JP2004320431A

JP2004320431A - Flat antenna equipment

Info

Publication number: JP2004320431A
Application number: JP2003111355A
Authority: JP
Inventors: Akihiko Hayashi; 林　　昭彦
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2003-04-16
Filing date: 2003-04-16
Publication date: 2004-11-11
Anticipated expiration: 2023-04-16
Also published as: JP4443851B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide flat antenna equipment of which the development cost can be made low. <P>SOLUTION: The flat antenna equipment having a substrate 4 installed on one surface of a dielectric 1 has a recess 2 formed on the surface where the substrate 4 is installed, and is provided with a shield member 3 on the exposed surface of the recess 2. The substrate 4 has a circuit pattern 6a packaging circuits 7b provided on the installation surface to the dielectric 1 and has an outer radiation electrode 6b and an inner circuit grounded electrode 6a, which are connected in at least one position, provided on a surface opposite to the installation surface to the dielectric 1. The substrate 4 is installed on the dielectric 1 with a joining member like a detachable double-sided (adhesive) tape so that circuits 7b mounted on the substrate 4 through the circuit pattern 6a are stored in the recess 2 formed on the dielectric 1, and the shield member 3 and the circuit grounded electrode 6a are electrically connected at a prescribed pitch. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は平面アンテナ装置に関するものである。本発明による平面アンテナ装置は、例えば準マイクロ波を利用した衛星‐車両間通信用のＧＰＳ（グローバル・ポジショニング・システム）アンテナとして好適なものである。
【０００２】
【従来の技術】
近年、車載用ＧＰＳ（グローバル・ポジショニング・システム）用のアンテナとしては、マイクロストリップアンテナの利用が考えられ、その一種として平面アンテナ装置がある。
【０００３】
以下に従来の平面アンテナ装置について説明する。図１０は、特許文献１に記載されている平面アンテナ装置１００の構成を示す断面図である。この平面アンテナ装置１００は、誘電体１０１の上面に形成される導電性部材からなる放射電極部１０２と底面に形成される導電性部材からなる接地電極部１０４とを備える。誘電体１０１の底面の一部に段差部１０３（１０３ａ，１０３ｂ）が形成され、この段差部１０３（１０３ａ，１０３ｂ）には、放射電極部１０２と給電線路１０８によって電気的に接続されるものであって、回路素子１０６を搭載したプリント基板１０７からなる回路部１０５が収容される。更に、段差部１０３（１０３ａ，１０３ｂ）を密閉するための蓋部１０９を備えている。
【０００４】
【特許文献１】
特開平９−６４６３６号公報
【０００５】
【発明が解決しようとする課題】
しかしながら、図１０に示す従来技術では、放射電極１０２を誘電体１０１の一方の面に直接形成するものであり、通常、導電性部材を放射電極部１０２として機能させるためには、導電性部材を誘電体１０１上に形成した後に、トリミングして共振周波数を使用する周波数に合わせるように導電性部材の大きさや形状等を調整する必要がある。この調整が失敗した場合は、導電性部材が誘電体１０１に固着されているため誘電体１０１等は破棄するしかなく、誘電体１００は高価な部材であるため開発コストが高くなるという問題があった。
【０００６】
本発明は上記問題点に鑑みてなされたもので、放射電極の大きさや形状等の調整が失敗した場合でも、誘電体を破棄することなく不具合を解消可能な構造を有する平面アンテナ装置を提供することを目的とするものである。
【０００７】
【課題を解決するための手段】
上記目的を達成するため、請求項１に記載の発明では、電波を受信するアンテナとして機能する放射電極部を有する平面アンテナ装置において、誘電体と、誘電体の一面に配置された基板と、基板上に設けられた導電性部材を備え、放射電極部を導電性部材より構成したことを特徴とするものである。
【０００８】
これによれば、導電性部材からなる放射電極部を基板上に形成するため、放射電極部の大きさや形状等の調整を失敗した場合でも、高価な誘電体を破棄するのに比べ、放射電極部を形成する基板は安価であるため、開発コストを安くすることができる。
【０００９】
また、請求項２に記載の発明では、基板は誘電体より取り外し可能な状態で前記誘電体の一面に配置されてなることを特徴とするものである。これによれば、放射電極部の大きさや形状等の調整を失敗した場合でも、導電性部材からなる放射電極部を形成した基板を取り外すことができるため、安価な基板を取り外して新たな基板で再度調整を行うことができる。
【００１０】
また、請求項３記載の発明では、放射電極部により受信した電波を処理する回路部を有し、導電性部材における外側領域を放射電極部として設定すると共に、外側領域より内側の内側領域を回路部の回路接地電極部として設定することを特徴とするものである。これによれば、導電性部材の一部を回路接地電極部として使用するため、別途、回路部の接地電極を設ける必要がなくコストを安くすることができる。
【００１１】
また、請求項４に記載の発明では、導電性部材における放射電極部と回路接地電極部を少なくとも一箇所で電気的に接続し、受信信号は、この回路接地電極部を介して外部へ出力するようにすればよい。
【００１２】
また、請求項５に記載の発明では、外側領域は高周波電流の集中する箇所となる領域であることを特徴とするものである。これによれば、平面アンテナ装置として必要な箇所のみを放射電極部として使用し、平面アンテナ装置として必要ない箇所は回路接地電極部として使用するため、放射電極部のスペースを有効利用できる。
【００１３】
また、請求項６に記載の発明では、回路部は基板の導電性部材を設けた面とは反対の面に設けられ、誘電体には凹部が設けられ、凹部に回路部が収納された状態で基板が誘電体の一面に設置されてなることを特徴とするものである。これによれば、放射電極部と回路接地電極部と回路接地電極部に電気的に接続された回路部とを備えた基板を誘電体に実装するだけで良いため製造が容易になる。
【００１４】
また、請求項７に記載の発明では、凹部には第１シールド部材が形成され、第１シールド部材と回路接地電極部が回路部を取り囲むように所定のピッチで電気的に接続することを特徴とするものである。これによれば、回路部からの不要輻射を低減すると共に、回路部に対する干渉波を低減できる。
【００１５】
また、請求項８に記載の発明では、基板は、熱可塑性樹脂からなることを特徴とするものである。これによれば、基板の厚みを０．３ｍｍ程度まで薄くできるため
また、請求項９に記載の発明では、基板は、熱可塑性樹脂からなる多層基板より構成されるものであって、多層基板に回路部が内蔵され、回路部は多層基板に設けられたビアホールを介して回路接地電極部と電気的に接続されることを特徴とするものである。これによれば、誘電体に実装する基板に回路部を配置できるため、高価な誘電体に凹部を設ける必要がない。
【００１６】
また、請求項１０に記載の発明では、多層基板には第２シールド部材が内蔵され、第２シールド部材と回路接地電極部が回路部を取り囲むように所定のピッチで電気的に接続することを特徴とするものである。これによれば、回路部からの不要輻射を低減すると共に、回路部に対する干渉波を低減できる。
【００１７】
例えば、請求項１１に示すように、受信信号は、誘電体の基板が設けられる一面とは反対の面に給電部材を備え、この給電部材を介して外部へ出力するようにすればよい。
【００１８】
また、請求項１２に記載の発明では、誘電体の側面側から内蔵される給電部材を備え、放射電極部の受信信号を給電部材を介して外部へ出力することを特徴とするものである。これによれば、誘電体内部であり放射電極部に平行に給電部材を備えることができ、平面アンテナ装置全体の厚みを給電部材の厚み分だけ薄くできる。
【００１９】
【発明の実施の形態】
（第１実施形態）
以下、本発明の第１実施形態について、図１乃至図６を参照して説明する。図１は本発明の第１実施形態における平面アンテナ装置の斜視図である。図２は本発明の第１実施形態における平面アンテナ装置の断面図、図３は本発明の第１実施形態における平面アンテナ装置の表面側平面図、図４は本発明の第１実施形態における平面アンテナ装置の裏面側平面図、図５は本発明の第１実施形態における平面アンテナ装置の基板の断面図、図６は本発明の第１実施形態における回路ブロック図である。
【００２０】
２０は平面アンテナ装置である。平面アンテナ装置２０は、アンテナ素子部３０をレドーム１９内に収納し、このアンテナ素子部３０とレドーム１９とをブラケット１８に固定する。従って平面アンテナ装置は、ブラケット１８を介して任意の場所に配置される。
【００２１】
アンテナ素子部３０は、シールド部材３（本発明における第１シールド部材），接地電極部１０を有する誘電体１と電極部６（回路接地電極部６ａ（ＧＮＤ電極部とも称する）、放射電極部６ｂ（アンテナ部とも称する）），回路部７（回路パターン部７ａ、回路部品７ｂ）を有する基板４とからなる。
【００２２】
誘電体１は、図２に示すように一面に凹部２が形成され、この凹部２の露出面に回路シールド用のシールド部材３を有し、この凹部２の形成面（表面）とは反対側の面（裏面）には接地電極部１０を有する。更に、誘電体１及びシールド部材３には、回路パターン部７ａと電気的に接続する給電ピン１２を組込むための穴が形成されている。
【００２３】
また、誘電体１の材料としては、好ましくは高周波特性が良好で低損失なＰＰＳ（ポリフェニレンサルファイド：誘電率εｒ＝２０）を用いることにより、波長短縮効果によりアンテナ素子部の小型化が可能となる。
【００２４】
基板４は、図５に示すように表面側には、回路接地電極部６ａと放射電極部６ｂとを有し、裏面側には、回路部７（回路パターン部７ａ、回路部品７ｂ）を有する。この回路接地電極部６ａと回路部７（回路パターン部７ａ、回路部品７ｂ）とは、基板４に設けられたビアホール８を介して電気的に接続される。また、基板４にはシールド部材３を貫通するためのスリット５が設けられている。
【００２５】
基板４の材質としては、ガラス繊維を含有するエポキシ樹脂を用いることが一般的であるが、好ましくは、液晶ポリマーなどの熱可塑性樹脂を用いると良い。これにより、基板の厚みを０．３ｍｍ程度まで薄くできる。
