JP3746281B2

JP3746281B2 - ANTENNA DEVICE AND PORTABLE RADIO COMMUNICATION DEVICE

Info

Publication number: JP3746281B2
Application number: JP2003196034A
Authority: JP
Inventors: 聡溝口; 隆天野
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 2003-07-11
Filing date: 2003-07-11
Publication date: 2006-02-15
Anticipated expiration: 2023-07-11
Also published as: JP2005033491A

Description

【０００１】
【発明の属する技術分野】
本発明はアンテナ装置及び携帯無線通信装置に係り、特に携帯無線通信装置の本体に内蔵することができるアンテナ装置及び当該携帯無線通信装置に関する。
【０００２】
【従来の技術】
携帯無線通信装置用のアンテナは、これまでの主流であった使用時に筐体外部に引き出せるように実装されるホイップ型アンテナに類似したタイプから、内蔵型のタイプに移行しつつある。内蔵型アンテナを用いることにより、使用時及び収納時の取り扱いが、従来のタイプのアンテナを用いる場合に比べてはるかに容易になり、また筐体デザインの自由度が増す等の利点があるが、中でも筐体をさらに薄く構成することができるという利点が大きい。
【０００３】
しかし、内蔵型アンテナとして従来一般的であった板状逆Ｆアンテナや、シンプルな構成のダイポールアンテナは、携帯無線通信装置の正面方向（使用者の方向）にも放射パターンが形成されることにより不整合損及び誘電体損を生じて、放射効率が低下するという問題があった。このような問題点を改善するため、ダイポールアンテナにより構成された主アンテナに無給電の対向素子を組み合せて配置するという発明がなされている（例えば、特許文献１参照。）。この特許文献１に開示された発明は、主アンテナを受話器を取り付けた面に平行に配置すると共に、その面に垂直な方向に一定値以上の距離を置いて主アンテナに平行に対向素子を配置するというものである。
【０００４】
一方、周波数特性の広帯域化も、内蔵型アンテナの重要な課題の一つである。この面では、共振周波数を偏移させた寄生素子を主アンテナに近接配置してアンテナを構成する方法が従来から知られており、携帯無線通信装置等に応用できるようその小型化を図った発明もなされている（例えば、特許文献２又は特許文献３参照。）。この特許文献２に開示された発明は、誘電体からなる直方体の主面に斜めに設けたスリットを挟んで２つの表面電極を対向させて主アンテナ及び寄生素子として用いることにより、小型化と広帯域化を図るというものである。また、特許文献３に開示された発明は、誘電体の表面に一端開放、他端給電、線長４分の１波長の線状の主アンテナと、その４０％以下の線長を有する寄生素子を設けてアンテナを構成し、小型化と広帯域化を図るというものである。
【０００５】
【特許文献１】
特開２００２−９５３４号公報（第２、６、７、１１、１２ページ、図６６）
【０００６】
【特許文献２】
特許第３３５１３６３号公報（第２、３ページ、図１）
【０００７】
【特許文献３】
特開２００２−３４４２２２号公報（第２ページ、図１）
【０００８】
【発明が解決しようとする課題】
携帯無線通信装置においては、各種の情報機器又は通信機器の中でも、とりわけ小型化、薄型化及び軽量化が重要である。上記の特許文献１に開示された発明は、携帯無線通信装置の正面方向に放射パターンが向かないようにする点では効果があっても、装置筐体の厚み方向に主アンテナと対向素子の一定値以上の間隔を設ける必要があるため、装置の小型化、薄型化の面で限界がある。
【０００９】
また、上記の特許文献２又は特許文献３に開示された発明は、アンテナ自体の広帯域化の面では効果があっても、携帯無線通信装置に組み込んだ時に放射パターンを最適化して、放射効率が低下しないようにすることはできない。
【００１０】
出願人は、特許文献１乃至特許文献３に開示されたような従来技術では解決できなかった、放射パターンの改善及び装置の小型・薄型化の両立という技術課題を解決することのできる発明を、特願２００２−３６７５４８において、これらの従来技術とは異なる具体的な構成をもって開示した。
【００１１】
そこで、本発明は、これをさらに広帯域化することによって、携帯無線通信装置に組み込んだ時の放射パターンの最適化、装置の小型化・薄型化への適合、及び所要の周波数帯をカバーし得る周波数特性を同時に実現することのできるアンテナ装置及び当該アンテナ装置を用いた携帯無線通信装置を提供することを目的とする。
【００１２】
【課題を解決するための手段】
上記の目的を達成するために、本発明のアンテナ装置は、給電手段が接続され、前記給電手段から給電されたときに発生する駆動電流ベクトルが属する平面において対称軸を中心に略線対称をなすように構成されたダイポールアンテナと、前記平面において、前記対称軸を中心に略線対称をなすように構成されるとともに、前記ダイポールアンテナに対し所定値以下の距離で配設され、前記駆動電流ベクトルによって前記平面に属する第１の誘導電流ベクトルが誘導される導体からなる対向素子とを有し、前記ダイポールアンテナの両端部と前記対向素子の両端部とが互いに離れる方向に折り曲げられてなるアンテナ装置であって、前記対称軸を中心に略線対称をなすように構成されるとともに、前記ダイポールアンテナを挟んで前記対向素子の反対側において前記ダイポールアンテナと所定値以下の距離で配設され、前記駆動電流ベクトルによって第２の誘導電流ベクトルが誘導される導体からなる第１の寄生素子と、前記対称軸を中心に略線対称をなすように構成されるとともに、前記対向素子を挟んで前記ダイポールアンテナの反対側において前記対向素子と所定値以下の距離で配設され、前記第１の誘導電流ベクトルによって第３の誘導電流ベクトルが誘導される導体からなる第２の寄生素子とを備えたことを特徴とする。
【００１３】
また、本発明の携帯無線通信装置は、第１の平面に受話手段が設けられた本体と、前記本体内に配設された給電手段と、前記給電手段に接続され、前記給電手段から給電されたときに前記第１の平面に平行な第２の平面において駆動電流ベクトルが発生するとともに、前記第２の平面において対称軸を中心に略線対称をなすように構成されたダイポールアンテナと、前記第２の平面において、前記対称軸を中心に略線対称をなすように構成されるとともに、前記ダイポールアンテナに対し所定値以下の距離で配設され、前記駆動電流ベクトルによって前記第２の平面に属する第１の誘導電流ベクトルが誘導される導体からなる対向素子とを有し、前記ダイポールアンテナの両端部と前記対向素子の両端部とが互いに離れる方向に折り曲げられてなる携帯無線通信装置であって、前記対称軸を中心に略線対称をなすように構成されるとともに、前記ダイポールアンテナを挟んで前記対向素子の反対側において前記ダイポールアンテナと所定値以下の距離で配設され、前記駆動電流ベクトルによって前記第２の平面に属する第２の誘導電流ベクトルが誘導される導体からなる第１の寄生素子と、前記対称軸を中心に略線対称をなすように構成されるとともに、前記対向素子を挟んで前記ダイポールアンテナの反対側において前記対向素子と所定値以下の距離で配設され、前記第１の誘導電流ベクトルによって前記第２の平面に属する第３の誘導電流ベクトルが誘導される導体からなる第２の寄生素子とを備えたことを特徴とする。
【００１４】
本発明によれば、携帯無線通信装置の所要の周波数特性を備えたアンテナ装置を内蔵して装置の小型化・薄型化に寄与すると共に、正面方向の放射を抑制して放射効率の低下を防ぐことができる。
【００１５】
【発明の実施の形態】
（第１の実施の形態）
以下に、本発明の第１の実施の形態を、図１（ａ）乃至（ｄ）を参照して説明する。図１（ａ）は、本発明の第１の実施の形態に係るアンテナ装置及び携帯無線通信装置の構成を説明する図である。図中、１は携帯無線通信装置の筐体であり、その前後、左右及び上下を、図の左側に示したように定義している。ここで「前」は正面方向（使用者の方向）である。
【００１６】
