれ、基板面４ａ（グランド接続用板状部材２０）に対して直交方向に起立していたが、例えば、図１２に示されるように、接地用電極部位２Ｇ，３Ｇは、基板面４ａ（グランド接続用板状部材２０）に対して傾いていてもよい。
【００７０】
さらに、第１〜第３の各実施形態例では、給電放射電極２と無給電放射電極３は、基板４の端部に配置され、各接地用電極部位２Ｇ，３Ｇは基板４の端縁部に接続されていたが、例えば、給電放射電極２および無給電放射電極３を基板４の端部以外の部分に設けても、給電放射電極２や無給電放射電極３の通電電流に起因して基板４に誘起される電流の経路長を満足できる程に長くできる場合には、給電放射電極２および無給電放射電極３を基板４の端部以外の部分に設けてもよい。
【００７１】
さらに、基板４は長方形状であったが、長方形状以外の形状の基板４を用いてもよいものである。
【００７２】
【発明の効果】
この発明によれば、給電放射電極の主面部と、無給電放射電極の主面部とは水平方向に間隔を介して隣接並設され、それら各主面部のショート接続側となる端縁部分から、それぞれ、伸設して基板に接続する接地用電極部位が設けられている。その給電放射電極の接地用電極部位は当該給電放射電極側から無給電放射電極側に伸び当該伸長先端部が無給電放射電極側の基板部分に接続されている。また、無給電放射電極の接地用電極部位は当該無給電放射電極側から給電放射電極側に伸び当該伸長先端部が給電放射電極側の基板部分に接続されており、給電放射電極と無給電放射電極の各接地用電極部位は互いに電極面の一部を間隔を介し対向させて配置されている。
【００７３】
給電放射電極の接地用電極部位と、無給電放射電極の接地用電極部位との間に生じる容量は、給電放射電極と無給電放射電極間の電磁結合量に関与するものである。この発明では、給電放射電極と無給電放射電極の各接地用電極部位の電極面の一部が互いに間隔を介して対向するように構成した。このため、従来のように給電放射電極と無給電放射電極の各接地用電極部位の電極面が対向せずに横並びしている場合に比べて、本発明では、給電放射電極の接地用電極部位と、無給電放射電極の接地用電極部位との間の容量を大きくすることができる。これにより、その給電放射電極と無給電放射電極の接地用電極部位間の容量が、給電放射電極と無給電放射電極間の電磁結合量に関与する度合いが大きくなる。このため、その容量の可変調整によって、給電放射電極と無給電放射電極間の電磁結合量を調整することが容易となるし、また、その容量の増加によって容量の可変範囲を広げることができるので、当該容量調整による電磁結合量調整範囲を広げることができる。
【００７４】
つまり、給電放射電極の接地用電極部位と、無給電放射電極の接地用電極部位との間の容量は、給電放射電極と無給電放射電極間の電磁結合量を調整する結合量調整部として機能することができる。
【００７５】
さらに、その容量調整による電磁結合量の調整は、主面部ではなく、接地用電極部位を利用しており、接地用電極部位は、主面部に比べて、設計の自由度が高いものである。このため、給電放射電極と無給電放射電極の接地用電極部位間の容量を利用した給電放射電極と無給電放射電極間の電磁結合量の調整は、主面部を利用して電磁結合量の調整を行う場合に比べて、簡単に行うことができる。
【００７６】
さらにまた、その給電放射電極と無給電放射電極の接地用電極部位間の容量調整による電磁結合量の調整は、定量的に、かつ、精度良く行うことができることが本発明者によって確認されている。
【００７７】
給電放射電極と無給電放射電極の複共振状態は、それら給電放射電極と無給電放射電極間の電磁結合の状態によって定まる。この発明では、上述したように、給電放射電極と無給電放射電極間の電磁結合量を簡単かつ高精度に制御することができるので、アンテナ特性が良好となる給電放射電極と無給電放射電極の適切な複共振状態を簡単に得ることができる。すなわち、アンテナ特性に優れた複共振アンテナ構造およびそれを備えた通信機を提供することができる。
【００７８】
また、この発明では、接地用電極部位は、従来のように主面部と基板を最短距離で接続する形態ではなく、給電放射電極側から無給電放射電極側に、あるいは、無給電放射電極側から給電放射電極側に伸長し当該伸長先端部が基板に接続する形態となっている。このため、この発明の構成を備えることによって、接地用電極部位の長さを長くできる。
【００７９】
この接地用電極部位の延長化により、給電放射電極と無給電放射電極の各電気長を長くすることができる。これにより、従来のように最短距離で基板と主面部を接続する接地用電極部位が設けられているものと、接地用電極部位の延長が図られている本発明の構成を備えたものとで、同等の帯域幅、アンテナ効率を満足させようとする場合に、本発明の構成を備えることによって、主面部の面積を小さくすることができる。つまり、複共振アンテナ構造の小型化を図ることができ、また、その複共振アンテナ構造の小型化に伴って、本発明の複共振アンテナ構造を備えた通信機の小型化を図ることができる。
【００８０】
さらに、接地用電極部位の延長化により、給電放射電極と無給電放射電極のそれぞれの電気長を長くすることができるために、次に示すような効果を得ることもできる。例えば、給電放射電極と無給電放射電極の小型化を図る手法の一つとして、主面部と基板との間に誘電体を形成して当該主面部と基板間の誘電率を高めることがある。この発明では、接地用電極部位の延長化により、アンテナ体積を変化させずに、給電放射電極と無給電放射電極の電気長を長くすることができるので、主面部と基板との間の誘電体の形成量を減少させることができる。このため、その誘電体に起因した周波数帯域の狭小化を防止して通信用の周波数帯の広帯域化を図ることができる。また、材料コストの低減を図ることができる。
【００８１】
さらに、この発明では、接地用電極部位は、給電放射電極側から無給電放射電極側に、あるいは、無給電放射電極側から給電放射電極側に伸長し当該伸長先端部が基板に接続する形態となっている。このため、給電放射電極や無給電放射電極の通電電流に基づいて基板に誘起される電流は、給電放射電極と無給電放射電極の主面部の並設方向と同様な方向又は並設方向に近い向きでもって基板に流れた後に向きを変えて、給電放射電極又は無給電放射電極の主面部における接地用電極部位形成側から開放端側に向かう方向に誘起電流が基板を流れる。このような誘起電流の経路によって当該誘起電流の経路長を長くすることができる結果、誘起電流による基板のアンテナ機能を高めることができる。これにより、周波数帯の広帯域化や、アンテナ効率の向上およびパターン平均化利得の向上を図ることができる。
【００８２】
さらに、この発明では、給電放射電極と無給電放射電極の各主面部は水平方向に隣接並設させる構成である。このため、給電放射電極と無給電放射電極の両方の主面部を、例えば仕様などによって定められている高さ制限の中で最も高い位置に配置することができる。これにより、給電放射電極の主面部と無給電放射電極の主面部との両方に関して基板（つまりグランド）から受ける悪影響を軽減することができる。つまり、主面部が基板に近い場合には、グランドの悪影響を受けてアンテナ利得が低下し易いが、この発明の構成を備えることによって、給電放射電極の主面部および無給電放射電極の主面部を両方共に基板から離すことができるので、グランドからの悪影響が軽減されて、アンテナ利得を向上させることができる。
【００８３】
給電放射電極の接地用電極部位と、無給電放射電極の接地用電極部位との間の間隙に誘電体を介設したものにあっては、給電放射電極と無給電放射電極の接地用電極部位間が空隙である場合に比べて、給電放射電極と無給電放射電極の接地用電極部位間の容量を大幅に増加することが容易にできる。つまり、給電放射電極と無給電放射電極の接地用電極部位間の容量調整可能な範囲を広げることができて、給電放射電極と無給電放射電極の電磁結合量の調整がより容易となる。
【００８４】
また、給電放射電極と無給電放射電極のうちの一方又は両方の接地用電極部位に非電極部が形成されているものにあっては、給電放射電極と無給電放射電極の接地用電極部位間の間隔を広げることなく、給電放射電極と無給電放射電極の接地用電極部位間の容量を減少させることができる。つまり、給電放射電極と無給電放射電極の接地用電極部位間の間隔を広げようとすると、例えば仕様などによるアンテナ形成領域の規制などに起因して給電放射電極と無給電放射電極のうちの一方側の主面部の面積を減少させなければならない事態が発生することがある。このような場合には、主面部の面積減少によってアンテナ利得が低下する等の問題が発生する虞がある。これに対して、この発明では、給電放射電極と無給電放射電極のうちの一方又は両方の接地用電極部位に非電極部を形成することで、給電放射電極と無給電放射電極の接地用電極部位間の間隔を広げることなく、給電放射電極と無給電放射電極間の電磁結合量の調整を行うことができる。このため、上記したような主面部の面積減少によるアンテナ利得低下の問題を回避することができる。
【００８５】
給電放射電極と無給電放射電極のそれぞれにおいて、接地用電極部位が基板に接続している部分から電気的に最も離れた主面部の端縁部分が開放端となっているものにあっては、給電放射電極と無給電放射電極のそれぞれの電気長をより長くすることができる。これにより、前記したようなアンテナ効率向上などのアンテナ特性のより一層の向上を図ることができる。
【００８６】
また、給電放射電極と無給電放射電極の一方又は両方の開放端において、開放端と基板間の間隙に誘電体が介設されているものにあっては、開放端と基板間の容量を増加することができる。これによっても、波長短縮効果により給電放射電極あるいは無給電放射電極の小型化ができる。
【００８７】
給電放射電極と無給電放射電極のうちの一方又は両方にスリットが形成されているものにあっては、高次側の共振周波数の調整が容易となる。このため、マルチバンド化に対応することが容易にできる。さらに、スリットに誘電体を形成したものにあっては、スリットを利用した放射電極の共振周波数の調整がより容易となり、よりマルチバンド化が容易となる。
【００８８】
さらに、給電放射電極と無給電放射電極の各接地用電極部位が基板の端縁部分に接続されているものや、長方形状の基板の短辺側の端縁部分に接続されているものにあっては、給電放射電極や無給電放射電極に流れる電流に起因して基板に誘起される電流によって、基板もアンテナの一部として機能させることが容易となる。
【００８９】
さらに、給電放射電極や無給電放射電極の主面部に傾きが付けられているものにあっては、例えば通信機の筐体のテーパ形状に合わせた傾きを給電放射電極や無給電放射電極の主面部に持たせることによって、給電放射電極や無給電放射電極を筐体のテーパ部分の内壁面に添わせて配置できる。これにより、筐体のテーパ形状に起因したデッドスペースを無くすことができる。
【００９０】
さらに、給電放射電極と無給電放射電極が、あるいは、給電放射電極および無給電放射電極と、グランド接続用板状部材２０との接続体が、基板の表面と裏面の一方側から基板端縁を囲むループ状の経路を通って他方側の基板面側に回り込むループ形状と成している場合には、給電放射電極と無給電放射電極の電気長をより長くすることが容易となって、アンテナ特性をより一層向上させることができる。
【００９１】
この発明の複共振アンテナ構造を備えた通信機にあっては、上述したような優れた効果を持つ複共振アンテナ構造が設けられているので、通信の信頼性が高く、しかも、小型な通信機を提供することができる。
【図面の簡単な説明】
【図１】第１実施形態例の複共振アンテナ構造を説明するための図である。
【図２】図１に示す複共振アンテナ構造を図１に示すａ方向から見た図である。
【図３】第１実施形態例に示す給電放射電極と無給電放射電極の接地用電極部位を説明するための図である。
【図４】給電放射電極と無給電放射電極の接地用電極部位のその他の形態例を説明するための図である。
【図５】本発明者が行った実験に使用した複共振アンテナ構造を示すモデル図である。
【図６】本発明者が行った実験の結果を示すグラフである。
【図７】パターン平均化利得を説明するための図である。
【図８】給電放射電極や無給電放射電極の通電電流に起因して基板に誘起される電流の経路の一例を説明するための図である。
【図９】第２実施形態例の複共振アンテナ構造を説明するための図である。
【図１０】その他の実施形態例を説明するための図である。
【図１１】ループ形状の給電放射電極と無給電放射電極のその他の形態例を示す側面図である。
【図１２】給電放射電極と無給電放射電極の接地用電極部位のその他の形態例を説明するための図である。
【図１３】特許文献１に記載のアンテナ構造の一つを説明するための図である。
【図１４】特許文献２に記載のアンテナ構造の一つを説明するための図である。
【符号の説明】
１ 複共振アンテナ構造
２ 給電放射電極
３ 無給電放射電極
２Ｍ，３Ｍ 主面部
２Ｇ，３Ｇ 接地用電極部位
４ 基板
７，８ 誘電体
１０ スリット
１１ 孔部
１２ 切り欠き
２０ グランド接続用板状部材[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multiple resonance antenna structure for performing wireless communication and a communication device including the same.