【００２６】
電極部６は、外側にアンテナ電極として機能する放射電極部６ｂと、内側に回路ＧＮＤとして機能する回路接地電極部６ａとを有し、この放射電極部６ｂと回路接地電極部６ａとは少なくとも１箇所で接続されている。
【００２７】
基板４における表面側には回路接地電極部６ａが設けられ、裏面側には回路パターン部７ａが設けられ、回路部７は、回路パターン部７ａと、この回路パターン部７ａ上に実装された回路部品７ｂからなる。
【００２８】
回路部品７ｂは、図６に示すように、第１，第２増幅器、アンテナ整合回路，バイパスフィルタ、ノイズフィルタ等からなる。第１，第２増幅器は、放射電極部６ｂで受信した衛星からの電波を増幅するものである。アンテナ整合回路は、第１増幅器とアンテナのインピーダンスが異なる場合、信号の伝送損失が生じるため、アンテナのインピーダンスを第１増幅器のインピーダンス（通常５０Ω）に変換するための整合回路である。バイパスフィルタは、アンテナ装置にとっては必要な周波数以外の信号は、妨害，干渉等の悪影響を及ぼすものであり、その不必要な周波数の信号を除去するためのフィルタである。ノイズフィルタは、増幅器用の電源に重畳されているさまざまなノイズを除去するための回路である。
【００２９】
ここで本発明の平面アンテナ装置２０の製造方法に関して説明する。誘電体１に関しては、所定形状の金型内部に凹状の金属からなるシールド部材３と導電性部材からなる接地電極部１０を所定位置に設置した状態で、すなわちシールド部材３と接地電極部１０とをインサート成形するように射出成形されるものである。この際に、接地電極部１０は、基板４に設けられる電極部６と略同じ大きさの部材を用い、外側端部が揃う位置に配置される。更に、誘電体１及びシールド部材３には、回路部７の回路パターン部７ａと電気的に接続する給電ピン１２を組込むための穴が射出成形時、もしくは射出成形後に形成される。
【００３０】
基板４に関しては、まず、基板４の表面に形成される放射電極部６ｂの回路接地電極部６ａと基板の裏面に形成される回路パターン部７ａとを層間接続するためのビアホール８を設けると共に、基板４に形成される回路接地電極部６ａと誘電体１に形成されるシールド部材３とを電気的に接続するためのスリット５を設ける。
【００３１】
次に、基板４の表面側に回路接地電極部ａと放射電極部６ｂとを形成する。この放射電極部６ｂは、外側部（放射電極部６ｂ）と、この外側部（放射電極部６ｂ）とは少なくとも１箇所で接続される内側部（回路接地電極部６ａ）とからなるパターンを有するように、銅などの導電性部材をエッチングなどでパターニングする。その後、酸化防止のためのニッケルもしくは錫メッキを施す。なお、ビアホール８には、回路接地電極部６ａと放射電極部６ｂの形成前もしくは形成後に、層間接続材料を充填しておく。
【００３２】
次に、基板４の裏面側の回路部７を形成する。すなわち、まず表面側の回路接地電極部６ａに対向する位置において、銅などの導電性部材を所定の形状にエッチングなどでパターニングすることにより回路パターン部７ａを形成する。その後、周知の技術であるバンプなどを所定の位置に形成し、回路部品７ｂを実装する。
【００３３】
次に、各構成部品の組付けについて説明する。まず、基板４の裏面側に実装された回路部品７ｂを誘電体１の凹部２に収納するように誘電体１と基板４が取り外し可能な両面（粘着）テープなど接合部材にて誘電体１に基板４を設置する。この設置に関しては、誘電体１と基板４とが嵌合可能な構造を設け、両者を互いに固定するようにしてもよい。その際に、誘電体１の接地電極部１０から給電ピン１２を組込み、この給電ピン１２と回路パターン部７ａとを電気的に接続する。回路接地電極部６ａと放射電極部６ｂ側では、図３に示すように、誘電体１の凹部２内に形成されたシールド部材３を基板４に設けられたスリット５に貫通させ、シールド部材３と回路接地電極部６ａとを所定のピッチで半田接続する（半田９）。所定のピッチとは使用波長の１／２０波長であり、ＧＰＳの場合では約１０ｍｍ間隔にてＤＣ的な接続が必要である。
【００３４】
また、回路接地電極部６ａとシールド部材３との接続方法の変形例として、スリット５を形成する代わりに、基板にビアホールを設けるようにしても良い。この場合、シールド部材３を回路パターン部７ａに接続すると共に、ビアホールにて回路接地電極部６ａと回路パターン部７ａとを層間接続する。
【００３５】
ここで、基板４に形成された回路接地電極部６ａ及び放射電極部６ｂの形成位置について更に詳しく説明する。図１１は、図１０に示す従来技術のような放射電極部１０２の形状（ベタ状）と同様の放射電極を有する平面アンテナ装置を試験的に作成して調べた、高周波電流の分布を示すものである。この図からわかるように、高周波電流分布は放射電極の端部に集中しており、放射電極の中央付近にはほとんど存在していない。説明のために、この中央付近の高周波電流がほとんど存在していない内側の領域をＡとし、高周波電流の集中する箇所を含む外側の領域をＢとする。
【００３６】
領域Ａに関しては、高周波電流がほとんど存在しておらず、平面アンテナ装置の放射電極としては機能しない不要な領域であり、平面アンテナ装置の放射電極としては、高周波電流の集中する箇所を含む領域Ｂがあれば充分である。よって、本発明では、平面アンテナ装置の放射電極としては不要な領域Ａを回路接地電極部６ａとして用い、高周波電流の集中する箇所を含む領域Ｂのみを放射電極部６として用いる。
【００３７】
このようにして形成されたアンテナ素子部３０は、接地電極部１０側にて、同軸給電線１３の中心導体１４と給電ピン１２及び、同軸給電線１３の外導体１６と接地電極部１０とを半田接続（半田１７）する。この同軸給電線１３と接続されたアンテナ素子部３０は、樹脂製のレドーム１９内に収納された状態でブラケット１８に固定され、移動体などに搭載される。また、平面アンテナ装置２０は放射電極部６で受信した電波を、ビアホール８を介して回路部品７ｂへ入力し、回路部品７ｂで増幅等の処理を施された信号を給電部材１１（給電ピン１２及び同軸給電線１３）を介して出力する。
【００３８】
このように、導電性部材からなる放射電極部６ｂを基板４上に形成し、基板４を誘電体１から取り外し可能な構造にて基板４を誘電体１に設置するため、放射電極部６ｂの大きさや形状等の調整を失敗した場合でも、基板４のみを取り換えるだけですむため、高価な誘電体を破棄するのに比べ、放射電極部６ｂを形成する基板は安価であるため、開発コストを安くすることができる。また、導電性部材の一部をＧＮＤ部として使用するため、別途、回路部品のＧＮＤを設ける必要がなくコストを安くすることができる。更に、平面アンテナ装置２０として必要な箇所のみを放射電極部６ｂとして使用し、平面アンテナ装置として必要ない箇所は回路接地電極部６ａとして使用するため、放射電極部６のスペースを有効利用できる。
【００３９】
また、誘電体１の一面（基板４が実装される面）に基板４に搭載される回路部品７ｂを収納する凹部２設けることにより、基板４を誘電体１に実装するだけで平面アンテナ装置を形成できるため、別途回路用のＧＮＤを形成する必要がなく製造工程数が低減できる。
【００４０】
また、誘電体１に設けた凹部２に、回路部７を取り囲むようにシールド部材３を形成し、回路接地電極部６ａと所定のピッチで電気的に接続することにより、回路部７からの不要輻射を低減すると共に、回路部７に対する干渉波を低減できる。
【００４１】
また、シールド部材３に、凹部２の開口部側端部が基板４を貫通する貫通部を設けることにより、基板４を誘電体１に実装するだけで、シールド部材３の開口部側端部が基板４の回路接地電極部６ａと電気的に接続できる状態になるため製造が容易になる。
【００４２】
また、基板４として、熱可塑性樹脂を用いることにより、基板の厚みを０．３ｍｍ程度まで薄くできるため平面アンテナ装置全体としても薄型化ができる。
【００４３】
（第２実施形態）
次に、本発明の第２実施形態について、図７及び図８を参照して説明する。なお、第１実施形態との共通部分についての詳しい説明は省略する。
【００４４】
第１実施形態と本実施形態との相違点は、同軸給電線１３の配置場所にある。第１実施形態における同軸給電線１３は接地電極１０とブラケット１８との間に配置され、接地電極部１０から放射電極６側に向かって給電ピン１２を保持している。これに対して、本実施形態では、誘電体１の側面側から放射電極部と接地電極部との間に位置する部位に同軸給電線１３を組込む構成としている。
このような本実施形態によれば、誘電体内部であり放射電極部に平行に給電部材を備えることができ、平面アンテナ装置全体の厚みを同軸給電線１３の厚み分だけ薄くできる。
【００４５】
（変形例）
変形例として、基板４を、熱可塑性樹脂からなる多層基板としてもよい。製造方法に関しては、複数の熱可塑性樹脂からなる樹脂フィルムを積層するものであり、樹脂フィルムに貫通孔を設けることによって回路部品７ｂを収納する空間部を形成する。この空間部の少なくとも１つの面に回路部品７ｂが電気的に接続される回路パターン７ａを形成し、樹脂フィルムを積層する際に回路部品７ｂを空間部に配置すると共に、空間部の開口部側（上面）にも樹脂フィルムを積層する。また、積層された樹脂フィルムの最上部の表面側には、回路接地電極部６ａ及び放射電極部６ｂを形成し、回路接地電極部６ａと回路パターン７ａはビアホールにて電気的に接続できるようにしておく。更に、回路部品７ｂの配置された空間部の周囲を囲うようにビアホール及び導電性パターンを形成し、ビアホールに関しては回路接地電極部６ａに達するように形成しておく。
【００４６】
このような空間部に回路部品７ｂを配置しつつ積層された樹脂フィルムを積層後加圧しつつ加熱して相互に接着することによって、回路パターン部７ａは回路接地電極部６ａ及び回路部品７ｂと電気的に接続される。更に、回路部品７ｂの配置された空間部の周囲を囲うように形成されたビアホールと導電性パターンも相互に電気的に接続され、回路接地電極部６ａと所定のピッチで半田接続することによってシールド部材（本発明における第２シールド部材）となる。なお、シールド部材に関しては、ビアホールと導電性パターンとで構成されるもの以外でも、所定形状の導電性部材を樹脂フィルムを貫通させて形成するものであっても良い。
【００４７】
このように熱可塑性樹脂からなる多層基板に空間部を設け、その空間部内に回路部品７ｂを設ける共に、空間部の周囲をシールド部材で囲うことによって、高価な誘電体１に凹部２を設ける必要がなくなる。
【００４８】
なお、本発明における平面アンテナ装置のアンテナ単品指向性を図９に示す。図９ｂから明らかなように、天頂方向（Ｚ方向）において所望の＋４ｄＢｉｃを得ることができる。
【図面の簡単な説明】
【図１】本発明の第１実施形態における平面アンテナ装置の斜視図である。
【図２】本発明の第１実施形態における平面アンテナ装置の断面図である。
【図３】本発明の第１実施形態における平面アンテナ装置の表面側平面図である。
【図４】本発明の第１実施形態における平面アンテナ装置の裏面側平面図である。
【図５】本発明の第１実施形態における平面アンテナ装置の基板の断面図である。
【図６】本発明における平面アンテナ装置の回路ブロック図である。
【図７】本発明の第２実施形態における平面アンテナ装置の斜視図である。
【図８】本発明の第２実施形態における平面アンテナ装置の断面図である。
【図９】本発明における平面アンテナ装置の指向性の説明図である。
【図１０】従来技術における平面アンテナ装置の断面図である。
【図１１】従来技術における放射電極と同形状の平面アンテナ装置における高周波電流分布図である。
【符号の説明】
１誘電体、２凹部、３シールド部材、４基板、５スリット、６放射電極部、６ａ回路接地電極部、６ｂ放射電極部、７回路部、７ａ回路パターン部、７ｂ回路部品、８ビアホール、９半田接続部、１０接地電極、１１給電部材[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a planar antenna device. The planar antenna device according to the present invention is suitable as a GPS (global positioning system) antenna for satellite-vehicle communication using quasi-microwaves, for example.