２はダイポールアンテナで、長さは原則として半波長であり、給電点３が接続されている。この実施の形態では、主に水平偏波で使用されるものと想定し、筐体１の左右方向に取り付けられている。また、４は筐体1に取り付けられた受話器である。
【００１７】
５は、ダイポールアンテナ２に平行に、４分の１波長以下の距離を置いて配設された対向素子である。なお、この発明において「平行」という用語は、厳密に「平行」状態ではなくても、その目的を達して課題の解決に寄与する程度に略「平行」であるといえる場合を含むものである。また、「垂直」、「対称」、「線対称」、「半波長」、「４分の１波長」、「同一平面内」等の用語についても同様である。
【００１８】
６は、ダイポールアンテナ２に平行に、４分の１波長以下の距離を置いて配設された寄生素子（１）であり、ダイポールアンテナ２とは全長が異なっている。また、７は対向素子５に平行に、４分の１波長以下の距離を置いて配設された寄生素子（２）であり、対向素子５よりもやや短く形成されている。また、ダイポールアンテナ２、対向素子５、寄生素子(１)６及び寄生素子(２)７は、いずれも図中に示した対称軸Lを挟んで線対称に構成されており、駆動電流ベクトル及び誘導電流ベクトル（１）乃至誘導電流ベクトル（３）はすべて同一平面内に生じるものとしている。なお、上記の対称軸及び平面は、ダイポールアンテナ等の構成要素の形状又は位置関係を表現するための幾何学的概念であって、本発明を構成する有体物ではない（以下においても同様とする。）。
【００１９】
次に、図１（ｂ）乃至（ｄ）を参照して、本発明の第１の実施の形態に係るアンテナ装置の動作について説明する。図１（ｂ）は当該動作の原理を説明する図で、図中の符号２、３及び５乃至７は図１（ａ）と共通である。ダイポールアンテナ２には給電点３から給電されることによって駆動電流ベクトルが生じ、これに平行に４分の１波長（λ／４）以下の距離を置いて配設された対向素子５には、逆相の誘導電流ベクトル（１）が生じる。
【００２０】
また、同じくダイポールアンテナ２に平行に４分の１波長（λ／４）以下の距離を置いて配設された寄生素子（１）６には、逆相の誘導電流ベクトル（２）が生じ、対向素子５に平行に４分の１波長（λ／４）以下の距離を置いて配設された寄生素子（２）７には駆動電流ベクトルと同相の誘導電流ベクトル（３）が生じる。
【００２１】
ここで、ダイポールアンテナ２の駆動電流ベクトル及び対向素子５の誘導電流ベクトル（１）によって生じる電磁界の放射パターンを筐体１の左側の方向から見ると、図１（ｃ）に示すように「前」−「後」軸を挟んで中央がくびれた（ヌルが形成された）形になる。これは、駆動電流ベクトルと誘導電流ベクトル（１）が互いに逆相であるために、合成された放射パターンは中央付近で相互に減殺されるからである。また、ダイポールアンテナ２及び対向素子５が筐体１の「左」−「右」方向に取り付けられているから水平偏波成分が優勢であり、また対称軸Lを挟んで線対称に構成されているから、筐体１の前側の方向から見た時の放射パターン（図示せず）は左右対称となる。
【００２２】
この場合の給電点３から見たＶＳＷＲは、図１(ｄ)の破線で示すように、ダイポールアンテナ２の長さによって定まる「共振１」なる１の共振点を有する単峰性の周波数特性を示すものとなる。
【００２３】
また、寄生素子(１)６の誘導電流ベクトル（２）及び寄生素子(２)７の誘導電流ベクトル（３）も逆相関系にあるから、これらの電流ベクトルによって形成される電磁界の放射パターンは、図１(ｃ)に示したのと同じ形状になる。しかし周波数特性の点では、寄生素子(１)６をダイポールアンテナ２よりも短く形成しているから、駆動電流ベクトル及び誘導電流ベクトル（１）によって形成される電磁界の共振点よりも高い周波数に「共振２」なる１の共振点を有するものとなる。結果として、放射電磁界全体としての周波数特性は、図１（ｄ）の実線で示すような双峰性を示すものとなり、同図に破線で示した特性に対して実質的に広帯域化される。なお、図１（ｄ）において、実線で示した共振１又は共振２と破線で示した共振点が重なっていないのは、図を見やすくするためである。
【００２４】
本発明の第１の実施の形態によれば、コンパクトに構成されたアンテナ装置を携帯無線通信装置に内蔵して、通常の使用の状態において使用者の方向の放射を抑制した放射パターンを形成し、かつ、周波数軸上に２の共振点を持たせて広帯域化することができる。
【００２５】
（第２の実施の形態）
以下に、本発明の第２の実施の形態を、図２を参照して説明する。図２（ａ）及び（ｂ）は、本発明の第２の実施の形態に係るアンテナ装置及び携帯無線通信装置の構成を説明する図である。図中の符号は図１と共通であるので、その説明を省略する。
【００２６】
第２の実施の形態における図２（ａ）のアンテナ装置の構成が図１（ａ）の構成と異なる点は、ダイポールアンテナ２の両端を含む部分及び対向素子５の両端を含む部分が、お互いに遠ざかる方向へ折り曲げられている点である。なお、寄生素子（１）６はダイポールアンテナ２の対称軸Ｌと交差する部分と平行に配設され、寄生素子（２）７は対向素子５の対称軸Ｌと交差する部分と平行に配設されている。ダイポールアンテナ２、対向素子５、寄生素子（１）６及び寄生素子（２）７がそれぞれ共通の対称軸Lを挟んで線対称に構成され、また各電流ベクトルが同一平面内に生じる点は、図１（ａ）と同じである。
【００２７】
また、図２（ｂ）のアンテナ装置の構成が図２（ａ）の構成と異なる点は、寄生素子（１）６及び寄生素子（２）７が、それぞれ、ダイポールアンテナ２及び対向素子５の折り曲げられた両端の部分と平行に配設された点である。
【００２８】
次に、図２（ａ）及び（ｂ）を参照して、本発明の第２の実施の形態に係るアンテナ装置の動作について説明する。図２（ａ）及び（ｂ）においては、ダイポールアンテナ２及び対向素子５の両端を含む部分が折り曲げられ、「上」−「下」軸に平行に向いている。したがって、これらの両端を含む部分に生じる駆動電流ベクトル及び誘導電流ベクトルによって発生する放射電磁界（図１（ｄ）の「共振１」に相当）は、垂直偏波成分が優勢となる。両電流ベクトルは互いに逆相であるから、垂直偏波成分についても正面方向にはヌルが形成される。
【００２９】
これに対して、寄生素子（１）６及び寄生素子（２）７に生じる誘導電流ベクトルによって形成される放射電磁界は、周波数軸上では図１（ｄ）の「共振２」に相当し、図２（ａ）の場合は主に水平偏波成分から構成され、図２（ｂ）の場合は主に垂直偏波成分から構成されることとなる。
【００３０】
本発明の第２の実施の形態によれば、水平偏波成分だけでなく垂直偏波成分についても正面方向に放射電磁界のヌルを形成すると共に、周波数軸上の共振点の双峰性を実現するという、付加的な効果が得られる。
【００３１】
（第３の実施の形態）
以下に、本発明の第３の実施の形態を、図３を参照して説明する。図３は、本発明の第３の実施の形態に係るアンテナ装置の構成を説明する図である。なお、携帯無線通信装置への取付けについては、図中に図１及び図２と意味を共通にする座標軸で示したように、これらの図と共通であるので図示を省略した。即ち、図中で上に当る方向が、携帯無線通信装置の正面方向である。図中の符号２、３及び５乃至７は図１と共通である。なお、ダイポールアンテナ２、対向素子５、寄生素子（１）６及び寄生素子（２）７は、例えば図示しない誘電体基板上に一定の幅を持ったパターンとして形成されたものである。
【００３２】
図３の構成と図２（ａ）の構成との相違は、寄生素子（１）６及び寄生素子（２）７も、その両端を含む部分がお互いに遠ざかる方向へ折り曲げられている点であり、その他の点は、各構成要素が対称軸Ｌを挟んで線対称に構成されている点を含め、図２（ａ）と同じである。このような構成をとることによって、ダイポールアンテナ２及び対向素子５によって形成される図１（ｄ）の「共振１」に相当する放射電磁界だけでなく、寄生素子（１）６及び寄生素子（２）７によって形成される図１（ｄ）の「共振２」に相当する放射電磁界も、主として垂直偏波成分に対応するものとなる。
【００３３】
本発明の第３の実施の形態によれば、主に垂直偏波成分に対して、周波数軸上の共振点の双峰性を実現することができる。
【００３４】
（第４の実施の形態）