[0002]
[Background Art]
FIG. 13 shows an example of a multiple resonance antenna structure (see Patent Document 1). In the multiple resonance antenna structure 40, two radiation electrodes 41 and 42 are arranged side by side with an interval therebetween. Each of the radiation electrodes 41 and 42 has an L-shape. The radiation electrode 41 has a main surface portion 41 a disposed at an interval from the substrate 43 and a connection for connecting the main surface portion 41 a to the substrate 43. The radiation electrode 42 is also configured to have a main surface portion 42a and a connection portion 42b. A dielectric (Teflon (registered trademark)) 44 is provided between the main surface portions 41 a and 42 a and the substrate 43.
[0003]
Since the substrate 43 is regarded as ground, the connection portions 41b and 42b of the radiation electrodes 41 and 42 function as short-circuit portions for grounding the main surface portions 41a and 42a to ground. In addition, the connection portion 41b of the radiation electrode 41 is connected to, for example, a high-frequency circuit 46 for communication of a communication device via a power supply line 45, and the radiation electrode 41 functions as a power supply radiation electrode. Further, the radiation electrode 42 functions as a parasitic radiation electrode that is not connected to the high-frequency circuit 46. The parasitic radiation electrode 42 is formed so as to electromagnetically couple with the feed radiation electrode 41 to create a multiple resonance state.
[0004]
For example, when a signal for communication is supplied from the high-frequency circuit 46 to the feed radiation electrode 41, the feed radiation electrode 41 is excited based on the signal for communication, thereby performing signal communication (that is, power supply). The radiation electrode 41 performs an antenna operation). In addition, the parasitic radiation electrode 42 is excited by the electromagnetic coupling with the feed radiation electrode 41 along with the excitation of the feed radiation electrode 41, and performs an antenna operation while creating a multiple resonance state with the feed radiation electrode 41. Due to this multiple resonance state, it is possible to broaden the communication frequency band, and it is possible to perform communication in a plurality of frequency bands.
[0005]
FIG. 14 shows another example of a multiple resonance antenna structure (see Patent Document 2). In the multiple resonance antenna structure 50, a main surface portion 52 a of a feed radiation electrode 52 and a main surface portion 53 a of a non-feed radiation electrode 53 are vertically arranged on a substrate 51 with an interval therebetween. Reference numerals 52b and 53b in FIG. 14 indicate short-circuit portions for grounding the feed radiation electrode 52 and the parasitic radiation electrode 53 to the substrate (ground) 51, respectively. Reference numeral 54 denotes a feed line for connecting the feed radiation electrode 51 to, for example, a high-frequency circuit (not shown) of a communication device.
[0006]
Also in this multiple resonance antenna structure 50, similarly to the multiple resonance antenna structure 40, the feed radiation electrode 52 and the parasitic radiation electrode 53 are electromagnetically coupled, and for example, based on a communication signal supplied from a high frequency circuit. At the same time as the feed radiation electrode 52 is excited to perform the antenna operation, the parasitic radiation electrode 53 is also excited by electromagnetic coupling, and the feed radiation electrode 52 and the parasitic radiation electrode 53 perform the antenna operation while creating a multiple resonance state. .
[0007]
[Patent Document 1]
JP-A-1-231404
[Patent Document 2]
JP-A-6-232625
[0008]
[Problems to be solved by the invention]
In the configuration shown in FIG. 13, the feed radiation electrode 41 and the parasitic radiation electrode 42 are arranged side by side in the direction (horizontal direction) along the substrate surface. That is, since the two radiation electrodes 41 and 42 must be arranged side by side, there is a problem that the area of the substrate on which the radiation electrodes 41 and 42 are arranged needs to be large.
[0009]
If the size of the antenna formation area (that is, the area of the substrate on which the feed radiation electrode 41 and the parasitic radiation electrode 42 can be arranged) is limited due to the specifications of the communication device, etc. Therefore, since the feed radiation electrode 41 and the parasitic radiation electrode 42 must be arranged side by side, the size of the feed radiation electrode 41 and the parasitic radiation electrode 42 becomes small, so that the antenna gain is deteriorated or the bandwidth is reduced. There is a problem that deterioration of antenna characteristics such as narrowing is likely to occur.
[0010]
Further, there is a problem that it is difficult to adjust the amount of electromagnetic coupling between the feed radiation electrode 41 and the parasitic radiation electrode 42. In addition, the amount of electromagnetic coupling between the feed radiation electrode 41 and the parasitic radiation electrode 42 varies from product to product, which causes a problem that antenna characteristics vary between products.
[0011]
In the configuration shown in FIG. 14, when the width of the antenna formation region is restricted, the main surface portions 52a and 53a of the radiation electrodes 52 and 53 can be formed larger than in the configuration shown in FIG. The following problems occur. For example, when the radiation electrode is close to the ground, the antenna characteristics are deteriorated due to the influence of the ground. Therefore, when the height of the arrangement of the radiation electrode is limited, the lower feed radiation electrode 52 is connected to the substrate (ground) 51. , And there is a problem that the antenna characteristics are likely to deteriorate.
[0012]
Also in the configuration shown in FIG. 14, similarly to the configuration in FIG. 13, it is difficult to adjust the amount of electromagnetic coupling between the feeding radiation electrode 52 and the parasitic radiation electrode 53, and it is difficult to adjust the amount of electromagnetic coupling. In addition, the amount of electromagnetic coupling between the feed radiation electrode 52 and the parasitic radiation electrode 53 varies depending on the product, which causes a problem that the antenna characteristics vary between products.
[0013]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to easily adjust a magnetic coupling amount between a feeding radiation electrode and a non-feeding radiation electrode to easily obtain a good double resonance state. Another object of the present invention is to provide a multi-resonant antenna structure having excellent antenna characteristics.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides means for solving the above problems with the following configuration. That is, the present invention relates to a multiple resonance antenna structure in which a feed radiation electrode and a parasitic radiation electrode that create a multiple resonance state are disposed on a substrate equivalent to a ground with an interval therebetween, and Each of the radiation electrodes has a main surface portion disposed at an interval from the substrate surface, and the main surface portion of the feeding radiation electrode and the main surface portion of the non-feeding radiation electrode are adjacent to each other with a horizontal interval therebetween. A grounding electrode portion is provided, which extends from the edge portion on the short connection side of each main surface portion of the feeding radiation electrode and the parasitic radiation electrode, and is connected to the substrate. The ground electrode part extends from the feed radiation electrode side to the parasitic radiation electrode side, and the extended tip is connected to the substrate part on the parasitic radiation electrode side, and the ground electrode part of the parasitic radiation electrode is the parasitic power electrode. On the radiation electrode side On the feeding radiation electrode side, the extension tip portion is extended while being disposed close to the grounding electrode portion of the feeding radiation electrode with an interval connected to the substrate portion on the feeding radiation electrode side. Each of the ground electrode portions is characterized in that a part of a path from a connection portion with the substrate to a connection portion with the main surface portion is additionally provided. Further, a communication device according to the present invention is characterized in that a multi-resonant antenna structure having a characteristic configuration according to the present invention is provided.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
FIG. 1A is a schematic perspective view showing a first embodiment of a multiple resonance antenna structure according to the present invention, and FIG. 1B is a view taken along the line AA in FIG. FIG. The multiple resonance antenna structure 1 is configured such that a feed radiation electrode 2 and a parasitic radiation electrode 3 for creating a multiple resonance state are disposed on a substrate 4 (for example, a circuit board of a communication device) which is regarded as a ground.
[0017]
In the first embodiment, the feed radiation electrode 2 and the parasitic radiation electrode 3 have main surface portions 2M and 3M, respectively, which are arranged at an interval from the surface (substrate surface) 4a of the substrate 4, and the main surface portion. It has grounding electrode portions 2G and 3G connected to the edge portion Egs on the short connection side of 2M and 3M.