[0002]
[Prior art]
2. Description of the Related Art In recent years, as an antenna for a GPS (Global Positioning System) for a vehicle, a microstrip antenna is considered to be used.
[0003]
Hereinafter, a conventional planar antenna device will be described. FIG. 10 is a cross-sectional view showing the configuration of the planar antenna device 100 described in Patent Document 1. The planar antenna device 100 includes a radiation electrode section 102 made of a conductive member formed on an upper surface of a dielectric 101 and a ground electrode section 104 made of a conductive member formed on a bottom surface. A step 103 (103a, 103b) is formed on a part of the bottom surface of the dielectric 101, and the step 103 (103a, 103b) is electrically connected to the radiation electrode 102 and the feed line 108. In addition, a circuit section 105 including a printed circuit board 107 on which a circuit element 106 is mounted is accommodated. Further, a lid 109 for sealing the step portion 103 (103a, 103b) is provided.
[0004]
[Patent Document 1]
JP-A-9-64636 [0005]
[Problems to be solved by the invention]
However, in the prior art shown in FIG. 10, the radiation electrode 102 is formed directly on one surface of the dielectric 101, and usually, in order for the conductive member to function as the radiation electrode unit 102, the conductive member is After being formed on the dielectric 101, it is necessary to trim and adjust the size and shape of the conductive member so as to match the resonance frequency to the frequency to be used. If this adjustment fails, the dielectric member 101 and the like must be discarded because the conductive member is fixed to the dielectric member 101, and the dielectric member 100 is an expensive member, which increases the development cost. Was.
[0006]
The present invention has been made in view of the above problems, and provides a planar antenna device having a structure capable of solving a problem without discarding a dielectric even when adjustment of the size or shape of a radiation electrode or the like fails. It is intended for that purpose.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, in a flat antenna device having a radiation electrode portion functioning as an antenna for receiving a radio wave, a dielectric, a substrate disposed on one surface of the dielectric, It is characterized by comprising a conductive member provided thereon, and the radiation electrode portion being formed of a conductive member.
[0008]
According to this, since the radiation electrode portion made of a conductive member is formed on the substrate, even if the adjustment of the size or shape of the radiation electrode portion fails, compared to discarding the expensive dielectric material, Since the substrate forming the portion is inexpensive, the development cost can be reduced.
[0009]
According to a second aspect of the present invention, the substrate is disposed on one surface of the dielectric so as to be detachable from the dielectric. According to this, even if the adjustment of the size, shape, etc. of the radiation electrode portion fails, the substrate on which the radiation electrode portion made of a conductive member is formed can be removed. The adjustment can be performed again.
[0010]
Further, according to the third aspect of the present invention, there is provided a circuit unit for processing a radio wave received by the radiation electrode unit, the outer region of the conductive member is set as the radiation electrode unit, and the inner region inside the outer region is set as a circuit. It is set as a circuit ground electrode part of the section. According to this, since a part of the conductive member is used as the circuit ground electrode portion, it is not necessary to separately provide a ground electrode of the circuit portion, and the cost can be reduced.
[0011]
According to the fourth aspect of the present invention, the radiation electrode section and the circuit ground electrode section of the conductive member are electrically connected at at least one place, and a reception signal is output to the outside via the circuit ground electrode section. What should I do?
[0012]
In the invention according to claim 5, the outer region is a region where a high-frequency current is concentrated. According to this, only the portion required for the planar antenna device is used as the radiation electrode portion, and the portion not required for the planar antenna device is used as the circuit ground electrode portion, so that the space of the radiation electrode portion can be effectively used.
[0013]
In the invention according to claim 6, the circuit portion is provided on the surface of the substrate opposite to the surface on which the conductive member is provided, the dielectric is provided with a concave portion, and the circuit portion is housed in the concave portion. Wherein the substrate is disposed on one surface of the dielectric. According to this, the substrate having the radiation electrode section, the circuit ground electrode section, and the circuit section electrically connected to the circuit ground electrode section only needs to be mounted on the dielectric, thereby facilitating the manufacture.