以下に、本発明の第４の実施の形態を、図４を参照して説明する。図４（ａ）及び（ｂ）は、本発明の第４の実施の形態に係るアンテナ装置の構成を説明する図である。図中の符号２、３及び５乃至７はすべて図３と共通である。しかし、図３においてはダイポールアンテナ２、対向素子５、寄生素子（１）６及び寄生素子（２）７のすべてがほぼ同一平面内にあり、これらに生じる電流ベクトルがその同一平面内にあったが、図４（ａ）及び（ｂ）においては、ダイポールアンテナ２及び対向素子５の属する平面（ここでは、下平面という。）と、寄生素子（１）６及び寄生素子（２）７の属する平面（ここでは、上平面という。）とが同一ではなく、「前」−「後」軸の方向に４分の１波長以下の距離を置いて平行に位置する関係にある。
【００３５】
図４（ａ）においては、寄生素子（１）６はダイポールアンテナ２の対称軸Ｌと交差する部分と平行に配設され、寄生素子（２）７は対向素子５の対称軸Ｌと交差する部分と平行に配設される。また、寄生素子（１）６及び寄生素子（２）７は共に、上平面に属し対称軸Ｌに平行な対称軸Ｍを挟んで線対称に構成される。なお、対称軸Ｌ及び対称軸Ｍは、それらが形成する平面が上平面及び下平面に直交する関係にある。
【００３６】
また、図４（ｂ）においては、図４（ａ）とは異なり、寄生素子（１）６及び寄生素子（２）７が、それぞれ、ダイポールアンテナ２及び対向素子５の折り曲げられた両端の部分と平行に配設されると共に、対称軸Ｍを挟んで線対称の関係にある。その他の点は、図４（ａ）と同じである。
【００３７】
図４（ａ）及び（ｂ）の構成に係るアンテナ装置の動作は、それぞれ図２（ａ）及び（ｂ）に示したものとほとんど同様である。すなわち、図４（ａ）及び（ｂ）の構成ともに正面方向にヌルを有する放射パターンが形成されると共に、図４（ａ）の場合は水平偏波成分について、図４（ｂ）の場合は垂直偏波成分について、それぞれ共振点の双峰性が実現される。
【００３８】
本発明の第４の実施の形態によれば、実装スペースの制約上、複数のアンテナ素子を２階建て構造で実装しなければならないような場合に、きわめて有効な解決手段が得られる。なお、ダイポールアンテナ２及び対向素子５によって形成される共振点が送信周波数側に対応するような場合に、これらを下平面側に配設して前面方向から遠ざけることにより、放射効率の低下をより効果的に抑えることができる。
【００３９】
（第５の実施の形態）
以下に、本発明の第５の実施の形態を、図５を参照して説明する。図５は、本発明の第５の実施の形態に係るアンテナ装置の構成を説明する図である。図中の符号２、３及び５乃至７はすべて図４（ａ）と共通である。
【００４０】
図５の構成と図４（ａ）の構成との相違は、寄生素子（１）６及び寄生素子（２）７も、その両端を含む部分がお互いに遠ざかる方向へ折り曲げられている点であり、その他の点は、ダイポールアンテナ２及び対向素子５が対称軸Ｌを挟んで線対称に構成され、かつ、寄生素子（１）６及び寄生素子（２）７が対称軸Ｍを挟んで線対称に構成されている点を含め、図４（ａ）と同じである。このような構成をとることによって、ダイポールアンテナ２及び対向素子５によって形成される図１（ｄ）の「共振１」に相当する放射電磁界だけでなく、寄生素子（１）６及び寄生素子（２）７によって形成される図１（ｄ）の「共振２」に相当する放射電磁界も、主に垂直偏波成分に対応するものとなる。
【００４１】
本発明の第５の実施の形態によれば、第４の実施の形態における効果に加えて、水平偏波成分及び垂直偏波成分の両方に対して、周波数軸上の共振点の双峰性を実現するという、付加的な効果が得られる。
【００４２】
（第６の実施の形態）
以下に、本発明の第６の実施の形態を、図６（ａ）及び（ｂ）を参照して説明する。図６（ａ）及び（ｂ）は、本発明の第６の実施の形態に係るアンテナ装置の構成を説明する図である。図中の符号２、３及び５乃至７はすべて図３と共通である。
【００４３】
図６（ａ）に示した構成と図３に示した構成との相違は、共通の平面に一定の幅を持って属するダイポールアンテナ２、対向素子５、寄生素子（１）６及び寄生素子（２）７のそれぞれ両端を含む部分が、互いに相手と遠ざかる方向へ（すなわち、「上」又は「下」の方向へ）折り曲げられると同時に、「左」−「右」軸に垂直になるように折り曲げられた点である。
【００４４】
このようにすれば、各素子の両端を含む折り曲げられた部分は、「前」の方向から導体の厚み相当の幅が見えるだけになるから、図３に示した構成に比べ、例えば表示器等の有効実装面積を拡大することができる。アンテナ装置としての特性は、図３に示したものとほとんど変らない。
【００４５】
図６（ｂ）は、各素子の折り曲げられた部分だけではなく、対称軸Ｌと交差する部分も「前」−「後」軸方向に幅を有するように構成したものである。この場合も、図３に示したものと同等のアンテナ特性を保ちつつ、図６（ａ）の場合よりもさらに表示器等の有効実装面積を拡大することができる。
【００４６】
本発明の第６の実施の形態によれば、第３の実施の形態により得られる効果に加えて、携帯無線通信装置の他の構成部品等の有効実装面積を拡大することができるという、付加的な効果が得られる。
【００４７】
（第７の実施の形態）
以下に、本発明の第７の実施の形態を、図７を参照して説明する。図７は、本発明の第７の実施の形態に係るアンテナ装置の構成を説明する図である。図中の符号２、３及び５乃至７は、すべて図４（ａ）と共通であるが、寄生素子（１）６は図４（ａ）の場合と異なり、対称軸Ｌに垂直な面内で「前」−「後」軸の方向に平行な対称軸Ｍ１を挟んで線対称に構成されている。また、寄生素子（２）７は、対称軸Ｌに垂直な別の面内で「前」−「後」軸の方向に平行な対称軸Ｍ２を挟んで線対称に構成されている。
【００４８】
この構成も、第６の実施の形態と同様に、「前」−「後」軸方向（携帯無線通信装置の筐体の厚み方向）をアンテナ装置の実装に有効活用するものである。得られるアンテナ特性は、図２（ａ）又は図４（ａ）の構成と同等である。
【００４９】
本発明の第７の実施の形態によれば、携帯無線通信装置の筐体１の厚み方向をアンテナ装置の実装に有効活用することができるという、付加的な効果が得られる。
【００５０】
（第８の実施の形態）
以下に、本発明の第８の実施の形態を、図８乃至図１１を参照して説明する。図８は、本発明の第３の実施の形態に係るアンテナ装置の構成を説明する図である。図中の符号２、３及び５乃至７は図３と共通であるが、図８においては、ダイポールアンテナ２及び対向素子５が対称軸Lを挟んで線対称の関係にある２個所の位置で短絡部８及び９により短絡されている。このように、ダイポールアンテナ２及び対向素子５の間を短絡することにより、アンテナ装置全体としてのインピーダンス整合を改善することができる。
【００５１】
図９（ａ）は、ダイポールアンテナ２及び対向素子５を、図８に示すように短絡部８及び９により相互に短絡し、かつ、図６（ａ）に示すようにその両端を含む部分を「前」−「後」軸に沿うようにして折り曲げ、さらに「上」−「下」軸に垂直な面内で折り返し部２１ａ、２１ｂ、５１ａ及び５１ｂを設けるようにして構成した場合の斜視図である。なお、メッシュ状に表わされた１０は、筐体１に内蔵する基板であリ、その他の構成は図８と共通である。寄生素子６及び７の図示は省略している。
【００５２】
このような構成により、より狭隘なスペースにおいてダイポールアンテナ２及び対向素子５の所要の線路長を確保することができるので、携帯無線通信装置の小型化に寄与することができる。
【００５３】
図９（ｂ）は、図９（ａ）の構成において、短絡部８及び９を「左」−「右」軸に垂直ね面内で折り返して線路長を拡張し、より広帯域化を図った場合を示す図である。
【００５４】
図１０は、図８に示したアンテナ装置を筐体折畳み形携帯無線通信装置に実装した状態において周波数特性を評価したものである。図１０（ａ）はシミュレーション評価、図１０（ｂ）は実測評価の結果をそれぞれ示している。図中の「ＯＰＥＮ」は筐体１を開いた状態、「ＣＬＯＳＥ」は筐体１を閉じた状態にそれぞれ対応する。これらの図に示すように、２個所の共振点を得ることができる。また、筐体１の開閉による影響をほとんど受けないことが明らかである。
【００５５】
図１１は、同じ構成で放射パターン特性をシミュレーション評価したものである。図１１（Ａ１）乃至（Ａ３）は、図１０における第１の共振点である１９２０ＭＨｚで、同図（Ｂ１）乃至（Ｂ３）は第２の共振点である２１７０ＭＨｚでそれぞれ評価している。ただしこの例では、垂直偏波が優勢となるように設計されたアンテナを評価対象とした。これらの図中、特に（Ａ１）及び（Ｂ１）の図に示されているように、「前」の方向に放射パターンのヌルが形成されているから、人体の影響による放射効率の低下を避けることができる。