[0018]
In the first embodiment, the substrate 4 has a rectangular shape, and the main surface portions 2M and 3M of the feeding radiation electrode 2 and the non-feeding radiation electrode 3 are attached to the ends of the rectangular substrate 4 respectively. The substrates 4 are adjacently arranged side by side in the horizontal direction x along the short side of the substrate 4. In each of the main surface portions 2M and 3M of the feed radiation electrode 2 and the parasitic radiation electrode 3, an edge portion Egs closer to the short side of the substrate is an edge portion on the short connection side. Ground electrode portions 2G and 3G are formed to extend from the edge portion Egs of 3M, respectively.
[0019]
FIG. 2 schematically shows the ground electrode portions 2G and 3G viewed from the direction a in FIG. 1A. As shown in this figure, the grounding electrode portion 3G of the parasitic radiation electrode 3 extends from the parasitic radiation electrode 3 side to the feed radiation electrode 2 side, and the extended end portion of the substrate 4 on the feed radiation electrode 2 side. Is connected to the short side edge portion. Further, the grounding electrode portion 2G of the feeding radiation electrode 2 is disposed closer to the ground electrode portion 3G than the grounding electrode portion 3G of the non-feeding radiation electrode 3 with an interval between the grounding electrode portion 3G. The grounding electrode portion 2G extends from the feeding radiation electrode 2 side to the parasitic radiation electrode 3 side, and its extended tip is connected to the short side edge portion of the substrate 4 on the parasitic radiation electrode 3 side.
[0020]
Each of the grounding electrode portions 2G and 3G of the feed radiation electrode 2 and the parasitic radiation electrode 3 is connected to a connection portion P with the substrate 4. 2g , P 3g From the main surface 2M, 3M 2m , P 3m Some of the routes K2 and K3 leading to are provided. That is, the grounding electrode portions 2G and 3G of the feeding radiation electrode 2 and the parasitic radiation electrode 3 are arranged so that a part of the electrode surface faces each other with an interval therebetween. As a result, a capacitance is generated in the gap between the ground electrode portions 2G and 3G.
[0021]
By the way, in the first embodiment, the ground electrode portion 2G of the feed radiation electrode 2 is connected to the substrate 4 (ground) and also connected to, for example, a communication high-frequency circuit 6 of a communication device (FIG. 1 (a)). )reference). That is, a power supply electrode (not shown) connected to the high-frequency circuit 6 is formed on the surface of the substrate 4, and the ground electrode portion 2 </ b> G of the power supply radiation electrode 2 is directly connected to the power supply electrode on the substrate 4. The feeding radiation electrode 2 is a direct feeding type radiation electrode. The power supply radiation electrode 2 may be a non-contact power supply type (capacitive power supply type) radiation electrode. In this case, the power supply electrode and the power supply site of the power supply radiation electrode 2 are arranged at an interval, and the power supply radiation electrode 2 is connected to the high-frequency circuit 6 via the power supply electrode by electromagnetic coupling with the power supply electrode. You.
[0022]
For example, when a communication signal is supplied from the high-frequency circuit 6 to the ground electrode portion 2G of the feed radiation electrode 2, the signal is transmitted from the ground electrode portion 2G to the main surface portion 2M. Excites to perform antenna operation. Further, in the first embodiment, the parasitic radiation electrode 3 is electromagnetically coupled to the feeding radiation electrode 2, and the parasitic coupling causes the parasitic radiation electrode 3 to be excited by the feeding radiation electrode 2. Excited, whereby the feed radiation electrode 2 and the parasitic radiation electrode 3 create a multiple resonance state. In order for the multiple resonance state of the feed radiation electrode 2 and the parasitic radiation electrode 3 to become an appropriate state in which good antenna characteristics can be obtained, the amount of electromagnetic coupling between the feed radiation electrode 2 and the parasitic radiation electrode 3 must be reduced. Adjustment (control) is important.
[0023]
Generally, the amount of electromagnetic coupling between the feeding radiation electrode 2 and the non-feeding radiation electrode 3 is adjusted by adjusting the interval between the main surface portions 2M and 3M of the feeding radiation electrode 2 and the non-feeding radiation electrode 3. . However, since the main surface portions 2M and 3M are mainly responsible for the radio wave communication operation, in the method of adjusting the amount of electromagnetic coupling, the antenna characteristics are large only by slightly changing the interval between the main surface portions 2M and 3M. Therefore, it is difficult to adjust the amount of electromagnetic coupling with high accuracy so as to improve the antenna characteristics.
[0024]
The present inventor connects the main surface of the feed radiation electrode to the ground (the ground electrode portion 2G in the first embodiment) and connects the main surface of the parasitic radiation electrode to the ground. It is noted that the amount of electromagnetic coupling between the feeding radiation electrode and the parasitic radiation electrode can be adjusted by adjusting the capacitance between the feeding radiation electrode and the parasitic radiation electrode by adjusting the capacitance between the feeding radiation electrode and the non-feeding radiation electrode. That is, in the first embodiment, the capacitance between the grounding electrode portions 2G and 3G of the feeding radiation electrode 2 and the parasitic radiation electrode 3 is determined by the amount of electromagnetic coupling between the feeding radiation electrode 2 and the parasitic radiation electrode 3. It was made to function as a coupling amount adjusting unit for adjustment.
[0025]
For this reason, in the first embodiment, the grounding electrode portions 2G and 3G of the feeding radiation electrode 2 and the parasitic radiation electrode 3 are connected to each other so that the amount of electromagnetic coupling can be easily adjusted. Are arranged to face each other with an interval. As a result, the capacitance between each of the grounding electrode portions 2G and 3G of the feeding radiation electrode 2 and the parasitic radiation electrode 3 is reduced as shown in the model diagram of FIG. Are arranged in the first embodiment as shown in the model diagram of FIG. 3A (i.e., the ground electrode portions 2G and 3G are located on the electrode surfaces). ) Are larger. Since the capacitance between the grounding electrode portions 2G and 3G is increased as described above, the degree of the capacitance between the grounding electrode portions 2G and 3G relating to the electromagnetic coupling amount between the feeding radiation electrode 2 and the parasitic radiation electrode 3 varies. growing. In addition, since the capacitance variable range is expanded by the increase in the capacitance, the variable range of the electromagnetic coupling amount between the feed radiation electrode 2 and the parasitic radiation electrode 3 using the capacitance is also expanded. These facts and the fact that the shape and the like of the main surface portions 2M and 3M do not need to be changed for the adjustment of the amount of electromagnetic coupling allow the use of the capacitance between the grounding electrode portions 2G and 3G to provide the feed radiation electrode 2M. It is easy to adjust the amount of electromagnetic coupling between the antenna and the parasitic radiation electrode 3.
[0026]
Here, when the distance between the ground electrode portions 2G and 3G is d, the dielectric constant between the ground electrode portions 2G and 3G is ε, and the facing area of the ground electrode portions 2G and 3G is S, The capacitance C between the electrode portions for use 2G and 3G can be expressed by the following equation (1).
[0027]
C = ε × (S / d) (1)
[0028]
As can be seen from Equation (1), the capacitance C between the grounding electrode portions 2G and 3G can be increased by increasing the facing area S of the grounding electrode portions 2G and 3G. However, the width and height of the antenna formation area may be limited depending on the specifications and the like. In this case, the size of the grounding electrode portions 2G and 3G is limited. It may not be possible to obtain the required capacitance C (that is, the capacitance corresponding to the amount of electromagnetic coupling at which the multiple resonance state of the feed radiation electrode 2 and the parasitic radiation electrode 3 becomes good) only by adjusting the area S. In consideration of this, in the first embodiment, the dielectric 7 is interposed between the grounding electrode portions 2G and 3G, so that the grounding is made smaller than when the gap is provided between the grounding electrode portions 2G and 3G. The configuration is such that the dielectric constant ε between the electrode portions 2G and 3G is increased to increase the capacitance C between the electrode portions 2G and 3G.
[0029]
Of course, if the capacitance C between the grounding electrode portions 2G and 3G can be made to meet the required capacity without interposing the dielectric 7 between the grounding electrode portions 2G and 3G, It is not necessary to provide the dielectric 7 between the electrode portions 2G and 3G.
[0030]
The adjustment of the capacitance C between the grounding electrode portions 2G and 3G can be performed not only by adjusting the facing area S of the grounding electrode portions 2G and 3G, and by adjusting the dielectric constant ε between the grounding electrode portions 2G and 3G, but also by adjusting the capacitance. It can also be performed by adjusting the distance d between the electrode portions 2G and 3G. However, if the distance d is to be increased, the following problem may occur.
[0031]
The problem arises, for example, when the size of the antenna formation area is restricted by specifications or the like. In other words, the larger the area of each of the main surface portions 2M and 3M of the feed radiation electrode 2 and the parasitic radiation electrode 3 can improve the antenna efficiency, so that the limitation is imposed when the area of the antenna formation region is restricted. The main surface portions 2M and 3M are to be formed as large as possible in the formed antenna formation region. Therefore, for example, the edge position Ek on the open end side of each of the main surface portions 2M and 3M shown in FIG. 1A is inevitably determined. In such a situation, in order to increase the distance d between the grounding electrode portions 2G and 3G, for example, the edge Egs serving as the short connection side of the feeding radiation electrode 2 and the formation position of the grounding electrode portion 2G are set on the substrate. 4, the area of the main surface 2M of the feed radiation electrode 2 becomes smaller. As a result, the antenna efficiency is reduced.
[0032]
For this reason, in consideration of antenna efficiency, it is not preferable to greatly increase the distance d between the grounding electrode portions 2G and 3G. For this reason, the distance d between the grounding electrode portions 2G and 3G may be substantially determined. is there. In this case, for example, it is not possible to reduce the capacitance C between the ground electrode portions 2G and 3G by increasing the distance d. Therefore, for example, one or both of the ground electrode portion 2G of the feed radiation electrode 2 and the ground electrode portion 3G of the parasitic radiation electrode 3 are provided with a non-electrode portion as shown in FIG. A certain hole portion 11 and a notch 12 which is a non-electrode portion as shown in FIG. 4B are formed. Thereby, the facing area S of the ground electrode portions 2G, 3G is reduced. Thus, the capacitance C between the ground electrode portions 2G and 3G can be reduced without increasing the distance d between the ground electrode portions 2G and 3G.