[0014]
Further, in the invention according to claim 7, a first shield member is formed in the concave portion, and the first shield member and the circuit ground electrode portion are electrically connected at a predetermined pitch so as to surround the circuit portion. It is assumed that. According to this, unnecessary radiation from the circuit unit can be reduced, and interference waves to the circuit unit can be reduced.
[0015]
Further, in the invention according to claim 8, the substrate is made of a thermoplastic resin. According to this, since the thickness of the substrate can be reduced to about 0.3 mm, in the invention according to claim 9, the substrate is constituted by a multilayer substrate made of a thermoplastic resin. A circuit portion is built in, and the circuit portion is electrically connected to a circuit ground electrode portion through a via hole provided in the multilayer substrate. According to this, since the circuit portion can be arranged on the substrate mounted on the dielectric, there is no need to provide a concave portion in the expensive dielectric.
[0016]
According to the tenth aspect of the present invention, the second shield member is incorporated in the multilayer substrate, and the second shield member and the circuit ground electrode portion are electrically connected at a predetermined pitch so as to surround the circuit portion. It is a feature. According to this, unnecessary radiation from the circuit unit can be reduced, and interference waves to the circuit unit can be reduced.
[0017]
For example, as set forth in claim 11, a power supply member may be provided on a surface opposite to the surface on which the dielectric substrate is provided, and may be output to the outside via the power supply member.
[0018]
According to a twelfth aspect of the present invention, there is provided a power supply member built in from the side surface of the dielectric, and a reception signal of the radiation electrode unit is output to the outside via the power supply member. According to this, the feed member can be provided inside the dielectric and parallel to the radiation electrode portion, and the thickness of the entire planar antenna device can be reduced by the thickness of the feed member.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
(1st Embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of the planar antenna device according to the first embodiment of the present invention. 2 is a sectional view of the planar antenna device according to the first embodiment of the present invention, FIG. 3 is a front plan view of the planar antenna device according to the first embodiment of the present invention, and FIG. 4 is a plan view of the planar antenna device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a substrate of the planar antenna device according to the first embodiment of the present invention, and FIG. 6 is a circuit block diagram according to the first embodiment of the present invention.
[0020]
Reference numeral 20 denotes a planar antenna device. In the planar antenna device 20, the antenna element unit 30 is housed in the radome 19, and the antenna element unit 30 and the radome 19 are fixed to the bracket 18. Therefore, the planar antenna device is arranged at an arbitrary position via the bracket 18.
[0021]
The antenna element section 30 includes a shield member 3 (a first shield member in the present invention), a dielectric 1 having a ground electrode section 10, an electrode section 6 (a circuit ground electrode section 6a (also referred to as a GND electrode section), and a radiation electrode section 6b). (Also referred to as an antenna section)) and a substrate 4 having a circuit section 7 (circuit pattern section 7a, circuit component 7b).
[0022]
As shown in FIG. 2, the dielectric 1 has a concave portion 2 formed on one surface, and has a shield member 3 for circuit shielding on an exposed surface of the concave portion 2, and is opposite to a surface (surface) on which the concave portion 2 is formed. (Rear surface) has a ground electrode portion 10. Further, the dielectric 1 and the shield member 3 are formed with holes for incorporating the power supply pins 12 electrically connected to the circuit pattern portion 7a.
[0023]
Further, as the material of the dielectric 1, preferably, PPS (polyphenylene sulfide: dielectric constant εr = 20) having good high-frequency characteristics and low loss is used, so that the antenna element can be reduced in size due to a wavelength shortening effect. .
[0024]
As shown in FIG. 5, the substrate 4 has a circuit ground electrode portion 6a and a radiation electrode portion 6b on the front surface side, and has a circuit portion 7 (a circuit pattern portion 7a and a circuit component 7b) on the back surface side. . The circuit ground electrode section 6a and the circuit section 7 (circuit pattern section 7a, circuit component 7b) are electrically connected via via holes 8 provided in the substrate 4. Further, a slit 5 for penetrating the shield member 3 is provided in the substrate 4.
[0025]