【００５６】
なお、以上の本発明の実施の形態１乃至８においては、対向素子５に別の給電点を接続して、ダイポールアンテナ２と逆相で駆動するように構成することも可能である。
【００５７】
【発明の効果】
本発明によれば、携帯無線通信装置への実装に適したコンパクトなアンテナ構成により、前方への電磁界放射を抑えて放射効率の低下を防ぐと同時に、送信及び受信周波数帯をカバーできるように広帯域化することができる。
【図面の簡単な説明】
【図１】（ａ）本発明の第１の実施の形態に係るアンテナ装置及び携帯無線通信装置の構成を説明する図。（ｂ）本発明の第１の実施の形態に係るアンテナ装置の原理を説明する図。（ｃ）本発明の第１の実施の形態に係るアンテナ装置の放射パターン特性を説明する図。（ｄ）本発明の第１の実施の形態に係るアンテナ装置の周波数特性を説明する図。
【図２】本発明の第２の実施の形態に係るアンテナ装置及び携帯無線通信装置の構成を説明する図。
【図３】本発明の第３の実施の形態に係るアンテナ装置の構成を説明する図。
【図４】本発明の第４の実施の形態に係るアンテナ装置の構成を説明する図。
【図５】本発明の第５の実施の形態に係るアンテナ装置の構成を説明する図。
【図６】本発明の第６の実施の形態に係るアンテナ装置の構成を説明する図。
【図７】本発明の第７の実施の形態に係るアンテナ装置の構成を説明する図。
【図８】本発明の第８の実施の形態に係るアンテナ装置の構成を説明する図。
【図９】本発明の第８の実施の形態に係るアンテナ装置の構成を説明する斜視図。
【図１０】本発明の第８の実施の形態に係るアンテナ装置の周波数特性を示す図。
【図１１】本発明の第８の実施の形態に係るアンテナ装置の放射パターン特性を示す図。
【符号の説明】
１筐体
２ダイポールアンテナ
２１ａ、２１ｂダイポールアンテナの両端の折り返し部
３給電点
４受話器
５対向素子
５１ａ、５１ｂ対向素子の両端の折り返し部
６寄生素子（１）
７寄生素子（２）
８、９短絡部
１０基板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an antenna device and a portable radio communication device, and more particularly to an antenna device that can be built in a main body of the portable radio communication device and the portable radio communication device.
[0002]
[Prior art]
Antennas for portable wireless communication devices are shifting from types similar to whip-type antennas that are mounted so that they can be pulled out of the housing during use, which has been the mainstream until now, to built-in types. By using the built-in antenna, handling at the time of use and storage is much easier than when using a conventional type antenna, and there are advantages such as increased flexibility in housing design. Among them, the advantage that the casing can be made thinner is great.
[0003]
However, a plate-like inverted F antenna that has been generally used as a built-in antenna or a dipole antenna with a simple configuration has a radiation pattern formed in the front direction (direction of the user) of the portable radio communication device. There has been a problem in that radiation efficiency is lowered due to mismatch loss and dielectric loss. In order to improve such a problem, an invention has been made in which a non-feeding counter element is combined with a main antenna constituted by a dipole antenna (see, for example, Patent Document 1). In the invention disclosed in Patent Document 1, the main antenna is arranged in parallel to the surface to which the receiver is attached, and the opposing element is arranged in parallel to the main antenna at a distance of a certain value or more in a direction perpendicular to the surface. It is to do.
[0004]
On the other hand, widening the frequency characteristics is also an important issue for the built-in antenna. In this respect, a method of configuring an antenna by arranging a parasitic element whose resonance frequency is shifted close to the main antenna has been known in the past, and an invention that has been miniaturized so that it can be applied to a portable radio communication device or the like. (For example, see Patent Document 2 or Patent Document 3). The invention disclosed in Patent Document 2 uses a two-surface electrode as a main antenna and a parasitic element with a slit provided obliquely on the main surface of a rectangular parallelepiped made of a dielectric, thereby reducing the size and wideband. It aims to make it easier. In addition, the invention disclosed in Patent Document 3 includes a parasitic main element having one end open on the surface of the dielectric, the other end feeding, a linear main antenna having a quarter-wavelength, and a line length of 40% or less. The antenna is configured by providing a small size and a wide band.