[0033]
Further, a hole or the like is formed in the dielectric 7 disposed between the grounding electrode portions 2G, 3G, and thereby the dielectric constant ε of the dielectric 7 is substantially reduced. , 3G can be reduced without increasing the distance d between the ground electrode portions 2G, 3G. It should be noted that the capacitance C between the grounding electrode portions 2G and 3G can be reduced by combining the formation of the non-electrode portion in the grounding electrode portions 2G and 3G with the formation of a hole or the like in the dielectric 7. It may be.
[0034]
In the first embodiment, the capacitance between the grounding electrode portions 2G and 3G is set so that the multiple resonance state of the feed radiation electrode 2 and the parasitic radiation electrode 3 becomes an appropriate state where good antenna characteristics can be obtained. The adjustment of C (that is, the adjustment of the electromagnetic coupling amount between the feeding radiation electrode 2 and the parasitic radiation electrode 3) is performed by experiments, simulations, or the like, and the opposing area S of the grounding electrode portions 2G and 3G and the grounding electrode portions 2G, 2G, The dielectric constant ε between 3G and the distance d between the ground electrode portions 2G and 3G are set.
[0035]
In the first embodiment, the feeding radiation electrode 2 and the non-feeding radiation electrode 3 create a multiple resonance state in which the antenna characteristics are good as described above, thereby enabling communication in a plurality of frequency bands. I have. That is, the communication operation in the basic mode using the lowest resonance frequency (basic frequency) among the plurality of resonance frequencies of the feed radiation electrode 2 and the parasitic radiation electrode 3 and the resonance frequency higher than the basic frequency (higher frequency). Communication operation in a higher-order mode using the next frequency).
[0036]
Here, the respective impedances of the feed radiation electrode 2 and the parasitic radiation electrode 3 (so that the frequency band of the communication operation in the basic mode and the frequency band of the communication operation in the higher order mode are respectively set frequency bands). The electrical length) is adjusted so that the fundamental frequency and the higher-order frequency of the feed radiation electrode 2 and the parasitic radiation electrode 3 are adjusted. In the first embodiment, the size of each of the main surface portions 2M and 3M of the feed radiation electrode 2 and the parasitic radiation electrode 3 is reduced, and the set fundamental frequency and higher order frequency can be obtained. As shown in (a), a dielectric 8 is provided on the substrate side of each of the main surface portions 2M and 3M. That is, when the dielectric material 8 is provided due to the wavelength shortening effect of the dielectric material 8, a set resonance frequency can be obtained without increasing the length of each of the main surface portions 2M and 3M as compared with the case where the dielectric material 8 is not provided. Can be. This makes it possible to reduce the size of each of the main surface portions 2M and 3M (that is, to reduce the size of the feed radiation electrode 2 and the parasitic radiation electrode 3).
[0037]
Further, in the first embodiment, since the grounding electrode portions 2G and 3G of the feeding radiation electrode 2 and the parasitic radiation electrode 3 have a unique form, this configuration is also different from that of the main surface portions 2M and 3M. This contributes to miniaturization. That is, in general, as shown in FIG. 3B, the grounding electrode portion 2G of the feeding radiation electrode 2 is formed in a region on the feeding radiation electrode 2 side, and the grounding electrode portion of the parasitic radiation electrode 3 is formed. The portion 3G is formed in a region on the parasitic radiation electrode 3 side. On the other hand, in the first embodiment, as shown in FIG. 3A, the grounding electrode portion 2G of the feeding radiation electrode 2 is formed in a region from the feeding radiation electrode 2 side to the parasitic radiation electrode 3 side. The grounding electrode portion 3G of the parasitic radiation electrode 3 extends from the parasitic radiation electrode 3 side to the region of the parasitic radiation electrode 2 side. That is, in general, the grounding electrode portions 2G and 3G are contained in their own region without protruding from their own region. However, in the first embodiment, the grounding electrode portions 2G and 3G are It enters the adjacent area from its own area. For this reason, the physical length of the grounding electrode portions 2G and 3G having a unique configuration in the first embodiment can be easily increased. That is, since the grounding electrode portions 2G and 3G shown in the first embodiment have the same structure, the physical length can be increased even with the same antenna volume. Since the electrical length of each of the radiation electrodes 3 can be increased, it is possible to promote miniaturization of the feed radiation electrode 2 and the parasitic radiation electrode 3 without increasing the Q of the antenna (in other words, while maintaining a wide band). it can.
[0038]
By the way, the fundamental frequencies of the feed radiation electrode 2 and the parasitic radiation electrode 3 are determined by the electrical lengths of the feed radiation electrode 2 and the parasitic radiation electrode 3, respectively. Each higher-order frequency is substantially an integral multiple of the fundamental frequency. For this reason, when trying to adjust the fundamental frequency, not only the fundamental frequency but also the higher-order frequency fluctuates, and it is difficult to adjust both the fundamental frequency and the higher-order frequency to the set frequency.
[0039]
In the first embodiment, one or both of the feeding radiation electrode 2 and the parasitic radiation electrode 3 (parasitic radiation electrode 3 in the example of FIG. 1) are used to reduce such difficulty in frequency adjustment. Is formed with a slit 10. That is, the electrical length of the feed radiation electrode 2 and the parasitic radiation electrode 3 can be varied by changing the formation position, the shape, the length, the width, and the like of the slit 10. For this reason, by utilizing the slit 10, it is of course possible to adjust the fundamental frequency of the feed radiation electrode 2 and the parasitic radiation electrode 3, but if the shape of the slit 10 is optimized, the fundamental frequency can be adjusted. Since the variable width of the higher-order frequency can be made larger than the variable width in which fluctuates, the adjustment of the higher-order frequency becomes easier. In other words, the use of the slit 10 makes it possible to adjust the higher-order frequency while suppressing the fluctuation of the fundamental frequency, thereby facilitating the adjustment of the higher-order frequency. That is, the slit 10 has a function of adjusting the resonance frequency (particularly, a higher-order frequency) of the feed radiation electrode 2 or the parasitic radiation electrode 3.
[0040]
One of the factors that makes it easier to adjust the higher-order frequency by the slit 10 is related to the capacitance Cs generated in the slit 10. In the first embodiment, a dielectric 8 is interposed in the slit 10 in order to adjust the capacitance Cs of the slit 10.
[0041]
In the first embodiment, in each of the main surface portions 2M and 3M of the feeding radiation electrode 2 and the parasitic radiation electrode 3, the edge portions 2oe and 3oe facing the edge Egs on the short connection side are open ends. I have. A dielectric 8 (8a) is provided in a gap between the open ends 2oe, 3oe and the substrate surface 4a. With the interposition of the dielectric 8a, the capacitance Cg generated between the open ends 2oe, 3oe and the substrate surface 4a is larger than in the case where there is a gap between the open ends 2oe, 3oe and the substrate surface 4a. The capacitance Cg between the open ends 2 oe and 3 oe and the substrate surface 4 a greatly affects each resonance frequency of the feed radiation electrode 2 and the parasitic radiation electrode 3 (that is, the electrical length of the feed radiation electrode 2 and the parasitic radiation electrode 3). I do.
[0042]
In the first embodiment, the feed radiation electrode 2 and the parasitic radiation electrode 3 are set to have a set fundamental frequency and a higher order frequency, respectively, while taking the size of the feed radiation electrode 2 and the parasitic radiation electrode 3 into consideration. The width and shape of each main surface 2M, 3M of the feed radiation electrode 2 and the parasitic radiation electrode 3, the length of each ground electrode portion 2G, 3G, The permittivity, the shape, formation position, width, and the like of the slit 10 are set.
[0043]
The multiple resonance antenna structure 1 of the first embodiment is configured as described above. The inventor has confirmed through experiments an effect obtained from the configuration of the multiple resonance antenna structure 1 of the first embodiment. In the experiment, a multiple resonance antenna structure 1 as shown in FIG. 5A and a multiple resonance antenna structure 15 as shown in FIG. 5B were prepared. The configurations of the multiple resonance antenna structures 1 and 15 are substantially the same except for the configuration relating to the ground electrode portions 2G and 3G. That is, in the multiple resonance antenna structure 1 shown in FIG. 5A, as shown in the first embodiment, the grounding electrode portions 2G and 3G have their own regions facing each other with a part of the electrode surface being spaced therebetween. From the first region to the next region. On the other hand, in the multiple resonance antenna structure 15 of FIG. 5B, the ground electrode portions 2G and 3G are arranged side by side without facing the electrode surfaces.
[0044]
In the multiple resonance antenna structures 1 and 15, the width w of the multiple resonance antenna structures 1 and 15 is 40 mm, the length 1 of the multiple resonance antenna structures 1 and 15 is 20 mm, The height position h of each of the main surface portions 2M and 3M of the feed radiation electrode 3 is 4 mm. The width D of the substrate 4 on which the feeding radiation electrode 2 and the parasitic radiation electrode 3 are disposed is 40 mm, the length L is 80 mm, and the thickness is 1 mm. Further, the feed radiation electrode 2 of each of the multiple resonance antenna structures 1 and 15 and the parasitic radiation are set so that the frequency bands of the fundamental mode and the higher-order mode are substantially the same in the multiple resonance antenna structures 1 and 15. The electrical length of the electrode 3 is adjusted.
[0045]
In this experiment, in the multiple resonance antenna structure 1 having the configuration shown in FIG. 5A, a plurality of types of multiple resonance antenna structures 1 having different intervals d between the ground electrode portions 2G and 3G were prepared. Here, three types were prepared, one having a distance d of 1 mm, one having 1.8 mm, and one having 2.5 mm. That is, in this experiment, the multiple resonance antenna structure 15 (sample A) having the configuration of FIG. 5B and the multiple resonance antenna structure 1 (sample A) having the configuration of FIG. B), a multi-resonant antenna structure 1 with a distance d of 1.8 mm (sample C), and a multi-resonant antenna structure 1 with a distance d of 2.5 mm (sample D). A resonant antenna structure was prepared. In samples B to D, a dielectric 7 (relative permittivity εr = 6.7) was interposed between the ground electrode portions 2G and 3G.