As a material of the substrate 4, an epoxy resin containing glass fiber is generally used, but a thermoplastic resin such as a liquid crystal polymer is preferably used. Thereby, the thickness of the substrate can be reduced to about 0.3 mm.
[0026]
The electrode portion 6 has a radiation electrode portion 6b functioning as an antenna electrode on the outside, and a circuit ground electrode portion 6a functioning as a circuit GND on the inside, and the radiation electrode portion 6b and the circuit ground electrode portion 6a are at least one. Connected at the point.
[0027]
A circuit ground electrode portion 6a is provided on the front side of the substrate 4 and a circuit pattern portion 7a is provided on the back side. The circuit portion 7 includes a circuit pattern portion 7a and a circuit mounted on the circuit pattern portion 7a. It consists of a part 7b.
[0028]
As shown in FIG. 6, the circuit component 7b includes first and second amplifiers, an antenna matching circuit, a bypass filter, a noise filter, and the like. The first and second amplifiers amplify radio waves from satellites received by the radiation electrode unit 6b. The antenna matching circuit is a matching circuit for converting the impedance of the antenna into the impedance of the first amplifier (usually 50Ω) because a signal transmission loss occurs when the impedance of the first amplifier and the antenna are different. The bypass filter is a filter for removing a signal of an unnecessary frequency because a signal other than a frequency necessary for the antenna device has an adverse effect such as interference or interference. The noise filter is a circuit for removing various noises superimposed on the power supply for the amplifier.
[0029]
Here, a method for manufacturing the planar antenna device 20 of the present invention will be described. With respect to the dielectric 1, a shield member 3 made of a concave metal and a ground electrode portion 10 made of a conductive member are installed at predetermined positions inside a mold having a predetermined shape, that is, the shield member 3 and the ground electrode portion 10 Is injection molded so as to perform insert molding. At this time, the ground electrode unit 10 uses a member having substantially the same size as the electrode unit 6 provided on the substrate 4 and is arranged at a position where the outer ends are aligned. Further, holes for incorporating the power supply pins 12 electrically connected to the circuit pattern portion 7a of the circuit portion 7 are formed in the dielectric 1 and the shield member 3 during or after the injection molding.
[0030]
Regarding the substrate 4, first, a via hole 8 for interlayer connection between the circuit ground electrode portion 6a of the radiation electrode portion 6b formed on the surface of the substrate 4 and the circuit pattern portion 7a formed on the back surface of the substrate 4 is provided. A slit 5 for electrically connecting a circuit ground electrode portion 6a formed on the substrate 4 and the shield member 3 formed on the dielectric 1 is provided.
[0031]
Next, a circuit ground electrode portion a and a radiation electrode portion 6b are formed on the front surface side of the substrate 4. The radiation electrode portion 6b has a pattern including an outer portion (radiation electrode portion 6b) and an inner portion (circuit ground electrode portion 6a) connected to the outer portion (radiation electrode portion 6b) at at least one place. As described above, a conductive member such as copper is patterned by etching or the like. Thereafter, nickel or tin plating for oxidation prevention is performed. The via hole 8 is filled with an interlayer connection material before or after the formation of the circuit ground electrode portion 6a and the radiation electrode portion 6b.
[0032]
Next, the circuit section 7 on the back surface side of the substrate 4 is formed. That is, first, at a position facing the circuit ground electrode portion 6a on the front surface side, a circuit member 7a is formed by patterning a conductive member such as copper into a predetermined shape by etching or the like. Thereafter, a bump or the like, which is a well-known technique, is formed at a predetermined position, and the circuit component 7b is mounted.
[0033]
Next, the assembly of each component will be described. First, the dielectric component 1 and the substrate 4 are attached to the dielectric 1 by a bonding member such as a removable double-sided (adhesive) tape so that the circuit component 7b mounted on the back surface side of the substrate 4 is housed in the concave portion 2 of the dielectric 1. The substrate 4 is set. Regarding this installation, a structure in which the dielectric 1 and the substrate 4 can be fitted may be provided, and the two may be fixed to each other. At this time, a power supply pin 12 is assembled from the ground electrode portion 10 of the dielectric 1, and the power supply pin 12 and the circuit pattern portion 7a are electrically connected. On the circuit ground electrode portion 6a and the radiation electrode portion 6b side, as shown in FIG. 3, the shield member 3 formed in the concave portion 2 of the dielectric 1 is passed through the slit 5 provided in the substrate 4, and the shield member 3 And the circuit ground electrode portion 6a are soldered at a predetermined pitch (solder 9). The predetermined pitch is 1/20 wavelength of the used wavelength, and in the case of GPS, DC connection is required at intervals of about 10 mm.