[0005]
[Patent Document 1]
JP 2002-9534 A (2nd, 6th, 7th, 11th, 12th pages, FIG. 66)
[0006]
[Patent Document 2]
Japanese Patent No. 3351363 (second and third pages, FIG. 1)
[0007]
[Patent Document 3]
JP 2002-344222 A (second page, FIG. 1)
[0008]
[Problems to be solved by the invention]
In a portable wireless communication device, among various information devices or communication devices, it is particularly important to reduce the size, thickness, and weight. Although the invention disclosed in Patent Document 1 is effective in preventing the radiation pattern from being directed in the front direction of the portable wireless communication device, the main antenna and the opposing element are fixed in the thickness direction of the device housing. Since it is necessary to provide an interval larger than the value, there is a limit in reducing the size and thickness of the apparatus.
[0009]
Further, although the invention disclosed in Patent Document 2 or Patent Document 3 described above is effective in terms of widening the antenna itself, the radiation pattern is optimized when incorporated in a portable wireless communication device, and the radiation efficiency is improved. It cannot be prevented from deteriorating.
[0010]
The applicant can solve the technical problem of improving the radiation pattern and reducing the size and thickness of the apparatus, which cannot be solved by the conventional techniques disclosed in Patent Documents 1 to 3, Japanese Patent Application No. 2002-367548 discloses a specific configuration different from those of the prior art.
[0011]
Therefore, the present invention can further cover the frequency band by optimizing the radiation pattern when incorporated in a portable wireless communication device, adapting to the downsizing / thinning of the device, and the required frequency band. It is an object of the present invention to provide an antenna device capable of realizing frequency characteristics at the same time and a portable wireless communication device using the antenna device.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the antenna device of the present invention provides means Connected to the power supply means When power is supplied from appear Axis of symmetry in the plane to which the drive current vector belongs Abbreviated in the center Line symmetry To make A dipole antenna configured in The plane is configured to be substantially line symmetric about the axis of symmetry, and is disposed at a distance of a predetermined value or less with respect to the dipole antenna, A first induced current vector belonging to the plane is induced by the drive current vector. An antenna device, wherein both ends of the dipole antenna and both ends of the counter element are bent away from each other, and are substantially line symmetric about the axis of symmetry. And is disposed at a distance of a predetermined value or less from the dipole antenna on the opposite side of the opposing element across the dipole antenna, A second induced current vector is induced by the drive current vector Made of conductor A first parasitic element; It is configured to be substantially line symmetric about the symmetry axis, and is disposed at a distance of a predetermined value or less from the opposing element on the opposite side of the dipole antenna across the opposing element, A first induced current vector induces a third induced current vector Made of conductor And a second parasitic element.
[0013]
The portable wireless communication device of the present invention is A main body provided with receiving means on a first plane, a power supply means disposed in the main body, and connected to the power supply means and parallel to the first plane when power is supplied from the power supply means A driving current vector is generated in the second plane, and the dipole antenna is configured to be substantially line symmetric about the symmetry axis in the second plane, and the symmetry axis is centered in the second plane. The first induced current vector belonging to the second plane is induced by the drive current vector, and is arranged at a distance of a predetermined value or less with respect to the dipole antenna. A portable wireless communication device comprising: a counter element made of a conductor, wherein both end portions of the dipole antenna and both end portions of the counter element are bent away from each other; It is configured to be substantially line symmetric about the axis of symmetry, and is disposed at a distance equal to or less than a predetermined value from the dipole antenna on the opposite side of the opposing element across the dipole antenna. A first parasitic element made of a conductor from which a second induced current vector belonging to the second plane is induced is configured to be substantially line symmetric about the symmetry axis, and sandwiching the counter element A second conductor is disposed on the opposite side of the dipole antenna at a distance equal to or less than a predetermined value from the opposing element, and a third induced current vector belonging to the second plane is induced by the first induced current vector. With two parasitic elements It is characterized by.
[0014]
According to the present invention, an antenna device having a required frequency characteristic of a portable wireless communication device is incorporated to contribute to the downsizing and thinning of the device, and radiation in the front direction is suppressed to prevent a reduction in radiation efficiency. be able to.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
A first embodiment of the present invention will be described below with reference to FIGS. 1 (a) to 1 (d). FIG. 1A is a diagram for explaining the configuration of an antenna device and a portable radio communication device according to the first embodiment of the present invention. In the figure, reference numeral 1 denotes a casing of the portable wireless communication device, and its front and rear, left and right, and top and bottom are defined as shown on the left side of the figure. Here, “front” is the front direction (the direction of the user).
[0016]
A dipole antenna 2 has a length of half a wavelength in principle, and a feed point 3 is connected thereto. In this embodiment, it is assumed that it is mainly used in horizontal polarization, and is attached in the left-right direction of the housing 1. Reference numeral 4 denotes a receiver attached to the housing 1.
[0017]
Reference numeral 5 denotes a counter element disposed parallel to the dipole antenna 2 with a distance of a quarter wavelength or less. In the present invention, the term “parallel” includes a case where it can be said that it is substantially “parallel” to the extent that it achieves its purpose and contributes to the solution of the problem even if it is not strictly “parallel”. The same applies to terms such as “vertical”, “symmetry”, “line symmetry”, “half wavelength”, “quarter wavelength”, and “in the same plane”.
[0018]
Reference numeral 6 denotes a parasitic element (1) arranged in parallel with the dipole antenna 2 at a distance of a quarter wavelength or less, and the total length is different from that of the dipole antenna 2. Reference numeral 7 denotes a parasitic element (2) disposed in parallel with the opposing element 5 at a distance of a quarter wavelength or less, and is formed slightly shorter than the opposing element 5. The dipole antenna 2, the counter element 5, the parasitic element (1) 6, and the parasitic element (2) 7 are all configured to be line-symmetric with respect to the symmetry axis L shown in the figure, and the drive current vector and The induced current vectors (1) to (3) are all generated in the same plane. Note that the symmetry axis and plane described above are geometric concepts for expressing the shape or positional relationship of components such as a dipole antenna, and are not tangible objects that constitute the present invention (the same applies hereinafter). ).
[0019]
Next, the operation of the antenna device according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1B is a diagram for explaining the principle of the operation, and reference numerals 2, 3 and 5 to 7 in the figure are the same as those in FIG. A driving current vector is generated in the dipole antenna 2 by being fed from the feeding point 3, and the opposing element 5 disposed at a distance equal to or less than a quarter wavelength (λ / 4) in parallel to the dipole antenna 2 includes: A negative-phase induced current vector (1) is generated.
[0020]
Similarly, the parasitic element (1) 6 disposed in parallel with the dipole antenna 2 at a distance equal to or less than a quarter wavelength (λ / 4) has an inductive current vector (2) of a reverse phase, Inductive current vector (3) having the same phase as the drive current vector is generated in parasitic element (2) 7 arranged at a distance equal to or smaller than a quarter wavelength (λ / 4) in parallel with counter element 5.
[0021]
Here, when the radiation pattern of the electromagnetic field generated by the driving current vector of the dipole antenna 2 and the induced current vector (1) of the counter element 5 is viewed from the left side of the housing 1, as shown in FIG. The center is constricted (null is formed) across the front-back axis. This is because the combined radiation pattern is mutually attenuated near the center because the driving current vector and the induced current vector (1) are out of phase with each other. In addition, since the dipole antenna 2 and the counter element 5 are attached in the “left”-“right” direction of the housing 1, the horizontal polarization component is dominant, and the dipole antenna 2 and the counter element 5 are configured to be line symmetrical with respect to the symmetry axis L. Therefore, the radiation pattern (not shown) when viewed from the front side of the housing 1 is bilaterally symmetric.