[0046]
For each of the samples A to D, the results of examining the antenna efficiency are shown in the graph of FIG. 6A and Table 1, and the results of examining the pattern averaging gain are shown in the graph of FIG. And the result of examining the return loss is shown in the graph of FIG. The pattern averaging gain refers to a multi-resonant antenna structure 1 in which the feeding radiation electrode 2 and the parasitic radiation electrode 3 are arranged to face outward with respect to the rotation axis O perpendicular to the ground as shown in FIG. The gain of the horizontal polarization and the gain of the vertical polarization are measured at predetermined rotation angles while rotating 15, and the measurement results are averaged. In this experiment, the pattern averaging gain was obtained by performing averaging calculation by adding a value obtained by subtracting 9 dB from the horizontal polarization average gain to the vertical polarization average gain. Further, the solid line F shown in FIGS. L Is the resonance (f) located at 800 MHz in FIG. L ) And the solid line F H Is the resonance (f) located at 950 MHz in FIG. H ).
[0047]
[Table 1]
Figure 2004297268
[0048]
[Table 2]
Figure 2004297268
[0049]
As shown in the graph of FIG. 6C, the samples A to D are adjusted to have substantially the same resonance frequency. Further, as shown in the graph of FIG. 6A, the samples B and C having the specific configuration of the first embodiment are compared with the sample A having no specific configuration of the first embodiment. Then, the improvement of the antenna efficiency can be seen. As shown in FIG. 6B, the samples B, C, and D having the specific configuration of the first embodiment are more pattern-averaged than the sample A having no specific configuration of the first embodiment. The gain has improved.
[0050]
Although the sample D has the unique configuration of the first embodiment, the antenna efficiency of the sample D is lower than those of the samples A to C. This is because the distance d between the grounding electrode portions 2G and 3G is wider than that of the samples B and C, so that the edge Egs on the short connection side of the grounding electrode portion 2G is smaller than that of the samples A to C. This is considered to be because the area of the main surface portion 2M was reduced due to the reason described above.
[0051]
As shown in the results of the experiment by the inventor, the provision of the unique configuration of the first embodiment makes it possible to improve the antenna efficiency and the pattern averaging gain. The reason may be as follows, in addition to the fact that a favorable multiple resonance state can be obtained as described above. That is, in the first embodiment, each of the grounding electrode portions 2G and 3G of the feeding radiation electrode 2 and the parasitic radiation electrode 3 has a form extending from its own region to an adjacent region. The length of each of the ground electrode portions 2G and 3G can be increased. Therefore, by increasing the physical length of each of the grounding electrode portions 2G and 3G without reducing the width of the grounding electrode portions 2G and 3G, the feed radiation can be performed without changing the space occupied by the antenna. The electrical length of the electrode 2 and the parasitic radiation electrode 3 can be increased. In other words, the electric length of the feed radiation electrode 2 and the parasitic radiation electrode 3 can be increased while suppressing an increase in power loss due to the narrowing of the electrode width of the ground electrode portions 2G and 3G. It is considered that the effect of suppressing the power loss has improved the antenna efficiency.
[0052]
Further, the dielectric 8 is provided on the substrate side of the main surface portions 2M and 3M for the purpose of shortening the wavelength of the feed radiation electrode 2 and the parasitic radiation electrode 3. However, the amount of the dielectric 8 formed is increased and the main surface portion 2M is formed. , 3M and the substrate surface 4a raise the problem that the bandwidth is narrowed. On the other hand, in the first embodiment, the electrical length of the feeding radiation electrode 2 and the parasitic radiation electrode 3 can be increased by increasing the physical length of the ground electrode portions 2G and 3G. Therefore, the formation amount of the dielectric 8 can be suppressed. As a result, a wider band can be achieved, which is also considered to contribute to an improvement in antenna efficiency.
[0053]
Furthermore, in the first embodiment, the ground electrode portions 2G and 3G are connected to the short side edge of the substrate 4 and extend from their own region to the adjacent region. Have been. For this reason, the current excited in the substrate 4 based on the current flowing through the feed radiation electrode 2 and the parasitic radiation electrode 3, as shown by the solid line I in FIG. The current flows along a path that flows along the direction in which the main surface portions 2M and 3M are arranged (the direction along the short side of the substrate) and then flows along the long side of the substrate. On the other hand, when the ground electrode portions 2G and 3G do not come out of their own regions as shown in FIG. 3B, the current induced in the substrate 4 is indicated by a dotted line i in FIG. Electricity is supplied through such a straight path along the long side of the substrate. Due to such a difference in the path of the induced current of the substrate 4, in the configuration of the first embodiment, the path length of the induced current can be lengthened, so that the function of the substrate 4 as an antenna by the induced current can be enhanced. . This contributes to broadening the band, improving antenna efficiency, and improving the pattern averaging gain that emphasizes polarization perpendicular to the ground during a call when the multi-resonant antenna structure 1 is built in a mobile phone. are doing.
[0054]
Hereinafter, a second embodiment will be described. In the description of the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the overlapping description of the common portions will be omitted.
[0055]
The multiple resonance antenna structure 1 of the second embodiment is shown in a schematic perspective view of FIG. FIG. 9B is a schematic side view of the multiple resonance antenna structure 1 viewed from the right side of FIG. 9A. 9C, the feed radiation electrode 2 and the parasitic radiation electrode 3 are extracted and shown in a developed view.
[0056]
In the second embodiment, a ground-connecting plate-like member 20 protruding from a short-side end surface of the substrate 4 in a direction along the long side of the substrate is provided. The grounding electrode portions 2G and 3G of the feeding radiation electrode 2 and the parasitic radiation electrode 3 of the multiple resonance antenna structure 1 are connected to the edge portions of the substrate 4 instead of connecting to the edge portions of the substrate 4, respectively. 20 are connected to the protruding tips. In the second embodiment, a connection body between the feed radiation electrode 2 and the parasitic radiation electrode 3 and the ground connection plate member 20 is formed in a loop shape. In other words, the connection body has a loop-shaped path surrounding the end surface of the substrate 4 while the end of the ground-connecting plate member 20 is connected to the end surface of the substrate 4 and swells in a direction away from the substrate 4 with the connection portion as a starting point. As a result, it is wrapped around the surface side of the substrate 4 and is arranged at an interval from the surface of the substrate 4.
[0057]
Also in the second embodiment, similarly to the first embodiment, the ground electrode portion 2G of the feeding radiation electrode 2 extends from the feeding radiation electrode 2 side to the non-feeding radiation electrode 3 side, and the extended tip portion has no extension. It is connected to the ground connecting plate member 20 on the side of the feed radiation electrode 3. The ground electrode portion 3G of the parasitic radiation electrode 3 is disposed closer to the substrate 4 than the ground electrode portion 2G of the feed radiation electrode 2, and the ground electrode portion 3G is fed from the parasitic radiation electrode 3 side. The extension tip extends to the radiation electrode 2 side and is connected to the ground connection plate-like member 20 on the feed radiation electrode 2 side, and the grounding electrode portions 2G and 3G of the feed radiation electrode 2 and the parasitic radiation electrode 3 are connected to each other. Are arranged so that a part of the electrode surface faces each other. A dielectric 7 is interposed between the ground electrode portions 2G and 3G.
[0058]
In the second embodiment, the board 4 functions as a circuit board of a communication device, and the multiple resonance antenna structure 1 is disposed at an end of the board 4 and is housed together with the board 4 in a housing of the communication device. Be placed. In some cases, the housing of the communication device is tapered in a direction of narrowing to an end portion for design. In the second embodiment, the shape of the casing of the communication device is considered. That is, in each of the main surface portions 2M and 3M of the feeding radiation electrode 2 and the parasitic radiation electrode 3, the portion B (see FIG. 9B) protruding from the substrate 4 is provided with the ground connection plate member 20. An inclination is provided such that the distance from the protruding tip end side (the side where the grounding electrode portion is formed) becomes narrower with respect to the ground connection plate member 20. The inclination of the main surface portions 2M and 3M is adjusted to the taper of the end of the housing of the communication device. The multiple resonance antenna structure 1 of the second embodiment is provided at the end of the housing of the communication device. The configuration is such that it can be fitted together and dead space at the end of the housing of the communication device can be eliminated.
[0059]
Further, the open end 2oe of the main surface portion 2M of the feed radiation electrode 2 is arranged in an edge region on the long side on the right side of the substrate 4 shown in FIG. Further, the open end 3oe of the main surface portion 3M of the parasitic radiation electrode 3 is arranged in an edge region on the long side of the left side of the substrate 4 shown in FIG. 9A.
[0060]
That is, in the second embodiment, the connection portion P between the ground electrode portions 2G, 3G and the ground connection plate member 20 in the area allowed as the antenna formation area. 2g , P 3g The open ends 2 oe and 3 oe of the feeding radiation electrode 2 and the non-feed radiation electrode 3 are disposed at portions farthest from the feeding radiation electrode 2 and the non-feed radiation electrode 3. Thus, the portion P where the ground electrode portions 2G and 3G are connected to the ground connecting plate member 20 in the antenna formation region regulated in advance. 2g , P 3g To the open ends 2oe and 3oe can be made longer. For this reason, the electrical length of the feed radiation electrode 2 and the parasitic radiation electrode 3 can be increased. Thus, it is possible to reduce the size of the feed radiation electrode 2 and the parasitic radiation electrode 3 while maintaining a wide band.
[0061]
Further, in the second embodiment, the feed radiation electrode 2 and the parasitic radiation electrode 3 are disposed in the portion where the open ends 2oe and 3oe are formed, that is, in the edge region on the long side of the substrate 4. The inclined portion is inclined such that the distance from the substrate 4 becomes narrower toward the edge on the long side of the substrate 4. This inclination is also adapted to the taper at the end of the housing of the communication device, as described above.
[0062]
Further, in the second embodiment, a hole 21 is formed at least in the central region of the ground-connecting plate-shaped member 20, and a part of the communication device can be arranged in the portion where the hole 21 is formed. It has a configuration that can be used. For example, when the multi-resonance antenna structure 1 of the second embodiment is incorporated in a mobile phone, the substrate 4 of the multi-resonance antenna structure 1 is formed as a circuit board of the mobile phone, The feed radiation electrode 3 is disposed at the top end of the circuit board that is on the zenith side during a call. A speaker is provided on the top side of the mobile phone, and, for example, a component of the speaker is disposed inside a hole 21 formed in the plate member 20 for ground connection of the multiple resonance antenna structure 1.