[0034]
As a modification of the method of connecting the circuit ground electrode portion 6a and the shield member 3, a via hole may be provided in the substrate instead of forming the slit 5. In this case, the shield member 3 is connected to the circuit pattern portion 7a, and the circuit ground electrode portion 6a and the circuit pattern portion 7a are interlayer-connected by via holes.
[0035]
Here, the formation positions of the circuit ground electrode portion 6a and the radiation electrode portion 6b formed on the substrate 4 will be described in more detail. FIG. 11 shows a distribution of a high-frequency current obtained by experimentally preparing and examining a planar antenna device having a radiation electrode having the same shape (solid shape) of the radiation electrode portion 102 as the conventional technique shown in FIG. It is. As can be seen from this figure, the high-frequency current distribution is concentrated at the end of the radiation electrode, and hardly exists near the center of the radiation electrode. For the sake of explanation, the inner region near the center where the high-frequency current hardly exists is denoted by A, and the outer region including the portion where the high-frequency current is concentrated is denoted by B.
[0036]
The area A is an unnecessary area where the high-frequency current hardly exists and does not function as the radiation electrode of the planar antenna device. The area B including the portion where the high-frequency current is concentrated is used as the radiation electrode of the planar antenna apparatus. Is enough. Therefore, in the present invention, the area A unnecessary as the radiation electrode of the planar antenna device is used as the circuit ground electrode section 6a, and only the area B including the portion where the high-frequency current is concentrated is used as the radiation electrode section 6.
[0037]
The antenna element unit 30 formed in this manner connects the center conductor 14 of the coaxial feed line 13 and the feed pin 12 and the outer conductor 16 of the coaxial feed line 13 and the ground electrode unit 10 on the ground electrode unit 10 side. Solder connection (solder 17). The antenna element unit 30 connected to the coaxial feed line 13 is fixed to the bracket 18 while being housed in the resin radome 19, and is mounted on a moving body or the like. Further, the planar antenna device 20 inputs a radio wave received by the radiation electrode unit 6 to the circuit component 7b through the via hole 8, and transmits a signal subjected to processing such as amplification by the circuit component 7b to the power supply member 11 (the power supply pin 12). And output via a coaxial feed line 13).
[0038]
As described above, the radiation electrode portion 6b made of a conductive member is formed on the substrate 4, and the substrate 4 is placed on the dielectric 1 in a structure in which the substrate 4 can be detached from the dielectric 1. Even if the adjustment of the size and shape is unsuccessful, only the substrate 4 needs to be replaced. Therefore, compared to discarding an expensive dielectric, the substrate forming the radiation electrode portion 6b is inexpensive. Can be cheaper. In addition, since a part of the conductive member is used as the GND portion, it is not necessary to separately provide a GND of a circuit component, and the cost can be reduced. Furthermore, only the portion required for the planar antenna device 20 is used as the radiation electrode portion 6b, and the portion not required for the planar antenna device is used as the circuit ground electrode portion 6a, so that the space of the radiation electrode portion 6 can be effectively used.
[0039]
Further, by providing the concave portion 2 for accommodating the circuit component 7b mounted on the substrate 4 on one surface of the dielectric 1 (the surface on which the substrate 4 is mounted), the planar antenna device can be realized by simply mounting the substrate 4 on the dielectric 1. Since it can be formed, it is not necessary to separately form a GND for a circuit, and the number of manufacturing steps can be reduced.
[0040]
Further, the shield member 3 is formed in the concave portion 2 provided in the dielectric 1 so as to surround the circuit portion 7 and is electrically connected to the circuit ground electrode portion 6a at a predetermined pitch, so that unnecessary portions from the circuit portion 7 can be obtained. Radiation can be reduced, and interference waves to the circuit section 7 can be reduced.
[0041]
In addition, by providing the shield member 3 with a penetrating portion in which the opening-side end of the concave portion 2 penetrates the substrate 4, the opening-side end of the shield member 3 can be formed only by mounting the substrate 4 on the dielectric 1. Since it can be electrically connected to the circuit ground electrode portion 6a of the substrate 4, manufacturing becomes easy.
[0042]
Further, by using a thermoplastic resin as the substrate 4, the thickness of the substrate can be reduced to about 0.3 mm, so that the overall planar antenna device can be made thin.