[0022]
The VSWR seen from the feeding point 3 in this case has a single-peak frequency characteristic having one resonance point “resonance 1” determined by the length of the dipole antenna 2 as shown by a broken line in FIG. It will be shown.
[0023]
In addition, since the induced current vector (2) of the parasitic element (1) 6 and the induced current vector (3) of the parasitic element (2) 7 are also in an inverse correlation system, the radiation pattern of the electromagnetic field formed by these current vectors Is the same shape as shown in FIG. However, in terms of frequency characteristics, since the parasitic element (1) 6 is formed shorter than the dipole antenna 2, the frequency is higher than the resonance point of the electromagnetic field formed by the drive current vector and the induced current vector (1). It has one resonance point “resonance 2”. As a result, the frequency characteristics of the radiated electromagnetic field as a whole show the bimodality as shown by the solid line in FIG. 1D, and the bandwidth is substantially increased with respect to the characteristics shown by the broken line in FIG. . In FIG. 1D, the resonance 1 or resonance 2 indicated by the solid line and the resonance point indicated by the broken line do not overlap with each other in order to make the drawing easier to see.
[0024]
According to the first embodiment of the present invention, a compactly configured antenna device is built in a portable wireless communication device to form a radiation pattern that suppresses radiation in the direction of the user in a normal use state. In addition, it is possible to provide a wide band by providing two resonance points on the frequency axis.
[0025]
(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIG. FIGS. 2A and 2B are diagrams illustrating the configurations of an antenna device and a portable radio communication device according to the second embodiment of the present invention. The reference numerals in the figure are the same as those in FIG.
[0026]
The configuration of the antenna device of FIG. 2A in the second embodiment is different from the configuration of FIG. 1A in that the portion including both ends of the dipole antenna 2 and the portion including both ends of the counter element 5 are mutually connected. It is the point which is bent in the direction away from. Parasitic element (1) 6 is arranged in parallel with a portion intersecting with symmetry axis L of dipole antenna 2, and parasitic element (2) 7 is arranged in parallel with a portion intersecting with symmetry axis L of opposing element 5. Has been. The dipole antenna 2, the opposing element 5, the parasitic element (1) 6 and the parasitic element (2) 7 are configured to be line symmetric with respect to the common symmetry axis L, and each current vector is generated in the same plane. This is the same as FIG.
[0027]
Further, the configuration of the antenna device of FIG. 2B is different from the configuration of FIG. 2A in that the parasitic element (1) 6 and the parasitic element (2) 7 are the dipole antenna 2 and the counter element 5 respectively. It is the point arrange | positioned in parallel with the part of the both ends bent.
[0028]
Next, operations of the antenna device according to the second embodiment of the present invention will be described with reference to FIGS. In FIGS. 2A and 2B, the portions including both ends of the dipole antenna 2 and the opposing element 5 are bent and faced parallel to the “upper”-“lower” axis. Therefore, in the radiated electromagnetic field (corresponding to “resonance 1” in FIG. 1D) generated by the drive current vector and the induced current vector generated in the portion including both ends, the vertical polarization component is dominant. Since both current vectors are opposite in phase, a null is formed in the front direction for the vertically polarized component.
[0029]
On the other hand, the radiated electromagnetic field formed by the induced current vector generated in the parasitic element (1) 6 and the parasitic element (2) 7 corresponds to “resonance 2” in FIG. In the case of FIG. 2A, it is mainly composed of horizontal polarization components, and in the case of FIG. 2B, it is mainly composed of vertical polarization components.
[0030]
According to the second embodiment of the present invention, the null of the radiated electromagnetic field is formed in the front direction not only for the horizontal polarization component but also for the vertical polarization component, and the bimodality of the resonance point on the frequency axis is increased. An additional effect of realizing is obtained.
[0031]
(Third embodiment)
Below, the 3rd Embodiment of this invention is described with reference to FIG. FIG. 3 is a diagram for explaining the configuration of the antenna device according to the third embodiment of the present invention. In addition, about attachment to a portable radio | wireless communication apparatus, as shown in the coordinate axis which has a common meaning with FIG.1 and FIG.2 in the figure, since it was common to these figures, illustration was abbreviate | omitted. That is, the upward direction in the figure is the front direction of the portable wireless communication device. Reference numerals 2, 3 and 5 to 7 in the figure are the same as those in FIG. The dipole antenna 2, the counter element 5, the parasitic element (1) 6, and the parasitic element (2) 7 are formed as a pattern having a certain width on a dielectric substrate (not shown), for example.
[0032]
The difference between the configuration of FIG. 3 and the configuration of FIG. 2 (a) is that the parasitic element (1) 6 and the parasitic element (2) 7 are also bent in a direction in which the portions including both ends thereof are away from each other. The other points are the same as those in FIG. 2A, including the point that each component is configured to be line symmetrical with respect to the symmetry axis L. By adopting such a configuration, not only the radiated electromagnetic field corresponding to “resonance 1” in FIG. 1D formed by the dipole antenna 2 and the counter element 5, but also the parasitic element (1) 6 and the parasitic element ( 2) The radiated electromagnetic field corresponding to “resonance 2” in FIG. 1D formed by 7 also mainly corresponds to the vertical polarization component.
[0033]
According to the third embodiment of the present invention, the bimodality of the resonance point on the frequency axis can be realized mainly for the vertical polarization component.
[0034]
(Fourth embodiment)
Below, the 4th Embodiment of this invention is described with reference to FIG. FIGS. 4A and 4B are diagrams illustrating the configuration of an antenna device according to the fourth embodiment of the present invention. Reference numerals 2, 3 and 5 to 7 in the figure are all the same as those in FIG. However, in FIG. 3, the dipole antenna 2, the opposing element 5, the parasitic element (1) 6, and the parasitic element (2) 7 are all in the same plane, and the current vectors generated in these are in the same plane. However, in FIGS. 4A and 4B, the plane to which the dipole antenna 2 and the counter element 5 belong (herein referred to as the lower plane), the parasitic element (1) 6 and the parasitic element (2) 7 belong. The plane (here, referred to as the upper plane) is not the same, and is in a relationship of being parallel with a distance of a quarter wavelength or less in the direction of the “front”-“back” axis.
[0035]
In FIG. 4A, the parasitic element (1) 6 is arranged in parallel with a portion intersecting with the symmetry axis L of the dipole antenna 2 and the parasitic element (2) 7 intersects with the symmetry axis L of the counter element 5. Arranged parallel to the part. The parasitic element (1) 6 and the parasitic element (2) 7 are both configured to be line-symmetric with respect to the symmetry axis M belonging to the upper plane and parallel to the symmetry axis L. Note that the symmetry axis L and the symmetry axis M have a relationship in which the plane formed by them is perpendicular to the upper plane and the lower plane.
[0036]
4 (b), unlike FIG. 4 (a), the parasitic element (1) 6 and the parasitic element (2) 7 are the bent portions of the dipole antenna 2 and the opposing element 5, respectively. And a line-symmetric relationship with respect to the symmetry axis M. The other points are the same as in FIG.
[0037]
The operation of the antenna device according to the configuration of FIGS. 4A and 4B is almost the same as that shown in FIGS. 2A and 2B, respectively. That is, in the configurations of FIGS. 4A and 4B, a radiation pattern having a null in the front direction is formed, and in the case of FIG. 4A, the horizontal polarization component is illustrated, and in the case of FIG. For the vertically polarized component, bimodality at the resonance point is realized.