[0063]
In the second embodiment, the feeding radiation electrode 2 and the parasitic radiation electrode 3 have the grounding electrode portions 2G and 3G having the unique configuration shown in the first embodiment, and the feeding radiation electrode 2 The parasitic radiation electrode 3 and the parasitic radiation electrode 3 are connected to the protruding distal end of the plate member 20 for ground connection, and the connection body between the radiation electrode 2 and the parasitic radiation electrode 3 and the plate member 20 for ground connection is a substrate. 4 has a loop-like shape that goes from one side to the other side of the front surface and the back surface, so that the physical volumes of the feed radiation electrode 2 and the parasitic radiation electrode 3 can be increased, And antenna characteristics such as antenna efficiency can be greatly improved.
[0064]
Hereinafter, a third embodiment will be described. The third embodiment relates to a communication device. A characteristic of the communication device of the third embodiment is that one of the multiple resonance antenna structures 1 shown in the first and second embodiments is provided as an antenna. . There are various configurations of the communication device other than the antenna configuration. Here, any configuration other than the antenna may be employed. Further, the description of the multiple resonance antenna structure 1 provided in the communication device of the third embodiment has been described in the first or second embodiment, and the description thereof will be omitted.
[0065]
Note that the present invention is not limited to the first to third embodiments, but can adopt various embodiments. For example, in the first embodiment, a slit 10 for adjusting the resonance frequency is provided in one of the fed radiation electrode 2 and the parasitic radiation electrode 3, and the slit 10 for adjusting the resonance frequency is provided in the second embodiment. The slit 10 for adjusting the resonance frequency is provided in the feeding radiation electrode 2 on the other side. For example, as shown in FIG. 10, both the feeding radiation electrode 2 and the parasitic radiation electrode 3 are used for adjusting the resonance frequency. A slit 10 may be formed.
[0066]
Further, in the second embodiment, the ground-connecting plate-shaped member 20 is connected to the end face of the substrate 4. However, for example, as shown in FIG. The ground connecting plate member 20 is disposed so as to protrude from the end surface of the substrate 4, and the grounding electrode portions 2 </ b> G of the feeding radiation electrode 2 and the non-feeding radiation electrode 3 are provided at the protruding tips of the ground connection plate member 20. , 3G may be connected to each other.
[0067]
The multi-resonant antenna structure 1 shown in FIG. 10 is built in the portable telephone, and the multi-resonant antenna structure 1 is arranged at the top end of the circuit board of the portable telephone which is on the zenith side during a call. Is established. Each of the main surface portions 2M and 3M of the feed radiation electrode 2 and the parasitic radiation electrode 3 has a part of an edge portion arranged in an edge region on the long side of the substrate 4, and the long side of the substrate. The edge portion disposed in the edge region on the side is inclined such that the distance from the substrate surface decreases toward the edge on the long side of the substrate. That is, the inclination is set according to the shape of the housing in which the substrate 4 is accommodated.
[0068]
Further, in the second embodiment, the connection body between the feed radiation electrode 2 and the parasitic radiation electrode 3 and the plate member 20 for ground connection is formed in a loop shape surrounding the edge of the substrate 4. As shown in FIG. 11, only the feeding radiation electrode 2 and the parasitic radiation electrode 3 may be formed in a loop shape surrounding the edge of the plate member 20 for ground connection (the edge of the substrate 4). Further, the configuration may be such that the ground-connecting plate-like member 20 is omitted, and the loop-shaped feeding radiation electrode 2 and the parasitic radiation electrode 3 as shown in FIG. .
[0069]
Furthermore, in each of the first to third embodiments, the ground electrode portions 2G and 3G of the feed radiation electrode 2 and the parasitic radiation electrode 3 are respectively provided on the substrate surface 4a (the plate member 20 for ground connection). Although it stands in the direction perpendicular to the direction, for example, as shown in FIG. 12, the ground electrode portions 2G and 3G may be inclined with respect to the substrate surface 4a (the plate member 20 for ground connection). .
[0070]
Further, in each of the first to third embodiments, the feed radiation electrode 2 and the parasitic radiation electrode 3 are arranged at the end of the substrate 4, and each of the ground electrode portions 2 </ b> G, 3 </ b> G is located at the edge of the substrate 4. However, for example, even if the feed radiation electrode 2 and the parasitic radiation electrode 3 are provided in a portion other than the end of the substrate 4, the feed radiation electrode 2 and the parasitic radiation electrode 3 If the path length of the current induced in the substrate 4 can be made sufficiently long, the feed radiation electrode 2 and the parasitic radiation electrode 3 may be provided at a portion other than the end of the substrate 4.
[0071]
Further, although the substrate 4 has a rectangular shape, a substrate 4 having a shape other than the rectangular shape may be used.
[0072]
【The invention's effect】
According to the present invention, the main surface portion of the feed radiation electrode and the main surface portion of the parasitic radiation electrode are adjacently arranged side by side in the horizontal direction with an interval therebetween, and from an edge portion which is a short connection side of each of the main surface portions, Each is provided with a grounding electrode portion that extends and connects to the substrate. The ground electrode portion of the feed radiation electrode extends from the feed radiation electrode side to the parasitic radiation electrode side, and the extended tip is connected to the substrate portion on the parasitic radiation electrode side. In addition, the grounding electrode portion of the parasitic radiation electrode extends from the parasitic radiation electrode side to the feeding radiation electrode side, and the extended end portion is connected to the substrate portion on the feeding radiation electrode side. The grounding electrode portions of the electrode are arranged so that a part of the electrode surface faces each other with a space therebetween.
[0073]
The capacitance generated between the ground electrode portion of the feed radiation electrode and the ground electrode portion of the parasitic radiation electrode is related to the amount of electromagnetic coupling between the feed radiation electrode and the parasitic radiation electrode. In the present invention, a part of the electrode surface of each of the grounding electrode portions of the feed radiation electrode and the parasitic radiation electrode is configured to face each other with an interval therebetween. For this reason, in the present invention, compared to the conventional case where the electrode surfaces of the grounding electrode portions of the feeding radiation electrode and the parasitic radiation electrode are not opposed to each other and are arranged side by side, the grounding electrode portion of the feeding radiation electrode in the present invention. And the capacitance between the parasitic radiation electrode and the grounding electrode portion can be increased. This increases the degree to which the capacitance between the feeding radiation electrode and the grounding electrode portion of the parasitic radiation electrode contributes to the amount of electromagnetic coupling between the feeding radiation electrode and the parasitic radiation electrode. Therefore, it is easy to adjust the amount of electromagnetic coupling between the feeding radiation electrode and the parasitic radiation electrode by variably adjusting the capacitance, and the variable range of the capacitance can be expanded by increasing the capacitance. Thus, the range of the electromagnetic coupling amount adjustment by the capacitance adjustment can be expanded.
[0074]
In other words, the capacitance between the grounding electrode part of the feeding radiation electrode and the grounding electrode part of the parasitic radiation electrode functions as a coupling amount adjustment unit that adjusts the electromagnetic coupling between the feeding radiation electrode and the parasitic radiation electrode. can do.
[0075]
Further, the adjustment of the amount of electromagnetic coupling by adjusting the capacitance uses the ground electrode portion instead of the main surface portion, and the ground electrode portion has a higher degree of freedom in design than the main surface portion. Therefore, adjustment of the amount of electromagnetic coupling between the feeding radiation electrode and the parasitic radiation electrode using the capacitance between the grounding electrode portions of the feeding radiation electrode and the parasitic radiation electrode is performed by adjusting the amount of electromagnetic coupling using the main surface portion. Can be performed more easily than in the case where
[0076]
Furthermore, it has been confirmed by the present inventors that the adjustment of the amount of electromagnetic coupling by adjusting the capacitance between the feeding radiation electrode and the grounding electrode portion of the parasitic radiation electrode can be performed quantitatively and accurately. .
[0077]
The multiple resonance state of the feed radiation electrode and the parasitic radiation electrode is determined by the state of electromagnetic coupling between the feed radiation electrode and the parasitic radiation electrode. According to the present invention, as described above, the amount of electromagnetic coupling between the feed radiation electrode and the parasitic radiation electrode can be controlled easily and with high accuracy, so that the antenna characteristics of the feed radiation electrode and the parasitic radiation electrode can be improved. An appropriate multiple resonance state can be easily obtained. That is, it is possible to provide a multiple resonance antenna structure excellent in antenna characteristics and a communication device including the same.
[0078]
Further, in the present invention, the ground electrode portion is not connected to the main surface portion and the substrate at the shortest distance as in the related art, but from the feed radiation electrode side to the parasitic radiation electrode side, or from the parasitic radiation electrode side. It extends to the feeding radiation electrode side, and the extended tip is connected to the substrate. Therefore, by providing the configuration of the present invention, the length of the ground electrode portion can be increased.
[0079]
Due to the extension of the ground electrode portion, the electrical lengths of the feeding radiation electrode and the parasitic radiation electrode can be increased. Thus, the conventional one provided with the grounding electrode portion for connecting the substrate and the main surface portion at the shortest distance, and the one provided with the configuration of the present invention in which the grounding electrode portion is extended. In order to satisfy the same bandwidth and antenna efficiency, by providing the configuration of the present invention, the area of the main surface can be reduced. That is, the size of the multiple resonance antenna structure can be reduced, and the communication device including the multiple resonance antenna structure of the present invention can be reduced in size with the reduction in the size of the multiple resonance antenna structure.
[0080]
Furthermore, since the electrical length of each of the feed radiation electrode and the parasitic radiation electrode can be increased by extending the ground electrode portion, the following effects can be obtained. For example, as one of the techniques for reducing the size of the feeding radiation electrode and the parasitic radiation electrode, there is a method of forming a dielectric between the main surface and the substrate to increase the dielectric constant between the main surface and the substrate. In the present invention, the electrical length of the feed radiation electrode and the parasitic radiation electrode can be increased without changing the antenna volume by extending the ground electrode portion, so that the dielectric between the main surface portion and the substrate can be increased. Can be reduced. For this reason, it is possible to prevent the frequency band from being narrowed due to the dielectric, and to widen the communication frequency band. In addition, material costs can be reduced.