[0043]
(2nd Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. Note that a detailed description of common parts with the first embodiment will be omitted.
[0044]
The difference between the first embodiment and the present embodiment lies in the location of the coaxial feed line 13. The coaxial power supply line 13 in the first embodiment is disposed between the ground electrode 10 and the bracket 18, and holds the power supply pin 12 from the ground electrode unit 10 toward the radiation electrode 6. On the other hand, in the present embodiment, the coaxial power supply line 13 is incorporated into a portion located between the radiation electrode unit and the ground electrode unit from the side surface of the dielectric 1.
According to the present embodiment, a feeder member can be provided inside the dielectric and parallel to the radiation electrode portion, and the overall thickness of the planar antenna device can be reduced by the thickness of the coaxial feeder 13.
[0045]
(Modification)
As a modification, the substrate 4 may be a multilayer substrate made of a thermoplastic resin. Regarding the manufacturing method, a resin film made of a plurality of thermoplastic resins is laminated, and a through hole is provided in the resin film to form a space for accommodating the circuit component 7b. A circuit pattern 7a to which the circuit component 7b is electrically connected is formed on at least one surface of the space, and when the resin film is laminated, the circuit component 7b is arranged in the space and the opening side of the space is opened. A resin film is also laminated on the (upper surface). A circuit ground electrode portion 6a and a radiation electrode portion 6b are formed on the uppermost surface side of the laminated resin film so that the circuit ground electrode portion 6a and the circuit pattern 7a can be electrically connected to each other through a via hole. Keep it. Further, a via hole and a conductive pattern are formed so as to surround the space where the circuit component 7b is arranged, and the via hole is formed so as to reach the circuit ground electrode portion 6a.
[0046]
The circuit pattern portion 7a is electrically connected to the circuit ground electrode portion 6a and the circuit component 7b by arranging the resin films laminated while placing the circuit component 7b in such a space and then heating the resin film while applying pressure and bonding them together. Connected. Further, a via hole formed so as to surround the periphery of the space where the circuit component 7b is arranged and the conductive pattern are also electrically connected to each other, and are shielded by soldering with a predetermined pitch to the circuit ground electrode 6a. The member (the second shield member in the present invention). In addition, as for the shield member, a conductive member having a predetermined shape may be formed by penetrating the resin film other than the one formed by the via hole and the conductive pattern.
[0047]
As described above, it is necessary to provide the concave portion 2 in the expensive dielectric 1 by providing the space portion on the multilayer substrate made of the thermoplastic resin, providing the circuit component 7b in the space portion, and surrounding the space portion with the shield member. Disappears.
[0048]
FIG. 9 shows the directivity of a single antenna of the planar antenna device according to the present invention. As is clear from FIG. 9B, a desired +4 dBic can be obtained in the zenith direction (Z direction).
[Brief description of the drawings]
FIG. 1 is a perspective view of a planar antenna device according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of the planar antenna device according to the first embodiment of the present invention.
FIG. 3 is a front side plan view of the planar antenna device according to the first embodiment of the present invention.
FIG. 4 is a rear side plan view of the planar antenna device according to the first embodiment of the present invention.
FIG. 5 is a sectional view of a substrate of the planar antenna device according to the first embodiment of the present invention.
FIG. 6 is a circuit block diagram of the planar antenna device according to the present invention.
FIG. 7 is a perspective view of a planar antenna device according to a second embodiment of the present invention.
FIG. 8 is a sectional view of a planar antenna device according to a second embodiment of the present invention.
FIG. 9 is an explanatory diagram of directivity of the planar antenna device according to the present invention.
FIG. 10 is a cross-sectional view of a planar antenna device according to the related art.
FIG. 11 is a diagram illustrating a high-frequency current distribution in a planar antenna device having the same shape as a radiation electrode according to the related art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Dielectric, 2 recessed parts, 3 shield members, 4 substrates, 5 slits, 6 radiation electrode portions, 6a circuit ground electrode portions, 6b radiation electrode portions, 7 circuit portions, 7a circuit pattern portions, 7b circuit components, 8 via holes, 9 Solder connection part, 10 ground electrode, 11 power supply member