[0038]
According to the fourth embodiment of the present invention, a very effective solution can be obtained when a plurality of antenna elements must be mounted in a two-story structure due to restrictions on mounting space. When the resonance point formed by the dipole antenna 2 and the opposing element 5 corresponds to the transmission frequency side, disposing these on the lower plane side away from the front direction further reduces the radiation efficiency. It can be effectively suppressed.
[0039]
(Fifth embodiment)
Hereinafter, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a diagram for explaining the configuration of an antenna apparatus according to the fifth embodiment of the present invention. Reference numerals 2, 3 and 5 to 7 in the figure are all the same as those in FIG.
[0040]
The difference between the configuration of FIG. 5 and the configuration of FIG. 4A is that the parasitic element (1) 6 and the parasitic element (2) 7 are also bent in a direction in which the portions including both ends are away from each other. The other points are that the dipole antenna 2 and the opposing element 5 are line-symmetric with respect to the symmetry axis L, and the parasitic element (1) 6 and the parasitic element (2) 7 are line-symmetric with respect to the symmetry axis M. 4 is the same as FIG. By adopting such a configuration, not only the radiated electromagnetic field corresponding to “resonance 1” in FIG. 1D formed by the dipole antenna 2 and the counter element 5, but also the parasitic element (1) 6 and the parasitic element ( 2) The radiated electromagnetic field corresponding to “resonance 2” in FIG. 1 (d) formed by 7 also mainly corresponds to the vertical polarization component.
[0041]
According to the fifth embodiment of the present invention, in addition to the effects of the fourth embodiment, the bimodality of the resonance point on the frequency axis with respect to both the horizontal polarization component and the vertical polarization component. An additional effect of realizing is obtained.
[0042]
(Sixth embodiment)
A sixth embodiment of the present invention will be described below with reference to FIGS. 6 (a) and 6 (b). FIGS. 6A and 6B are diagrams illustrating the configuration of the antenna device according to the sixth embodiment of the present invention. Reference numerals 2, 3 and 5 to 7 in the figure are all the same as those in FIG.
[0043]
The difference between the configuration shown in FIG. 6A and the configuration shown in FIG. 3 is that the dipole antenna 2, the opposing element 5, the parasitic element (1) 6, and the parasitic element ( 2) The portions including both ends of 7 are bent away from each other (ie, in the “up” or “down” direction), and at the same time, perpendicular to the “left”-“right” axis. It is a bent point.
[0044]
In this way, the folded portion including both ends of each element can only see the width corresponding to the thickness of the conductor from the “front” direction, and therefore, for example, a display or the like compared to the configuration shown in FIG. The effective mounting area can be expanded. The characteristics as an antenna device are almost the same as those shown in FIG.
[0045]
In FIG. 6B, not only the bent portion of each element but also the portion intersecting with the symmetry axis L has a width in the “front”-“rear” axial direction. In this case as well, the effective mounting area of the display device or the like can be further increased as compared with the case of FIG. 6A while maintaining the antenna characteristics equivalent to those shown in FIG.
[0046]
According to the sixth embodiment of the present invention, in addition to the effect obtained by the third embodiment, the effective mounting area of other components of the portable wireless communication device can be expanded. Effects can be obtained.
[0047]
(Seventh embodiment)
Hereinafter, a seventh embodiment of the present invention will be described with reference to FIG. FIG. 7 is a diagram for explaining the configuration of the antenna device according to the seventh embodiment of the present invention. Reference numerals 2, 3 and 5 to 7 in the figure are all the same as those in FIG. 4A, but the parasitic element (1) 6 is in a plane perpendicular to the symmetry axis L, unlike the case of FIG. The line is symmetrical with respect to the axis of symmetry M1 parallel to the directions of the “front” and “rear” axes. Further, the parasitic element (2) 7 is configured to be line-symmetrical with a symmetry axis M2 parallel to the direction of the “front”-“back” axis in another plane perpendicular to the symmetry axis L.
[0048]
As in the sixth embodiment, this configuration also effectively utilizes the “front”-“rear” axial direction (the thickness direction of the casing of the portable wireless communication device) for mounting the antenna device. The obtained antenna characteristics are equivalent to the configuration of FIG. 2 (a) or FIG. 4 (a).
[0049]
According to the seventh embodiment of the present invention, there is an additional effect that the thickness direction of the casing 1 of the portable wireless communication device can be effectively used for mounting the antenna device.
[0050]
(Eighth embodiment)
Hereinafter, an eighth embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a diagram for explaining a configuration of an antenna device according to the third embodiment of the present invention. Reference numerals 2, 3 and 5 to 7 in the figure are the same as those in FIG. 3, but in FIG. 8, the dipole antenna 2 and the opposing element 5 are in two positions that are in a line-symmetric relationship with the symmetry axis L in between. Short-circuited by the short-circuit portions 8 and 9. Thus, the impedance matching as the whole antenna apparatus can be improved by short-circuiting between the dipole antenna 2 and the opposing element 5.
[0051]
FIG. 9A shows a portion in which the dipole antenna 2 and the counter element 5 are short-circuited to each other by the short-circuit portions 8 and 9 as shown in FIG. 8 and the both ends are included as shown in FIG. 6A. A perspective view in the case of being bent along the "front"-"rear" axis and further provided with folded portions 21a, 21b, 51a and 51b in a plane perpendicular to the "upper"-"lower" axis. It is. Note that reference numeral 10 shown in a mesh form denotes a substrate built in the housing 1, and other configurations are the same as those in FIG. The parasitic elements 6 and 7 are not shown.
[0052]
With such a configuration, the required line lengths of the dipole antenna 2 and the counter element 5 can be ensured in a narrower space, which can contribute to downsizing of the portable radio communication device.
[0053]
FIG. 9B expands the line length by folding the short-circuit portions 8 and 9 in the plane perpendicular to the “left”-“right” axis in the configuration of FIG. It is a figure which shows a case.
[0054]
FIG. 10 shows an evaluation of frequency characteristics in a state where the antenna device shown in FIG. 8 is mounted on a case folding portable wireless communication device. FIG. 10A shows the result of the simulation evaluation, and FIG. 10B shows the result of the actual measurement evaluation. In the figure, “OPEN” corresponds to a state in which the housing 1 is opened, and “CLOSE” corresponds to a state in which the housing 1 is closed. As shown in these figures, two resonance points can be obtained. In addition, it is clear that the housing 1 is hardly affected by opening and closing.
[0055]
FIG. 11 shows a simulation evaluation of the radiation pattern characteristics with the same configuration. 11A1 to 11A3 are evaluated at 1920 MHz, which is the first resonance point in FIG. 10, and FIGS. 11B1 to B3 are evaluated at 2170 MHz, which is the second resonance point. However, in this example, an antenna designed so that the vertical polarization is dominant is used as an evaluation target. In these figures, especially as shown in the figures (A1) and (B1), a null of the radiation pattern is formed in the “front” direction, so a decrease in radiation efficiency due to the influence of the human body is avoided. be able to.
[0056]
In the first to eighth embodiments of the present invention described above, another feeding point may be connected to the counter element 5 so as to be driven in a phase opposite to that of the dipole antenna 2.
[0057]
【The invention's effect】
According to the present invention, a compact antenna configuration suitable for mounting on a portable wireless communication apparatus can suppress electromagnetic radiation forward and prevent a decrease in radiation efficiency, while simultaneously covering transmission and reception frequency bands. The bandwidth can be increased.