[0081]
Furthermore, in the present invention, the ground electrode portion extends from the feed radiation electrode side to the parasitic radiation electrode side, or extends from the parasitic radiation electrode side to the feed radiation electrode side, and the extended tip portion is connected to the substrate. Has become. Therefore, the current induced in the substrate based on the current flowing through the feeding radiation electrode or the parasitic radiation electrode is similar to or close to the direction in which the main surface portions of the feeding radiation electrode and the parasitic radiation electrode are juxtaposed. After flowing to the substrate with the orientation, the direction is changed, and the induced current flows through the substrate in a direction from the side of the main surface of the feed radiation electrode or the parasitic radiation electrode where the grounding electrode portion is formed to the open end side. The path length of the induced current can be increased by such a path of the induced current, so that the antenna function of the substrate by the induced current can be enhanced. This makes it possible to widen the frequency band, improve antenna efficiency, and improve the pattern averaging gain.
[0082]
Further, in the present invention, the main surface portions of the feed radiation electrode and the parasitic radiation electrode are configured to be adjacently arranged in the horizontal direction. For this reason, the main surface portions of both the feeding radiation electrode and the parasitic radiation electrode can be arranged at the highest position, for example, within the height limit determined by the specification or the like. Thus, it is possible to reduce the adverse effect of both the main surface of the feed radiation electrode and the main surface of the parasitic radiation electrode from the substrate (that is, the ground). In other words, when the main surface portion is close to the substrate, the antenna gain is likely to be reduced due to the adverse effect of the ground. However, by providing the configuration of the present invention, the main surface portion of the feed radiation electrode and the main surface portion of the parasitic radiation electrode are reduced. Since both can be separated from the substrate, adverse effects from the ground are reduced, and the antenna gain can be improved.
[0083]
In the case where a dielectric is provided in a gap between the grounding electrode part of the feeding radiation electrode and the grounding electrode part of the parasitic radiation electrode, the grounding electrode part of the feeding radiation electrode and the parasitic radiation electrode is used. The capacity between the feeding radiation electrode and the grounding electrode portion of the non-feeding radiation electrode can be easily increased as compared with the case where there is a gap. That is, the range in which the capacitance between the feeding radiation electrode and the grounding electrode portion of the parasitic radiation electrode can be adjusted can be expanded, and the adjustment of the electromagnetic coupling amount between the feeding radiation electrode and the parasitic radiation electrode becomes easier.
[0084]
In the case where the non-electrode portion is formed at one or both of the grounding electrode portions of the feeding radiation electrode and the parasitic radiation electrode, the non-electrode portion is formed between the feeding radiation electrode and the non-feeding radiation electrode. The capacitance between the feeding radiation electrode and the ground electrode portion of the parasitic radiation electrode can be reduced without increasing the distance between the electrodes. In other words, if an attempt is made to widen the space between the feeding radiation electrode and the grounding electrode portion of the parasitic radiation electrode, one of the feeding radiation electrode and the parasitic radiation electrode may not be formed due to, for example, the regulation of the antenna formation area according to specifications. A situation may arise in which the area of the side main surface must be reduced. In such a case, a problem such as a decrease in antenna gain due to a decrease in the area of the main surface may occur. On the other hand, in the present invention, the non-electrode portion is formed at one or both of the grounding electrode portions of the feeding radiation electrode and the parasitic radiation electrode, so that the grounding electrode of the feeding radiation electrode and the parasitic radiation electrode is formed. The amount of electromagnetic coupling between the feed radiation electrode and the parasitic radiation electrode can be adjusted without increasing the interval between the parts. Therefore, it is possible to avoid the above-described problem of a decrease in antenna gain due to a decrease in the area of the main surface.
[0085]
In each of the feeding radiation electrode and the non-feeding radiation electrode, the one where the edge portion of the main surface portion that is electrically farthest from the portion where the ground electrode portion is connected to the substrate is an open end, The electrical length of each of the feed radiation electrode and the parasitic radiation electrode can be made longer. Thereby, it is possible to further improve the antenna characteristics such as the antenna efficiency as described above.
[0086]
In the case where a dielectric is interposed between the open end and the substrate at one or both open ends of the feed radiation electrode and the parasitic radiation electrode, the capacitance between the open end and the substrate is increased. can do. Also in this case, the feed radiation electrode or the parasitic radiation electrode can be reduced in size due to the wavelength shortening effect.
[0087]
In the case where a slit is formed in one or both of the feeding radiation electrode and the non-feeding radiation electrode, adjustment of the resonance frequency on the higher-order side becomes easy. For this reason, it is possible to easily cope with multiband operation. Further, in the case where a dielectric is formed in the slit, the resonance frequency of the radiation electrode using the slit can be more easily adjusted, and the multiband operation can be more easily achieved.
[0088]
Furthermore, the grounding electrode portions of the feeding radiation electrode and the parasitic radiation electrode are connected to the edge portion of the substrate, and those connected to the short edge portion of the rectangular substrate. In addition, the substrate can be easily made to function as a part of the antenna by the current induced in the substrate due to the current flowing through the feeding radiation electrode or the parasitic radiation electrode.
[0089]
Further, in the case where the main surface of the feeding radiation electrode or the parasitic radiation electrode is inclined, for example, the inclination corresponding to the tapered shape of the housing of the communication device is adjusted to the main surface of the feeding radiation electrode or the parasitic radiation electrode. By providing the surface portion, the feed radiation electrode and the parasitic radiation electrode can be arranged along the inner wall surface of the tapered portion of the housing. Thereby, a dead space caused by the tapered shape of the housing can be eliminated.
[0090]
Further, a feed radiation electrode and a parasitic radiation electrode, or a connection body between the feed radiation electrode and the parasitic radiation electrode, and the ground-connecting plate-shaped member 20 may be arranged such that the edge of the substrate is arranged from one side of the front surface and the back surface of the substrate. In the case of a loop shape that goes around the other substrate surface side through the surrounding loop-shaped path, it becomes easy to make the electrical length of the feed radiation electrode and the parasitic radiation electrode longer, and the antenna The characteristics can be further improved.
[0091]
In the communication device having the multiple resonance antenna structure of the present invention, the communication reliability is high and the communication device is small because the multiple resonance antenna structure having the above-described excellent effects is provided. Can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a multiple resonance antenna structure according to a first embodiment.
2 is a view of the multiple resonance antenna structure shown in FIG. 1 as viewed from a direction a shown in FIG.
FIG. 3 is a diagram for explaining grounding electrode portions of a feed radiation electrode and a parasitic radiation electrode shown in the first embodiment.
FIG. 4 is a view for explaining another embodiment of the ground electrode portions of the feed radiation electrode and the parasitic radiation electrode.
FIG. 5 is a model diagram showing a multiple resonance antenna structure used in an experiment performed by the present inventors.
FIG. 6 is a graph showing the results of an experiment performed by the present inventors.
FIG. 7 is a diagram for explaining a pattern averaging gain.
FIG. 8 is a diagram illustrating an example of a path of a current induced in a substrate due to a current flowing through a feeding radiation electrode or a parasitic radiation electrode.
FIG. 9 is a diagram for explaining a multiple resonance antenna structure according to a second embodiment.
FIG. 10 is a diagram for explaining another embodiment.
FIG. 11 is a side view showing another embodiment of the feeding radiation electrode and the parasitic radiation electrode in a loop shape.
FIG. 12 is a view for explaining another embodiment of the ground electrode portions of the feed radiation electrode and the parasitic radiation electrode.
FIG. 13 is a diagram for explaining one of the antenna structures described in Patent Document 1.
FIG. 14 is a diagram for explaining one of the antenna structures described in Patent Document 2.
[Explanation of symbols]
1 Double resonance antenna structure
2 Feeding radiation electrode
3 Parasitic radiation electrode
2M, 3M main surface
2G, 3G Ground electrode part
4 Substrate
7,8 Dielectric
10 slits
11 holes
12 Notch
20 Plate member for ground connection

Claims (17)

複共振状態を作り出す給電放射電極と無給電放射電極が互いに間隔を介してグランドと等価な基板に配設されている複共振アンテナ構造であって、給電放射電極と無給電放射電極は、それぞれ、基板面と間隔を介して配置される主面部を有し、これら給電放射電極の主面部と、無給電放射電極の主面部とは互いに水平方向に間隔を介して隣接並設され、当該給電放射電極と無給電放射電極の各主面部のショート接続側となる端縁部分から、それぞれ、伸設して基板に接続する接地用電極部位が設けられ、その給電放射電極の接地用電極部位は当該給電放射電極側から無給電放射電極側に伸び当該伸長先端部が無給電放射電極側の基板部分に接続され、また、無給電放射電極の接地用電極部位は当該無給電放射電極側から給電放射電極側に、給電放射電極の接地用電極部位と間隔を介し近接配置しながら伸び当該伸長先端部が給電放射電極側の基板部分に接続されており、給電放射電極と無給電放射電極の各接地用電極部位は、基板との接続部から主面部との連接部に至るまでの経路の一部が添設されていることを特徴とする複共振アンテナ構造。A multi-resonant antenna structure in which a feed radiation electrode and a parasitic radiation electrode that create a multiple resonance state are disposed on a substrate equivalent to ground with an interval therebetween, and the feed radiation electrode and the parasitic radiation electrode are respectively: A main surface portion disposed at an interval from the substrate surface; the main surface portion of the feed radiation electrode and the main surface portion of the parasitic radiation electrode are horizontally adjacent to each other with an interval therebetween, and A grounding electrode portion is provided to extend from the edge portion of each main surface of the electrode and the parasitic radiation electrode on the short connection side, and is connected to the substrate. The extending tip extends from the feeding radiation electrode side to the parasitic radiation electrode side, and the extended tip is connected to the substrate portion on the parasitic radiation electrode side, and the ground electrode portion of the parasitic radiation electrode is fed radiation from the parasitic radiation electrode side. At the electrode side, The extended distal end portion is connected to the substrate portion on the side of the feeding radiation electrode while extending in close proximity to the grounding electrode portion of the radiation electrode with an interval therebetween, and each of the grounding electrode portions of the feeding radiation electrode and the parasitic radiation electrode is A multi-resonant antenna structure, wherein a part of a path from a connection portion with a substrate to a connection portion with a main surface portion is additionally provided. 給電放射電極の接地用電極部位と、無給電放射電極の接地用電極部位との間の間隙に生じる容量は、給電放射電極と無給電放射電極間の電磁結合量を調整する結合量調整部と成していることを特徴とする請求項１記載の複共振アンテナ構造。A capacitance generated in a gap between the grounding electrode part of the feeding radiation electrode and the grounding electrode part of the parasitic radiation electrode includes a coupling amount adjusting unit that adjusts an electromagnetic coupling amount between the feeding radiation electrode and the parasitic radiation electrode. The multi-resonant antenna structure according to claim 1, wherein the structure is formed. 給電放射電極の接地用電極部位と、無給電放射電極の接地用電極部位との間の間隙には誘電体が介設されていることを特徴とする請求項１又は請求項２記載の複共振アンテナ構造。3. The multiple resonance according to claim 1, wherein a dielectric is interposed in a gap between the ground electrode portion of the feed radiation electrode and the ground electrode portion of the parasitic radiation electrode. Antenna structure. 給電放射電極の接地用電極部位と、無給電放射電極の接地用電極部位とのうちの一方又は両方には、非電極部が形成されていることを特徴とする請求項１又は請求項２又は請求項３記載の複共振アンテナ構造。The non-electrode part is formed in one or both of the grounding electrode part of the feeding radiation electrode and the grounding electrode part of the parasitic radiation electrode, wherein the non-electrode part is formed. The multiple resonance antenna structure according to claim 3. 給電放射電極と無給電放射電極のそれぞれにおいて、接地用電極部位が基板に接続している部分から電気的に最も離れた主面部の端縁部分が開放端と成していることを特徴とする請求項１乃至請求項４の何れか１つに記載の複共振アンテナ構造。In each of the feeding radiation electrode and the non-feeding radiation electrode, an edge portion of a main surface portion that is electrically farthest from a portion where the grounding electrode portion is connected to the substrate is an open end. The multiple resonance antenna structure according to claim 1. 給電放射電極の開放端と無給電放射電極の開放端とのうちの一方又は両方において、開放端と基板間の間隙に誘電体が介設されていることを特徴とする請求項５記載の複共振アンテナ構造。6. The multi-layer structure according to claim 5, wherein a dielectric is provided in a gap between the open end and the substrate at one or both of the open end of the feed radiation electrode and the open end of the parasitic radiation electrode. Resonant antenna structure. 給電放射電極と無給電放射電極のうちの一方又は両方には、当該放射電極の共振周波数を調整するスリットが形成されていることを特徴とする請求項１乃至請求項６の何れか１つに記載の複共振アンテナ構造。The slit for adjusting the resonance frequency of the radiation electrode is formed on one or both of the feed radiation electrode and the parasitic radiation electrode, according to any one of claims 1 to 6, wherein A multi-resonant antenna structure as described. スリットには誘電体が介設されていることを特徴とする請求項７記載の複共振アンテナ構造。The multiple resonance antenna structure according to claim 7, wherein a dielectric is interposed in the slit. 給電放射電極の接地用電極部位と、無給電放射電極の接地用電極部位とは、それぞれ、基板の端縁部に接続していることを特徴とする請求項１乃至請求項８の何れか１つに記載の複共振アンテナ構造。The grounding electrode part of the feeding radiation electrode and the grounding electrode part of the parasitic radiation electrode are connected to the edge of the substrate, respectively. The multiple resonance antenna structure according to any one of the first to third aspects. 基板の端面よりも基板面に沿う方向に突出したグランド接続用板状部材が設けられており、給電放射電極の接地用電極部位と、無給電放射電極の接地用電極部位とは、それぞれ、基板に接続するのに代えて、そのグランド接続用板状部材の突出先端部分に接続していることを特徴とする請求項１乃至請求項８の何れか１つに記載の複共振アンテナ構造。A ground-connecting plate-like member protruding in a direction along the substrate surface from an end surface of the substrate is provided, and a grounding electrode portion of the feeding radiation electrode and a grounding electrode portion of the parasitic radiation electrode are respectively provided on the substrate. 9. The multi-resonant antenna structure according to claim 1, wherein the antenna is connected to a protruding tip portion of the ground-connecting plate member instead of being connected to the ground. 基板は長方形状と成し、給電放射電極と無給電放射電極の各主面部は基板の短辺に沿う方向に間隔を介して並設され、給電放射電極と無給電放射電極の各接地用電極部位は、基板の短辺側の端縁部分に接続するか、又は、その基板短辺側の端面よりも基板長辺に沿う方向に突出形成されたグランド接続用板状部材の突出先端部分に接続する構成と成していることを特徴とする請求項１乃至請求項８の何れか１つに記載の複共振アンテナ構造。The substrate has a rectangular shape, and the main surface portions of the feeding radiation electrode and the parasitic radiation electrode are arranged side by side in the direction along the short side of the substrate with an interval therebetween, and each ground electrode of the feeding radiation electrode and the parasitic radiation electrode is provided. The portion is connected to the edge portion on the short side of the substrate, or at the protruding tip portion of the ground connection plate member formed so as to protrude in a direction along the long side of the substrate from the end surface on the short side of the substrate. The multi-resonant antenna structure according to any one of claims 1 to 8, wherein the multi-resonant antenna structure is configured to be connected. 給電放射電極の主面部と無給電放射電極の主面部とのうちの一方又は両方において、主面部の端縁部の一部分は基板の長辺側の端縁領域に配置されており、この基板長辺側端縁領域に配置されている主面部の端縁部分には、基板長辺側の端縁に向かうに従って基板面との間隔が狭くなる傾きが付けられていることを特徴とする請求項１１記載の複共振アンテナ構造。In one or both of the main surface portion of the feed radiation electrode and the main surface portion of the parasitic radiation electrode, a part of the edge portion of the main surface portion is disposed in an edge region on the long side of the substrate. The edge portion of the main surface portion arranged in the side edge region is inclined so that the distance from the substrate surface decreases toward the edge on the long side of the substrate. 12. The multiple resonance antenna structure according to 11. 給電放射電極と無給電放射電極の各主面部のそれぞれにおいて、少なくとも接地用電極部位形成側の部位には、接地用電極部位形成側の端縁に向かうに従って基板面又はグランド接続用板状部材との間隔が狭くなる傾きが付けられていることを特徴とする請求項９又は請求項１０又は請求項１１又は請求項１２記載の複共振アンテナ構造。In each of the main surface portions of the feed radiation electrode and the parasitic radiation electrode, at least a portion on the side where the ground electrode portion is formed has a substrate surface or a plate member for ground connection as it goes toward the edge on the side where the ground electrode portion is formed. 13. The multi-resonant antenna structure according to claim 9, wherein an inclination of the space is narrowed. 給電放射電極と無給電放射電極は、それぞれ、接地用電極部位が基板又はグランド接続用板状部材に接続している部分を起点として基板から離れる方向に膨らみながら基板端縁を囲むループ状の経路を通って起点とは反対側の基板面に間隔を介し沿うように形成された主面部に接続される態様と成していることを特徴とする請求項１乃至請求項１３の何れか１つに記載の複共振アンテナ構造。The feeding radiation electrode and the parasitic radiation electrode each have a loop-shaped path surrounding the edge of the substrate while expanding in a direction away from the substrate from a portion where the ground electrode portion is connected to the substrate or the plate member for ground connection. 14. The semiconductor device according to any one of claims 1 to 13, wherein the substrate is connected to a main surface portion formed so as to extend along the substrate surface opposite to the starting point with a gap therebetween. 2. The multiple resonance antenna structure according to item 1. 基板の端面よりも基板面に沿う方向に突出したグランド接続用板状部材が設けられており、給電放射電極の接地用電極部位と、無給電放射電極の接地用電極部位とは、それぞれ、基板に接続するのに代えて、そのグランド接続用板状部材の突出先端部分に接続されている構成と成し、給電放射電極および無給電放射電極と、グランド接続用板状部材との接続体は、グランド接続用板状部材側の端部が基板に接続され当該接続部分を起点として基板から離れる方向に膨らみながら基板端縁を囲むループ状の経路を通って基板面に間隔を介し沿うように配置される態様と成していることを特徴とする請求項１０乃至請求項１３の何れか１つに記載の複共振アンテナ構造。A ground-connecting plate-like member protruding in a direction along the substrate surface from an end surface of the substrate is provided, and a grounding electrode portion of the feeding radiation electrode and a grounding electrode portion of the parasitic radiation electrode are respectively provided on the substrate. Instead of being connected to the ground connection plate-shaped member, the grounded plate-shaped member is connected to the protruding tip portion. The end on the side of the ground-connecting plate member is connected to the substrate, and swells in a direction away from the substrate with the connection portion as a starting point. The multiple resonance antenna structure according to any one of claims 10 to 13, wherein the multiple resonance antenna structure is arranged. 請求項１乃至請求項１５の何れか一つに記載の複共振アンテナ構造が設けられていることを特徴とする通信機。A communication device comprising the multiple resonance antenna structure according to claim 1. 通信機は携帯型電話機と成しており、複共振アンテナ構造は、通話中に天頂側となる携帯型電話機の回路基板のトップ側端部に設けられていることを特徴とする請求項１６記載の通信機。17. The communication device according to claim 16, wherein the communication device is a portable telephone, and the multiple resonance antenna structure is provided at a top end of a circuit board of the portable telephone which is on the zenith side during a call. Communicator.
JP2003084377A 2003-03-26 2003-03-26 Multi-resonant antenna structure and communication device including the same Expired - Fee Related JP3922200B2 (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004312364A (en) * 2003-04-07 2004-11-04 Murata Mfg Co Ltd Antenna structure and communication apparatus provided therewith
JP2014072609A (en) * 2012-09-28 2014-04-21 Harada Ind Co Ltd Low-profile antenna device
CN113412557A (en) * 2019-02-08 2021-09-17 株式会社村田制作所 Antenna module and communication device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004312364A (en) * 2003-04-07 2004-11-04 Murata Mfg Co Ltd Antenna structure and communication apparatus provided therewith
JP2014072609A (en) * 2012-09-28 2014-04-21 Harada Ind Co Ltd Low-profile antenna device
CN113412557A (en) * 2019-02-08 2021-09-17 株式会社村田制作所 Antenna module and communication device
CN113412557B (en) * 2019-02-08 2024-02-02 株式会社村田制作所 Antenna module and communication device

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