Claims

In a planar antenna device having a radiation electrode portion functioning as an antenna for receiving radio waves,
A dielectric, a substrate provided on one surface of the dielectric, and a conductive member provided on the substrate,
The planar antenna device, wherein the radiation electrode portion is formed of the conductive member.

The planar antenna device according to claim 1, wherein the substrate is disposed on the one surface of the dielectric so as to be detachable from the dielectric.

Having a circuit unit for processing radio waves received by the radiation electrode unit,
3. The method according to claim 1, wherein an outer region of the conductive member is set as the radiation electrode portion, and an inner region inside the outer region is set as a circuit ground electrode portion of the circuit portion. The planar antenna device according to any one of the preceding claims.

The planar antenna device according to claim 3, wherein the radiation electrode section and the circuit ground electrode section of the conductive member are electrically connected at at least one place.

The planar antenna device according to claim 3, wherein the outer region is a region where a high-frequency current is concentrated.

The circuit unit is provided on a surface of the substrate opposite to a surface on which the conductive member is provided,
6. The dielectric body according to claim 3, wherein a concave part is provided in the dielectric body, and the substrate is set on the one surface of the dielectric body in a state where the circuit part is housed in the concave part. A planar antenna device according to any one of the above.

7. The device according to claim 6, wherein a first shield member is formed in the concave portion, and the first shield member and the circuit ground electrode portion are electrically connected at a predetermined pitch so as to surround the circuit portion. Flat antenna device.

The planar antenna device according to claim 1, wherein the substrate is made of a thermoplastic resin.

The substrate is configured by a multilayer substrate made of a thermoplastic resin,
6. The circuit unit according to claim 1, wherein the circuit unit is built in the multilayer substrate, and the circuit unit is electrically connected to the circuit ground electrode unit via a via hole provided in the multilayer substrate. The planar antenna device according to any one of the above.

10. The multi-layer substrate according to claim 9, wherein a second shield member is built in, and the second shield member and the circuit ground electrode portion are electrically connected at a predetermined pitch so as to surround the circuit portion. The planar antenna device according to any one of the preceding claims.

A power supply member is provided on a surface opposite to the one surface on which the substrate of the dielectric is provided,
The planar antenna device according to any one of claims 1 to 10, wherein a reception signal of the radiation electrode unit is output to the outside via the power supply member.

A power supply member built in from the side of the dielectric,
The planar antenna device according to any one of claims 1 to 10, wherein a reception signal of the radiation electrode unit is output to the outside via the power supply member.