[Brief description of the drawings]
FIG. 1A is a diagram illustrating a configuration of an antenna device and a portable wireless communication device according to a first embodiment of the present invention. (B) The figure explaining the principle of the antenna apparatus which concerns on the 1st Embodiment of this invention. (C) The figure explaining the radiation pattern characteristic of the antenna apparatus which concerns on the 1st Embodiment of this invention. (D) The figure explaining the frequency characteristic of the antenna apparatus which concerns on the 1st Embodiment of this invention.
FIG. 2 is a diagram for explaining a configuration of an antenna device and a portable wireless communication device according to a second embodiment of the present invention.
FIG. 3 is a diagram illustrating a configuration of an antenna device according to a third embodiment of the present invention.
FIG. 4 is a diagram illustrating a configuration of an antenna device according to a fourth embodiment of the present invention.
FIG. 5 is a diagram illustrating a configuration of an antenna device according to a fifth embodiment of the present invention.
FIG. 6 is a diagram illustrating a configuration of an antenna device according to a sixth embodiment of the present invention.
FIG. 7 is a diagram illustrating a configuration of an antenna device according to a seventh embodiment of the present invention.
FIG. 8 is a diagram illustrating a configuration of an antenna device according to an eighth embodiment of the present invention.
FIG. 9 is a perspective view illustrating a configuration of an antenna device according to an eighth embodiment of the present invention.
FIG. 10 is a diagram showing frequency characteristics of an antenna device according to an eighth embodiment of the present invention.
FIG. 11 is a diagram showing a radiation pattern characteristic of an antenna device according to an eighth embodiment of the present invention.
[Explanation of symbols]
1 housing
2 Dipole antenna
21a, 21b Folded portions at both ends of dipole antenna
3 Feeding points
4 Handset
5 Counter element
51a, 51b Folded portions at opposite ends of the opposing element
6 Parasitic elements (1)
7 Parasitic elements (2)
8,9 Short circuit
10 Substrate

Claims

Power supply means are connected, and the dipole antenna configured to form a substantially line symmetric about a symmetry axis in a plane drive current vector belongs to occur when powered from said power supply means,
The plane is configured to be substantially line-symmetric with respect to the axis of symmetry, and disposed at a distance of a predetermined value or less with respect to the dipole antenna, and a first induction belonging to the plane by the drive current vector An opposing element made of a conductor from which a current vector is induced ;
An antenna device in which both end portions of the dipole antenna and both end portions of the opposing element are bent away from each other,
It is configured to be substantially line symmetric about the symmetry axis, and is disposed at a distance of a predetermined value or less from the dipole antenna on the opposite side of the opposing element across the dipole antenna . A first parasitic element comprising a conductor from which a second induced current vector is induced;
The first induction is configured to be substantially line symmetric about the axis of symmetry, and disposed at a distance not more than a predetermined value from the opposing element on the opposite side of the dipole antenna across the opposing element. An antenna device comprising: a second parasitic element including a conductor from which a third induced current vector is induced by a current vector.

A dipole antenna configured to be substantially line symmetric about a symmetry axis in a plane to which a driving current vector generated when a power feeding unit is connected and which is supplied with power from the power feeding unit;
The plane is configured to be substantially line-symmetric with respect to the axis of symmetry, and disposed at a distance of a predetermined value or less with respect to the dipole antenna, and a first induction belonging to the plane by the drive current vector An opposing element made of a conductor from which a current vector is induced;
An antenna device in which both end portions of the dipole antenna and both end portions of the opposing element are bent away from each other,
The dipole antenna located on one side with respect to the axis of symmetry and each end of the opposing element are disposed at a distance of a predetermined value or less, and a second current is generated by the drive current vector and the first induced current vector. A first parasitic element comprising a conductor from which an induced current vector is induced;
The dipole antenna located on the other side of the axis of symmetry and each end of the opposing element are disposed at a distance of a predetermined value or less, and a third current is generated by the driving current vector and the first induced current vector. A second parasitic element comprising a conductor from which an induced current vector is induced;
An antenna device comprising:

Each end of the dipole antenna and the opposing element located on one side with respect to the axis of symmetry is bent along a first straight line substantially parallel to the axis of symmetry, and on the other side with respect to the axis of symmetry. Each end of the dipole antenna and the opposing element positioned is bent along a second straight line substantially parallel to the symmetry axis, the first parasitic element located on one side with respect to the symmetry axis, Each end of the second parasitic element is bent along a third straight line substantially parallel to the symmetry axis, and the first parasitic element and the second parasitic element are located on the other side with respect to the symmetry axis. The antenna device according to claim 1, wherein each end of the parasitic element is bent along a fourth straight line substantially parallel to the symmetry axis .

Each end of the dipole antenna and the opposing element located on one side with respect to the axis of symmetry is bent along a first straight line substantially parallel to the axis of symmetry, and on the other side with respect to the axis of symmetry. The ends of the dipole antenna and the opposing element that are positioned are bent along a second straight line that is substantially parallel to the symmetry axis, and the first parasitic element is a third straight line that is substantially parallel to the symmetry axis. The antenna device according to claim 2 , wherein the second parasitic element is disposed along a fourth straight line substantially parallel to the axis of symmetry .

The line lengths of the dipole antenna and the opposing element are substantially equal, the line lengths of the first parasitic element and the second parasitic element are substantially equal, and are shorter than the line lengths of the dipole antenna and the opposing element. The antenna device according to claim 1 or 2 .

A main body provided with receiving means on the first plane;
Power supply means disposed in the main body;
A drive current vector is generated in a second plane parallel to the first plane when connected to the power supply means and supplied with power from the power supply means, and is substantially a line about a symmetry axis in the second plane. A dipole antenna configured to be symmetric,
The second plane is configured to be substantially line symmetric about the axis of symmetry, and is disposed at a distance of a predetermined value or less with respect to the dipole antenna, and the second plane is determined by the driving current vector. An opposing element made of a conductor from which a first induced current vector belonging to
A portable wireless communication device in which both end portions of the dipole antenna and both end portions of the opposing element are bent away from each other,
It is configured to be substantially line symmetric about the symmetry axis, and is disposed at a distance of a predetermined value or less from the dipole antenna on the opposite side of the opposing element across the dipole antenna. A first parasitic element comprising a conductor from which a second induced current vector is induced;
The first induction is configured to be substantially line symmetric about the axis of symmetry, and disposed at a distance not more than a predetermined value from the opposing element on the opposite side of the dipole antenna across the opposing element. A second parasitic element comprising a conductor from which a third induced current vector is induced by the current vector;
A portable wireless communication device comprising:

A main body provided with receiving means on the first plane;
Power supply means disposed in the main body;
A drive current vector is generated in a second plane parallel to the first plane when connected to the power supply means and supplied with power from the power supply means, and is substantially a line about a symmetry axis in the second plane. A dipole antenna configured to be symmetric,
The second plane is configured to be substantially line symmetric about the axis of symmetry, and is disposed at a distance of a predetermined value or less with respect to the dipole antenna, and the second plane is determined by the driving current vector. An opposing element made of a conductor from which a first induced current vector belonging to
A portable wireless communication device in which both end portions of the dipole antenna and both end portions of the opposing element are bent away from each other,
The dipole antenna located on one side with respect to the axis of symmetry and each end of the opposing element are disposed at a distance of a predetermined value or less, and a second current is generated by the drive current vector and the first induced current vector. A first parasitic element comprising a conductor from which an induced current vector is induced;
The dipole antenna located on the other side of the axis of symmetry and each end of the opposing element are disposed at a distance of a predetermined value or less, and a third current is generated by the driving current vector and the first induced current vector. A second parasitic element comprising a conductor from which an induced current vector is induced;
A portable wireless communication device comprising: