JP3600799B2

JP3600799B2 - Non-radiative dielectric line and millimeter wave transceiver

Info

Publication number: JP3600799B2
Application number: JP2001055331A
Authority: JP
Inventors: 健岡村; 信樹平松
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2001-02-28
Filing date: 2001-02-28
Publication date: 2004-12-15
Anticipated expiration: 2021-02-28
Also published as: JP2002261515A

Description

【０００１】
【発明の属する技術分野】
本発明は、例えばミリ波等の高周波帯域で用いられる非放射性誘電体線路であって、ミリ波集積回路等に好適に使用されるものに関するものであり、また非放射性誘電体線路型のミリ波集積回路，ミリ波レーダーモジュール等のミリ波送受信器に関するものである。
【０００２】
【従来の技術】
従来の非放射性誘電体線路（Nonradiative Dielectric Waveguideで、以下、ＮＲＤガイドという）Ｓ１の構成を図２に示す。図２のＮＲＤガイドＳ１は、使用周波数において空気中を伝搬する電磁波（高周波信号）の波長λに対して、間隔ｄがλ／２以下である一対の平行平板導体１１，１３の間に誘電体線路１２を介装することにより、その誘電体線路１２に沿って電磁波が伝搬でき、放射波は平行平板導体１１，１３の遮断効果によって抑制されるという動作原理に基づいている。
【０００３】
このＮＲＤガイドＳ１の電磁波伝搬モードとしては、ＬＳＭモード，ＬＳＥモードの２種類があることが知られているが、損失の小さいＬＳＭモードが一般的に使用されている。また、ＮＲＤガイドの他のタイプとして、図３のような曲線状の誘電体線路１４を設けたＮＲＤガイドＳ２もあり、これにより電磁波を容易に曲線的に伝搬させることができ、ミリ波集積回路の小型化や自由度の高い回路設計ができるという利点を持っている。
【０００４】
なお、図２および図３において、上側の平行平板導体１３は内部を透視するように一部を切り欠くか、破線で示した。また、１１は下側の平行平板導体である。
【０００５】
また、従来、ＮＲＤガイドＳ１，Ｓ２の誘電体線路１２，１４の材料としては、手軽に加工できるという簡便さと低損失という点で、テフロン（登録商標），ポリスチレン等の比誘電率２〜４の樹脂材料が使われてきた。
【０００６】
【発明が解決しようとする課題】
しかしながら、従来用いられてきたテフロン，ポリスチレン等の比誘電率２〜４の誘電体からなる誘電体線路１２，１４でＮＲＤガイドＳ１，Ｓ２を構成すると、曲線部での曲げ損失や、誘電体線路１２，１４の接合部での損失が大きいという欠点があった。このため、急峻な曲線部を設けることができなかった。また、緩やかな曲線部とした場合にも、その曲線部の曲率半径を精密に決定する必要があった。さらに、小さい曲げ損失でもって使用可能な周波数範囲が、例えば６０ＧＨｚ付近では１〜２ＧＨｚと十分ではなかった。これは、比誘電率が２〜４の誘電体を用いてＮＲＤガイドＳ１，Ｓ２を構成した場合、上記ＬＳＭモードとＬＳＥモードの分散曲線が非常に近いため、ＬＳＭモードの電磁波の一部がＬＳＥモードに変換されてしまい、損失が増大するためであった。
【０００７】
また、誘電体線路１２，１４の材料として、アルミナ（Ａｌ_２Ｏ_３）セラミックス等の比誘電率が１０程度のセラミックスを用いたものもあるが、５０ＧＨｚ以上の高周波で使用するためには、誘電体線路１２，１４の幅を非常に細くしなければならず、加工性および実装上実用的ではない。
【０００８】
また、セラミックス等の無機化合物からなる誘電体線路１２，１４を用いたＮＲＤガイドにより高周波デバイス，高周波回路モジュールを作製した場合、誘電体線路１２，１４に急峻な曲線部を設けることはできるが、複数の直線部と曲線部から成るような複雑形状を作製することは困難であった。さらに、平行平板導体１１，１３と誘電体線路１２，１４との熱膨張係数の差、さらには衝撃により誘電体線路１２，１４に破損が生じる等の問題があった。
【０００９】
また、従来用いられてきたテフロン等の樹脂材料からなる誘電体線路でＮＲＤガイドを構成すると、誘電体線路１２，１４と平行平板導体１１，１３の接着が難しく、振動や熱膨張差によって誘電体線路１２，１４が位置ずれを起こし、正常に機能しなくなるという問題があった。
【００１０】
従って、本発明は上記事情に鑑みて完成されたものであり、その目的は、ＬＳＭモードの電磁波のＬＳＥモードへの変換が少なく、従って誘電体線路に小さい曲率半径で使用周波数範囲が広い急峻な曲線部を作製することができ、その結果、ミリ波集積回路等を小型化でき、信頼性が高く、また高周波信号の損失が小さい高性能なＮＲＤガイドを提供することである。また、このようなＮＲＤガイドを用いることにより、高周波信号の伝送損失が小さく、小型化されたミリ波送受信器を提供することである。
【００１１】
【課題を解決するための手段】
本発明の非放射性誘電体線路は、高周波信号の波長λの２分の１以下の間隔で配置した平行平板導体間に前記高周波信号を伝送する誘電体線路を介装して成る非放射性誘電体線路において、前記誘電体線路は、複数の誘電体線路部分の端面同士を対向させて構成されているとともに、前記誘電体線路部分を設置する平行平板導体の部位に誘電体線路部分の幅よりも幅広な溝で誘電体線路部分全体を嵌め込むことができるような溝を形成し、その溝内で誘電体線路部分の設置位置を調整することによって、前記誘電体線路部分が隣接するものに対してその前記端面同士が前記高周波信号の伝送方向に直交し、かつ前記平行平板導体の内面に平行な方向にλ／８以下の距離を移動可能に設置されていることを特徴とする。
【００１２】
本発明のＮＲＤガイドは、複数の誘電体線路部分を擬似的に一本の誘電体線路となるように連続的に設置することで、直線部と曲線部からなる複雑形状の誘電体線路を容易に作製することができる。このようにして、より自由度と信頼性が高く、小型で安価で損失が小さい高性能なＮＲＤガイドを構成することができる。その結果、ミリ波集積回路等を小型化でき、信頼性が高く、また高周波信号の損失が小さい高性能なＮＲＤガイドとなる。
【００１３】
また、上記のような誘電体線路部分を移動させる手段によって、誘電体線路部分が隣接するものに対して高周波信号の伝送方向に直交し、かつ平行平板導体の内面に平行な方向にλ／８以下の距離を移動可能に設置されていることにより、高周波信号の伝送特性を維持した状態で、誘電体線路部分と電磁結合している、高周波ダイオード等の他の部品や他の誘電体線路との間隔を制御できる。これにより、高周波ダイオードの発振周波数を制御したり、他の誘電体線路とのカップリングの度合い等を制御できる。
【００１４】
本発明のミリ波送受信器は、ミリ波信号の波長λの２分の１以下の間隔で配置した平行平板導体間に、高周波ダイオード発振器が一端部に付設され、前記高周波ダイオード発振器から出力されたミリ波信号を伝搬させる第１の誘電体線路と、バイアス電圧印加方向が前記ミリ波信号の電界方向に合致するように配置され、前記バイアス電圧を周期的に制御することによって前記ミリ波信号を周波数変調した送信用のミリ波信号として出力する可変容量ダイオードと、前記第１の誘電体線路に、一端側が電磁結合するように近接配置されるかまたは一端が接合されて、前記送信用のミリ波信号の一部をミキサー側へ伝搬させる第２の誘電体線路と、前記平行平板導体に平行に配設されたフェライト板の周縁部に所定間隔で配置され、かつそれぞれ前記ミリ波信号の入出力端とされた第１の接続部，第２の接続部および第３の接続部を有し、一つの接続部から入力された前記ミリ波信号を前記フェライト板の面内で時計回りまたは反時計回りに隣接する他の接続部より出力するサーキュレータであって、前記第１の誘電体線路の前記ミリ波信号の出力端に前記第１の接続部が接合されるサーキュレータと、該サーキュレータの前記第２の接続部に接合され、前記送信用のミリ波信号を伝搬させるとともに先端部に送受信アンテナを有する第３の誘電体線路と、前記送受信アンテナで受信され前記第３の誘電体線路を伝搬して前記サーキュレータの前記第３の接続部より出力した受信波をミキサー側へ伝搬させる第４の誘電体線路と、前記第２の誘電体線路の中途と前記第４の誘電体線路の中途とを近接させて電磁結合させるかまたは接合させて成り、前記送信用のミリ波信号の一部と前記受信波とを混合して中間周波信号を発生するミキサー部と、を設けたミリ波送受信器において、前記第１〜第４の誘電体線路のうち少なくとも一つが、複数の誘電体線路部分からなり、前記平行平板導体とともに本発明の非放射性誘電体線路を構成することを特徴とする。
【００１５】
本発明のミリ波送受信器は、上記の構成により、信頼性が高く、高性能かつ小型のミリ波送受信器とすることができる。また、高周波ダイオードの発振周波数を制御したり、ミリ波信号の分岐強度や合波混合の度合い等を制御でき、ミリ波送受信器の伝送特性を最も良好な状態に調整したり、異なる周波数帯域で使用可能なように調整することができる。
【００１６】
また本発明のミリ波送受信器は、ミリ波信号の波長λの２分の１以下の間隔で配置した平行平板導体間に、高周波ダイオード発振器が一端部に付設され、前記高周波ダイオード発振器から出力されたミリ波信号を伝搬させる第１の誘電体線路と、バイアス電圧印加方向が前記ミリ波信号の電界方向に合致するように配置され、前記バイアス電圧を周期的に制御することによって前記ミリ波信号を周波数変調した送信用のミリ波信号として出力する可変容量ダイオードと、前記第１の誘電体線路に、一端側が電磁結合するように近接配置されるかまたは一端が接合されて、前記送信用のミリ波信号の一部をミキサー側へ伝搬させる第２の誘電体線路と、前記平行平板導体に平行に配設されたフェライト板の周縁部に所定間隔で配置され、かつそれぞれ前記ミリ波信号の入出力端とされた第１の接続部，第２の接続部および第３の接続部を有し、一つの接続部から入力された前記ミリ波信号を前記フェライト板の面内で時計回りまたは反時計回りに隣接する他の接続部より出力するサーキュレータであって、前記第１の誘電体線路の前記ミリ波信号の出力端に前記第１の接続部が接続されるサーキュレータと、該サーキュレータの前記第２の接続部に接続され、前記送信用のミリ波信号を伝搬させるとともに先端部に送信アンテナを有する第３の誘電体線路と、先端部に受信アンテナ、他端部にミキサーが各々設けられた第４の誘電体線路と、前記サーキュレータの前記第３の接続部に接続され、前記送信アンテナで受信混入したミリ波信号を伝搬させるとともに先端部に設けられた無反射終端部で前記受信混入したミリ波信号を減衰させる第５の誘電体線路と、前記第２の誘電体線路の中途と前記第４の誘電体線路の中途とを近接させて電磁結合させるかまたは接合させて成り、前記送信用のミリ波信号の一部と受信波とを混合して中間周波信号を発生するミキサー部と、を設けたミリ波送受信器において、前記第１〜５の誘電体線路のうち少なくとも一つが、複数の誘電体線路部分からなり、前記平行平板導体とともに請求項１記載の非放射性誘電体線路を構成することを特徴とする。
【００１７】
本発明のミリ波送受信器は、上記の構成により、信頼性が高く、高性能かつ小型のミリ波送受信器とすることができる。また、高周波ダイオードの発振周波数を制御したり、ミリ波信号の分岐強度や合波混合の度合い等を制御でき、ミリ波送受信器の伝送特性を最も良好な状態に調整したり、異なる周波数帯域で使用可能なように調整することができる。さらに、送信用のミリ波信号がサーキュレータを介してミキサーへ混入することがなく、その結果、受信信号のノイズが低減し、ミリ波レーダーに適用した場合に探知距離が増大し、ミリ波信号の伝送特性に優れたものとなる。
【００１８】
【発明の実施の形態】
本発明のＮＲＤガイドについて以下に詳細に説明する。図１は本発明のＮＲＤガイドの斜視図であり、同図において１，３は伝搬させる高周波信号の波長λの２分の１以下の間隔で配置した下側、上側の平行平板導体、２は誘電体線路であり、複数の誘電体線路部分２ａ，２ｂの端面同士を対向させて構成されているとともに、誘電体線路部分２ａ，２ｂが隣接する誘電体線路部分２ａ，２ｂに対して高周波信号の伝送方向に直交し、かつ平行平板導体１，３の内面に平行な方向にλ／８以下の距離Ｌを移動可能に設置されている。なお、距離Ｌが０の場合は、誘電体線路部分２ａ，２ｂの対向するそれらの端面の中心点が一致した状態に相当する。
【００２０】
誘電体線路部分２ａ，２ｂを移動させる手段としては、誘電体線路部分２ａ，２ｂを設置する平行平板導体１，３の部位に、誘電体線路部分２ａ，２ｂの幅よりも最大λ／４程度幅広な溝で、誘電体線路部分２ａ，２ｂ全体を嵌め込むことができるような溝を形成し、その溝内で誘電体線路部分２ａ，２ｂの設置位置を調整する構成とし得る。この場合、溝の幅を誘電体線路部分２ａ，２ｂの幅よりも最大λ／４程度幅広とするのは、誘電体線路部分２ａ，２ｂの高周波信号の伝送方向に直交し、かつ平行平板導体１，３の内面に平行な方向は左右の２方向あり、１方向でλ／８とし、その反対方向にもλ／８移動可能とすれば、λ／４となるからである。また、最小でλ／１６としてもよく、その場合は、一方の誘電体線路部分２ａ，２ｂを左右のいずれかの方向にλ／１６移動させ、他方の誘電体線路部分２ａ，２ｂを反対方向にλ／１６移動させればよい。
【００２１】
なお、距離Ｌの移動後の誘電体線路部分２ａ，２ｂは、接着剤等で固定することもできる。また、誘電体線路部分２ａ，２ｂの移動については、上記のような移動機構を使用せずに手動で調整してもよい。その場合、平行平板導体１，３の内面に、誘電体線路部分２ａ，２ｂの位置調整のためのスケール目盛を、微小な深さの溝で刻んだり、印刷法等で形成することもできる。
【００２２】
これらの誘電体線路部分２ａ，２ｂの端面は高周波信号の伝送方向に略垂直であればよく、完全な垂直でなくともよい。また、その端面は平面状でなくともよく、ある程度の曲面状とされていても構わない。さらには、端面同士の間隔が波長λの１／８以下であれば直接接していなくともよい。
【００２３】
なお、高周波信号の波長λは、使用周波数における高周波信号の空気中での波長に相当する。
【００２４】
本発明のＮＲＤガイドＳ用の平行平板導体１，３は、高い電気伝導度および加工性等の点で、Ｃｕ，Ａｌ，Ｆｅ，ＳＵＳ（ステンレススチール），Ａｇ，Ａｕ，Ｐｔ等からなり、鍛造，鋳造，ダイカスト，研削等で加工された金属板、あるいはセラミックス，樹脂等から成る絶縁板の表面にこれらの導体層を形成したものでもよい。
【００２５】
本発明のＮＲＤガイドＳの誘電体線路２は、使用周波数６０ＧＨｚでのＱ値が１０００以上である、Ｍｇ，Ａｌ，Ｓｉの複合酸化物を主成分としたセラミックスを用いるのがよい。このセラミックスは比誘電率が４．５〜８程度である。比誘電率をこの範囲に限定したのは、比誘電率が４．５未満の場合には、上記したようにＬＳＭモードの電磁波のＬＳＥモードへの変換が大きくなるからである。また、比誘電率が８を超えると、５０ＧＨｚ以上の周波数で使用する際に誘電体線路２の幅を非常に細くしなければならず、加工が困難になって形状精度が劣化し、強度の点でも問題が生じる。
【００２６】
また本発明において、一連の誘電体線路２を構成する誘電体線路部分２ａ，２ｂのズレの距離Ｌはλ／８以下とする。λ／８よりも大きくすると、高周波信号の伝送損失が大きくなるからである。誘電体線路部分２ａ，２ｂの個数が増加したり、さらなる低伝送損失を求める場合には、距離Ｌをλ／８以下のより小さい値にすることが好ましい。距離Ｌをほとんど０にすれば、高周波信号の伝送損失が最も小さくなる。
【００２７】
また、使用周波数６０ＧＨｚでのＱ値が１０００以上である、Ｍｇ，Ａｌ，Ｓｉの複合酸化物を主成分としたセラミックスの場合、これは、近年におけるマイクロ波帯域，ミリ波帯に含まれる６０ＧＨｚで使用される誘電体線路として、十分な低損失性を実現するものである。
【００２８】
そして、誘電体線路２の組成および組成比は、モル比組成式をｘＭｇＯ・ｙＡｌ_２Ｏ_３・ｚＳｉＯ_２と表したときに、ｘ＝１０〜４０モル％，ｙ＝１０〜４０モル％，ｚ＝２０〜８０モル％，ｘ＋ｙ＋ｚ＝１００モル％を満足する、Ｍｇ，Ａｌ，Ｓｉの複合酸化物を主成分とするものがよい。
【００２９】
本発明のＮＲＤガイドＳの誘電体線路２の材料であるセラミックス（誘電体磁器組成物）の主成分の組成比を上記範囲に限定したのは、次の理由による。即ち、ｘを１０〜４０モル％としたのは、１０モル％未満では良好な焼結体が得られず、また４０モル％を超えると比誘電率が大きくなるからである。特にｘは、６０ＧＨｚでのＱ値を２０００以上とするという点から１５〜３５モル％が好ましい。
【００３０】
また、ｙを１０〜４０モル％としたのは、ｙが１０モル％よりも小さい場合には良好な焼結体が得られず、４０モル％を超えると比誘電率が大きくなるからである。ｙは、６０ＧＨｚでのＱ値を２０００以上とするという点から１７〜３５モル％が好ましい。
【００３１】
ｚを２０〜８０モル％としたのは、ｚが２０モル％よりも小さい場合には比誘電率が大きくなり、８０モル％を超えると良好な焼結体が得られずＱ値が低下するからである。ｚは、６０ＧＨｚでのＱ値を２０００以上とするという点から３０〜６５モル％が好ましい。
【００３２】
これらＭｇＯ，Ａｌ_２Ｏ_３，ＳｉＯ_２のモル％を示すｘ，ｙ，ｚは、ＥＰＭＡ（ＥｌｅｃｔｒｏｎＰｒｏｂｅＭｉｃｒｏＡｎａｌｙｓｉｓ）法，ＸＲＤ（Ｘ−ｒａｙＤｉｆｆｒａｃｔｉｏｎ：Ｘ線回折）法等の分析方法で特定できる。
【００３３】
また、本発明のＮＲＤガイドＳの誘電体線路２用のセラミックス（誘電体磁器組成物）は、主結晶相がコーディエライト（２ＭｇＯ・２Ａｌ_２Ｏ_３・５ＳｉＯ_２）であり、他の結晶相としてムライト（３Ａｌ_２Ｏ_３・２ＳｉＯ_２），スピネル（ＭｇＯ・Ａｌ_２Ｏ_３），プロトエンスタタイト｛メタ珪酸マグネシウム（ＭｇＯ・ＳｉＯ_２）を主成分とするステアタイトの一種｝，クリノエンスタタイト｛メタ珪酸マグネシウム（ＭｇＯ・ＳｉＯ_２）を主成分とするステアタイトの一種｝，フォルステライト（２ＭｇＯ・ＳｉＯ_２），クリストバライト｛珪酸（ＳｉＯ₂）の一種｝，トリジマイト｛珪酸（ＳｉＯ_２）の一種｝，サファリン（Ｍｇ，Ａｌの珪酸塩の一種）等が析出する場合があるが、組成によってその析出相が異なる。なお、本発明の誘電体磁器組成物ではコーディエライトのみからなる結晶相であってもよい。
【００３４】
本発明のＮＲＤガイドＳの誘電体線路２用の誘電体磁器組成物は、以下のようにして製造する。原料粉末として、例えばＭｇＣＯ_３粉末，Ａｌ_２Ｏ_３粉末，ＳｉＯ_２粉末を用い、これらを所定割合で秤量し、湿式混合した後乾燥し、この混合物を大気中において１１００〜１３００℃で仮焼した後、粉砕し粉末状とする。得られた粉末に適量の樹脂バインダを加えて成形し、この成形体を大気中１３００〜１４５０℃で焼成することにより得られる。
【００３５】
原料粉末中に含まれるＭｇ，Ａｌ，Ｓｉの元素から成る原料粉末は、それぞれ酸化物，炭酸塩，酢酸塩等の無機化合物、もしくは有機金属等の有機化合物のいずれであってもよく、焼成により酸化物となるものであればよい。
【００３６】
なお、本発明のＮＲＤガイドＳの誘電体線路２の誘電体磁器組成物の主成分は、Ｍｇ，Ａｌ，Ｓｉの複合酸化物を主成分とし、６０ＧＨｚでのＱ値を１０００以上であるという特性を損なわない範囲で、上記元素以外に、粉砕ボールや原料粉末の不純物が混入したりしてもよく、焼結温度範囲の制御、機械的特性向上を目的に他の成分を含有させてもよい。例えば、希土類元素化合物、Ｂａ，Ｓｒ，Ｃａ，Ｎｉ，Ｃｏ，Ｉｎ，Ｇａ，Ｔｉ等の酸化物、ならびに窒化ケイ素等の窒化物などの非酸化物である。これらは単独または複数種が含まれていてもよい。
【００３７】
本発明でいう高周波帯域は、数１０〜数１００ＧＨｚ帯域のマイクロ波帯域およびミリ波帯域に相当し、例えば３０ＧＨｚ以上、特に５０ＧＨｚ以上、更には７０ＧＨｚ以上の高周波帯域が好適である。
【００３８】
さらに、誘電体線路２のその他の材料として、テフロン，ポリスチレン，ガラスエポキシ樹脂等の樹脂系のもの、アルミナセラミックス，ガラスセラミックス，フォルステライトセラミックス等のものでもよいが、誘電特性、加工性、強度、小型化、信頼性等の点でコーディエライトセラミックスが好ましい。
【００３９】
本発明のＮＲＤガイドＳは、無線ＬＡＮ，自動車のミリ波レーダ等に使用されるものであり、例えば自動車の周囲の障害物および他の自動車に対しミリ波を照射し、反射波を元のミリ波と合成して中間周波信号を得て、この中間周波信号を分析することにより障害物及び他の自動車までの距離、それらの移動速度等が測定できる。
【００４０】
かくして、本発明によれば、信頼性が高く、高性能で小型なＮＲＤガイドを構成することができる。また、高周波信号の伝送特性を維持した状態で、誘電体線路部分と電磁結合している、高周波ダイオード等の他の部品や他の誘電体線路との間隔を制御できる。これにより、高周波ダイオードの発振周波数を制御したり、他の誘電体線路とのカップリングの度合い等を制御できる。また、好ましくは、従来のアルミナセラミックス等よりも低比誘電率のセラミックスからなる誘電体線路を用いているため、ＬＳＭモードの電磁波のＬＳＥモードへの変換を少なくでき、高周波信号の損失が抑えられる。
【００４１】
本発明のＮＲＤガイドを用いたミリ波送受信器について、以下に説明する。図４，図５は本発明のミリ波送受信器としてのミリ波レーダーを示すものであり、図４は送信アンテナと受信アンテナが一体化されたものの平面図、図５は送信アンテナと受信アンテナが独立したものの平面図である。
【００４２】
図４において、５１は一方の平行平板導体（他方は省略する）、５２は第１の誘電体線路５３の一端に設けられた、高周波ダイオード発振器を有する電圧制御型のミリ波信号発振部（電圧制御発振部）であり、バイアス電圧印加方向が高周波信号の電界方向に合致するように、第１の誘電体線路５３の高周波ダイオード近傍に配置された可変容量ダイオードのバイアス電圧を周期的に制御して、三角波，正弦波等とすることにより、周波数変調した送信用のミリ波信号として出力する。
【００４３】
５３は、高周波ダイオード発振器が一端部に付設され、高周波ダイオード発振器から出力されたミリ波信号が変調された送信用のミリ波信号を伝搬させる第１の誘電体線路、５４は、第１，第３，第４の誘電体線路５３，５５，５７にそれぞれ結合される第１，第２，第３の接続部５４ａ，５４ｂ，５４ｃを有する、フェライト円板等から成るサーキュレータ、５５は、サーキュレータ５４の第２の接続部５４ｂに接続され、ミリ波信号を伝搬させるとともに先端部に送受信アンテナ５６を有する第３の誘電体線路、５６は、第３の誘電体線路５５の先端をテーパー状等とすることにより構成された送受信アンテナである。
【００４４】
なお、送受信アンテナ５６は、平行平板導体５１に形成された貫通孔を通して高周波信号を入出力させ、平行平板導体５１の外面に貫通孔に接続された金属導波管を介して設置されたホーンアンテナ等であってもよい。
【００４５】
また５７は、送受信アンテナ５６で受信され第３の誘電体線路５５を伝搬してサーキュレータ５４の第３の接続部５４ｃより出力した受信波をミキサー５９側へ伝搬させる第４の誘電体線路、５８は、第１の誘電体線路５３に一端側が電磁結合するように近接配置されて、送信用のミリ波信号の一部をミキサー５９側へ伝搬させる第２の誘電体線路、５８ａは、第２の誘電体線路５８のミキサー５９と反対側の一端部に設けられた無反射終端部（ターミネータ）である。また、図中Ｍ１は、第２の誘電体線路５８の中途と第４の誘電体線路５７の中途とを近接させて電磁結合させることにより、送信用のミリ波信号の一部と受信波を混合させて中間周波信号を発生させるミキサー部である。
【００４６】
本発明のミリ波送受信器のサーキュレータ５４は、平行平板導体５１，５１間に平行に配設された一対のフェライト円板の周縁部に所定間隔、例えばフェライト円板の中心点に関して角度で１２０°間隔で配置され、かつそれぞれミリ波信号の入出力端とされた第１の接続部５４ａ，第２の接続部５４ｂおよび第３の接続部５４ｃを有し、一つの接続部から入力されたミリ波信号をフェライト円板の面内で時計回りまたは反時計回りに隣接する他の接続部より出力するものである。また、平行平板導体５１の外側主面のフェライト円板に対向する部位には、フェライト円板を伝搬する電磁波の波面を回転させるための磁石が、磁力線がフェライト円板に対し略垂直方向（略上下方向）に通過するように設けられる。なお、このフェライト板は円板状のものに限らず、多角形状等のものでもよい。
【００４７】
また、本発明のミリ波送受信器の他の実施形態として、送信アンテナと受信アンテナを独立させた図５のタイプがある。同図において、６１は一方の平行平板導体（他方は省略する）、６２は第１の誘電体線路６３の一端に設けられた、高周波ダイオード発振器を有する電圧制御型のミリ波信号発振部であり、バイアス電圧印加方向が高周波信号の電界方向に合致するように第１の誘電体線路６３の高周波ダイオード近傍に配置された可変容量ダイオードのバイアス電圧を周期的に制御して、三角波，正弦波等とすることにより、周波数変調した送信用のミリ波信号として出力する。
【００４８】
６３は、高周波ダイオード発振器が一端部に付設され、高周波ダイオード発振器から出力されたミリ波信号が変調された送信用のミリ波信号を伝搬させる第１の誘電体線路、６４は、第１，第３，第５の誘電体線路６３，６５，６７にそれぞれ接続される第１，第２，第３の接続部（図３と同様であり図示せず）を有する、フェライト円板等から成るサーキュレータ、６５は、サーキュレータ６４の第２の接続部に接続され、ミリ波信号を伝搬させるとともに先端部に送信アンテナ６６を有する第３の誘電体線路、６６は、第３の誘電体線路６５の先端をテーパー状等とすることにより構成された送信アンテナ、６７は、サーキュレータ６４の第３の接続部に接続され、送信用のミリ波信号を減衰させる無反射終端部６７ａが先端に設けられた第５の誘電体線路である。
【００４９】
また６８は、第１の誘電体線路６３に一端側が電磁結合するように近接配置されて、送信用のミリ波信号の一部をミキサー７１側へ伝搬させる第２の誘電体線路、６８ａは、第２の誘電体線路６８のミキサー７１と反対側の一端部に設けられた無反射終端部、６９は、受信アンテナ７０で受信された受信波をミキサー７１側へ伝搬させる第４の誘電体線路である。また、図中Ｍ２は、第２の誘電体線路６８の中途と第４の誘電体線路６９の中途とを近接させて電磁結合させることにより、送信用のミリ波信号の一部と受信波とを混合させて中間周波信号を発生させるミキサー部である。
【００５０】
なお、送信アンテナ６６および受信アンテナ７０は、平行平板導体６１に形成された貫通孔を通して高周波信号を入力または出力させ、平行平板導体６１の外面に貫通孔に接続された金属導波管を介して設置されたホーンアンテナ等であってもよい。
【００５１】
本発明のミリ波送受信器では、図４において、第１の誘電体線路５３に第２の誘電体線路５８の一端側を近接配置するかまたは一端部を接合するが、接合する場合には、接合部において、第１の誘電体線路５３を直線状、第２の誘電体線路５８を円弧状となし、その円弧状部の曲率半径ｒを高周波信号の波長λ以上とする。これにより、高周波信号を損失を小さくして均等の出力で分岐させ得る。また、接合部において、第２の誘電体線路５８を直線状、第１の誘電体線路５３を円弧状となし、その円弧状部の曲率半径ｒを高周波信号の波長λ以上としてもよく、この場合も上記と同様の効果が得られる。
【００５２】
また、ミキサー５９部において、第２の誘電体線路５８と第４の誘電体線路５７とを接合することもできる。この場合は、上記と同様に、これらの誘電体線路５８，５７のいずれか一方の接合部を円弧状となし、その円弧状部の曲率半径ｒを高周波信号の波長λ以上とするのがよい。また、第２の誘電体線路５８と第４の誘電体線路５７とを電磁結合するように近接配置する場合は、その近接部において、第２の誘電体線路５８と第４の誘電体線路５７との近接部の少なくとも一方を円弧状とすることにより、近接配置の構成とすることができる。
【００５３】
また好ましくは、上記の接合部の曲率半径ｒは３λ以下がよく、３λを超えると接合構造が大きくなり小型化のメリットが得られない。接合部の曲率半径ｒを波長λより小さく設定すると、円弧状の接合部を有する誘電体線路への分岐強度は小さくなる。
【００５４】
このような第１の誘電体線路５３と第２の誘電体線路５８との接合構造、および第２の誘電体線路５８と第４の誘電体線路５７との接合構造、並びに第２の誘電体線路５８と第４の誘電体線路５７との近接配置の構成については、図４の場合も上記と同様である。
【００５５】
そして、これらの各種部品は、ミリ波信号の波長λの２分の１以下の間隔で配置した平行平板導体間に設けられる。
【００５６】
図４のものにおいて、第１の誘電体線路５３の中途にスイッチを設け、それをオン−オフ（ＯＮ−ＯＦＦ）することでパルス変調制御することもできる。例えば、図７に示すような、配線基板８８の一主面に第２のチョーク型バイアス供給線路１１２を形成し、その中途に半田実装されたビームリードタイプのＰＩＮダイオードやショットキーバリアダイオードを設けたスイッチである。なお、図７においてＥは誘電体線路７７内を伝搬する高周波信号の電界方向を示し、１１１はＰＩＮダイオード，ショットキーバリアダイオード等のパルス変調用ダイオードを接続するための接続パッドである。
【００５７】
この配線基板８８を、第１の誘電体線路５３の第２の誘電体線路５８との信号分岐部とサーキュレータ５４との間に、ＰＩＮダイオードやショットキーバリアダイオードのパルス変調用ダイオードのバイアス電圧印加方向がＬＳＭモードの高周波信号の電界方向に合致するように配置し、第１の誘電体線路５３に介在させるものである。また、第１の誘電体線路５３にもう一つのサーキュレータを介在させ、その第１，第３の接続部に第１の誘電体線路５３を接続し、第２の接続部に他の誘電体線路を接続し、その誘電体線路の先端部の端面に、図７のような構成でショットキーバリアダイオードを設けたスイッチを設置してもよい。
【００５８】
図５のものにおいて、サーキュレータ６４をなくし、第１の誘電体線路６３の先端部に送信アンテナ６６を接続した構成とすることもできる。この場合、小型化されたものとなるが、受信波の一部が電圧制御発振部（ミリ波信号発振部）６２に混入しノイズ等の原因となり易いため、図５のタイプが好ましい。
【００５９】
また、図５のタイプにおいて、第２の誘電体線路６８は、第３の誘電体線路６５に一端側が電磁結合するように近接配置されるか第３の誘電体線路６５に一端が接合されて、送信用のミリ波信号の一部をミキサー７１側へ伝搬させるように配置されていてもよい。この構成においても、図５のものと同様の機能および作用効果を有する。
【００６０】
図５のものにおいて、第１の誘電体線路６３の中途に、図７のものと同様に構成したスイッチを設け、それをオン−オフすることでパルス変調制御することもできる。例えば、図７のような、配線基板８８の一主面に第２のチョーク型バイアス供給線路１１２を形成し、その中途に半田実装されたビームリードタイプのＰＩＮダイオードやショットキーバリアダイオードを設けたスイッチである。この配線基板８８を、第１の誘電体線路６３の第２の誘電体線路６８との信号分岐部と、サーキュレータ６４との間に、ＰＩＮダイオードやショットキーバリアダイオードのバイアス電圧印加方向がＬＳＭモードの高周波信号の電界方向に合致するように配置し、第１の誘電体線路６３に介在させるものである。
【００６１】
また、第１の誘電体線路６３にもう一つのサーキュレータを介在させ、その第１，第３の接続部に第１の誘電体線路６３を接続し、第２の接続部に他の誘電体線路を接続し、その誘電体線路の先端部の端面に、図７のような構成のショットキーバリアダイオードを設けたスイッチを設置してもよい。
【００６２】
また、これらのミリ波送受信器において、平行平板導体間の間隔は、ミリ波信号の空気中での波長であって、使用周波数での波長λの２分の１以下となる。
【００６３】
また、図４，図５のミリ波送受信器はＦＭＣＷ（Frequency Modulation Continuous Waves）方式であり、ＦＭＣＷ方式の動作原理は以下のようなものである。電圧制御発振部の変調信号入力用のＭＯＤＩＮ端子に、電圧振幅の時間変化が三角波等となる入力信号を入力し、その出力信号を周波数変調し、電圧制御発振部の出力周波数偏移を三角波等になるように偏移させる。そして、送受信アンテナ５６，送信アンテナ６６より出力信号（送信波）を放射した場合、送受信用アンテナ５６，送信アンテナ６６の前方にターゲットが存在すると、電波の伝搬速度の往復分の時間差をともなって、反射波（受信波）が戻ってくる。この時、ミキサー５９，７１の出力側のＩＦＯＵＴ端子には、送信波と受信波の周波数差が出力される。
【００６４】
このＩＦＯＵＴ端子の出力周波数等の周波数成分を解析することで、Ｆif＝４Ｒ・ｆｍ・Δｆ／ｃ｛Fif：ＩＦ（Intermediate Frequency）出力周波数，Ｒ：距離，ｆｍ：変調周波数，Δｆ：周波数偏移幅，ｃ：光速｝という関係式から距離を求めることができる。
【００６５】
このように、自動車のミリ波レーダ等に適用した場合、自動車の周囲の障害物および他の自動車に対しミリ波を照射し、反射波を元のミリ波と合成して中間周波信号を得て、この中間周波信号を分析することにより障害物および他の自動車までの距離、それらの移動速度等が測定できる。
【００６６】
本発明のミリ波送受信器における高周波ダイオード発振器を用いた電圧制御発振部５２，６２について以下に説明する。図６，図７は本発明のミリ波送受信器におけるＮＲＤガイド型の高周波ダイオード発振器を示し、これらの図において、７１は一対の平行平板導体、７２はガンダイオード７３を設置（マウント）するための略直方体状の金属ブロック等の金属部材、７３はマイクロ波，ミリ波を発振する高周波ダイオードの１種であるガンダイオード、７４は金属部材７２の一側面に設置され、ガンダイオード７３にバイアス電圧を供給するとともに高周波信号の漏れを防ぐローパスフィルタとして機能するチョーク型バイアス供給線路７４ａを形成した配線基板、７５はチョーク型バイアス供給線路７４ａとガンダイオード７３の上部導体とを接続する金属箔リボン等の帯状導体、７７はガンダイオード７３の近傍に配置され高周波信号を受信し外部へ伝搬させる誘電体線路（第１の誘電体線路５３，６３に相当するもの）である。
【００６７】
また図６において、チョーク型バイアス供給線路７４ａは、幅の広い線路および幅の狭い線路の長さがそれぞれ略λ／４であり、また帯状導体７５の長さは略｛（３／４）＋ｍ｝λ（ｍは０以上の整数）である。この帯状導体７５の長さは略３λ／４〜略｛（３／４）＋３｝λがよく、略｛（３／４）＋３｝λを超えると帯状導体７５が長くなり、撓み、捩じれ等が生じ易くなり、個々の高周波ダイオード発振器間で発振周波数等の特性のばらつきが大きくなるとともに、種々の共振モードが発生して、所望の発振周波数と異なる周波数の信号が発生するという問題が生じる。より好ましくは、略３λ／４，略｛（３／４）＋１｝λである。
【００６８】
また、略｛（３／４）＋ｍ｝λとしたのは、｛（３／４）＋ｍ｝λから多少ずれていても共振は可能だからである。例えば、帯状導体７５を｛（３／４）＋ｍ｝λよりも１０〜２０％程度長く形成してもよく、その場合、帯状導体７５の接するチョーク型バイアス供給線路７４ａの１パターン目の長さλ／４のうち一部が共振に寄与すると考えられるからである。従って、帯状導体７５の長さは｛（３／４）＋ｍ｝λ±２０％程度の範囲内で変化させることができる。
【００６９】
これらチョーク型バイアス供給線路７４ａおよび帯状導体７５の材料は、Ｃｕ，Ａｌ，Ａｕ，Ａｇ，Ｗ，Ｔｉ，Ｎｉ，Ｃｒ，Ｐｄ，Ｐｔ等から成り、特にＣｕ，Ａｇが、電気伝導度が良好であり、損失が小さく、発振出力が大きくなるといった点で好ましい。
【００７０】
また、帯状導体７５は金属部材７２の表面から所定間隔をあけて金属部材７２と電磁結合しており、チョーク型バイアス供給線路７４ａとガンダイオード７３間に架け渡されている。即ち、帯状導体７５の一端はチョーク型バイアス供給線路７４ａの一端に半田付け等により接続され、帯状導体７５の他端はガンダイオード７３の上部導体に半田付け等により接続されており、帯状導体７５の接続部を除く中途部分は宙に浮いた状態となっている。
【００７１】
そして、金属部材７２は、ガンダイオード７３の電気的な接地（アース）を兼ねているため金属導体であればよく、その材料は金属（合金を含む）導体であれば特に限定するものではなく、真鍮（黄銅：Ｃｕ−Ｚｎ合金），Ａｌ，Ｃｕ，ＳＵＳ（ステンレススチール），Ａｇ，Ａｕ，Ｐｔ等から成る。また金属部材７２は、全体が金属から成る金属ブロック、セラミックスやプラスチック等の絶縁基体の表面全体または部分的に金属メッキしたもの、絶縁基体の表面全体または部分的に導電性樹脂材料等をコートしたものであってもよい。
【００７２】
また、誘電体線路７７は、図４，図５の第１の誘電体線路５３，６３に相当するものであり、その材料は上記の通りコーディエライト（２ＭｇＯ・２Ａｌ_２Ｏ_３・５ＳｉＯ_２）セラミックス（比誘電率４〜５）等が好ましく、これらは高周波帯域において低損失である。ガンダイオード７３と誘電体線路７７との間隔は１．０ｍｍ程度以下が好ましく、１．０ｍｍを超えると損失を小さくして電磁的結合が可能な最大離間幅を超える。
【００７３】
また、本発明の高周波ダイオードとしては、インパット（impatt：impact ionisation avalanche transit time）・ダイオード，トラパット（trapatt：trapped plasma avalanche triggered transit）・ダイオード，ガンダイオード等のマイクロ波ダイオードおよびミリ波ダイオードが好適に使用される。
【００７４】
図７のスイッチは、バラクタダイオード等の可変容量ダイオードから成る周波数変調用ダイオード１１０を設けたものであり、配線基板８８の一主面に第２のチョーク型バイアス供給線路１１２を形成し、その中途に半田実装された周波数変調用ダイオード１１０を設けたスイッチである。周波数変調用ダイオード１１０に印加するバイアス電圧を制御することによりガンダイオード７３の発振周波数を制御することができる。なお、図７においてＥは誘電体線路７７内を伝搬する高周波信号の電界方向を示し、１１１は周波数変調用ダイオード１１０を接続するための接続パッドである。
【００７５】
【実施例】
本発明の実施例を以下に示す。
【００７６】
（実施例）
図１のＮＲＤガイドＳを以下のように構成した。誘電体線路２の材料として、Ｍｇ，Ａｌ，Ｓｉの複合酸化物を主成分としたセラミックスであって、種々の組成比としたものを作製した。それらの比誘電率と周波数６０ＧＨｚにおけるＱ値を表１に示す。
【００７７】
【表１】

【００７８】
一対の平行平板導体１，３として、アルミニウムから成る縦８０ｍｍ×横８０ｍｍ×厚さ２ｍｍの金属板を１．８ｍｍの間隔ｄで配置し、表１のＮＯ．２４のコーディエライトセラミックスからなる誘電体線路２を介装した。この誘電体線路２の断面形状は、高さが約１．８ｍｍ、幅が０．８ｍｍの長方形状であり、２つの誘電体線路部分２ａ，２ｂを距離Ｌずらして配置したものである。このＮＲＤガイドＳについて、周波数特性を測定した結果を図８に示す。同図は、周波数７７ＧＨｚにおけるズレ（距離Ｌ）と伝送損失（｜Ｓ２１｜）との関係を示すものであり、誘電体線路部分２ａ，２ｂの距離Ｌがλ／８以下の場合、誘電体線路２による挿入損失が１ｄＢ以下となった。
【００７９】
なお、本発明は上記実施例に限定されるものではなく、本発明の要旨を逸脱しない範囲内で種々の変更を行うことは何等差し支えない。
【００８０】
【発明の効果】
本発明のＮＲＤガイドによれば、誘電体線路は、複数の誘電体線路部分の端面同士を対向させて構成されているとともに、誘電体線路部分を設置する平行平板導体の部位に誘電体線路部分の幅よりも幅広な溝で誘電体線路部分全体を嵌め込むことができるような溝を形成し、その溝内で誘電体線路部分の設置位置を調整することによって、誘電体線路部分が隣接するものに対してその端面同士が高周波信号の伝送方向に直交し、かつ平行平板導体の内面に平行な方向にλ／８以下の距離を移動可能に設置されていることにより、ＬＳＭモードの電磁波のＬＳＥモードへの変換を少なくすることができ、また、直線部と曲線部からなる複雑形状の誘電体線路を容易に作製することができる。さらに、誘電体線路に急峻な曲線部を設けて小型化できるので、全体を小型化できる。そして、樹脂材料で誘電体線路の支持用ジグや回路基板等を作製し、誘電体線路近傍に配置しても、その影響を受けにくくなる。
【００８１】
また、直線部からなる誘電体線路の組み合わせでも、曲線でなければ描けなかった形状の線路を、接合端面の形状を変更することなく、断続的な直線部の組み合わせで作製することができる。
【００８２】
また、高周波信号の伝送特性を維持した状態で、誘電体線路部分と電磁結合している、高周波ダイオード等の他の部品や他の誘電体線路との間隔を制御できる。これにより、高周波ダイオードの発振周波数を制御したり、他の誘電体線路とのカップリングの度合い等を制御できる。
【００８３】
また好ましくは、誘電体線路は、Ｍｇ，Ａｌ，Ｓｉの複合酸化物を主成分とするセラミックスからなるとともに測定周波数６０ＧＨｚでのＱ値が１０００以上であることにより、従来のアルミナセラミックス等よりも低比誘電率のセラミックスからなる誘電体線路を用いることにより、ＬＳＭモードの電磁波のＬＳＥモードへの変換を少なくでき、高周波信号の損失が抑えられる。
【００８４】
また好ましくは、複合酸化物のモル比組成式がｘＭｇＯ・ｙＡｌ_２Ｏ_３・ｚＳｉＯ_２（但し、ｘ＝１０〜４０モル％，ｙ＝１０〜４０モル％，ｚ＝２０〜８０モル％，ｘ＋ｙ＋ｚ＝１００モル％を満足する）で表されることにより、さらに伝送損失が少なく、かつ安価で高い形状精度の誘電体線路を用いたＮＲＤガイドを作製できる。
【００８５】
本発明のミリ波送受信器は、送受信アンテナを備えたタイプ、および送信アンテナと受信アンテナとが独立したタイプにおいて、各誘電体線路のうち少なくとも一つが、複数の誘電体線路部分からなり、平行平板導体とともに上記本発明の非放射性誘電体線路を構成することにより、誘電体線路を伝搬するＬＳＭモードの電磁波のＬＳＥモードへの変換が少なく、従って誘電体線路に小さい曲率半径で使用周波数範囲が広い急峻な曲線部を作製することができ、その結果、ミリ波送受信器を使用周波数範囲が広く、小型化でき、しかも加工が容易で作製の自由度の高いものとすることができる。
【００８６】
また、高周波ダイオードの発振周波数を制御したり、ミリ波信号の分岐強度や合波混合の度合い等を制御でき、ミリ波送受信器の伝送特性を最も良好な状態に調整したり、異なる周波数帯域で使用可能なように調整することができる。
【００８７】
さらに、送信アンテナと受信アンテナとが独立したタイプでは、送信用のミリ波信号がサーキュレータを介してミキサーへ混入することがなく、その結果、受信信号のノイズが低減し探知距離が増大し、さらにミリ波信号の伝送特性に優れたものとなる。
【図面の簡単な説明】
【図１】本発明のＮＲＤガイドの内部を透視した斜視図である。
【図２】従来のＮＲＤガイドの内部を透視した斜視図である。
【図３】従来の他のＮＲＤガイドの内部を透視した斜視図である。
【図４】本発明のＮＲＤガイドを備えたミリ波レーダーについて実施の形態の例を示す平面図である。
【図５】本発明のＮＲＤガイドを備えたミリ波レーダーについて実施の形態の他の例を示す平面図である。
【図６】本発明のミリ波レーダー用の電圧制御発振部の斜視図である。
【図７】図６の電圧制御発振部に組み込まれる可変容量ダイオードを設けた配線基板の斜視図である。
【図８】本発明のＮＲＤガイドの誘電体線路部分のズレ（距離Ｌ）と高周波信号の減衰量との関係を示すグラフである。
【符号の説明】
１：下側の平行平板導体
２：誘電体線路
２ａ，２ｂ，２ｃ：誘電体線路部分
３：上側の平行平板導体[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a non-radiative dielectric line used in a high-frequency band such as a millimeter wave, which is preferably used for a millimeter wave integrated circuit or the like, and relates to a non-radiative dielectric line type millimeter wave. The present invention relates to a millimeter wave transceiver such as an integrated circuit and a millimeter wave radar module.
[0002]
[Prior art]
FIG. 2 shows the configuration of a conventional nonradiative dielectric waveguide (hereinafter referred to as an NRD guide) S1. The NRD guide S1 in FIG. 2 is a dielectric between a pair of

parallel plate conductors

11 and 13 having an interval d of λ / 2 or less with respect to a wavelength λ of an electromagnetic wave (high-frequency signal) propagating in the air at the used frequency. By interposing the line 12, the electromagnetic wave can propagate along the dielectric line 12, and the radiation wave is based on the operation principle that it is suppressed by the blocking effect of the

parallel plate conductors

11, 13.
[0003]
It is known that there are two types of electromagnetic wave propagation modes of the NRD guide S1, an LSM mode and an LSE mode, but an LSM mode with small loss is generally used. As another type of the NRD guide, there is also an NRD guide S2 provided with a curved dielectric line 14 as shown in FIG. 3, whereby an electromagnetic wave can be easily propagated in a curved manner, and a millimeter wave integrated circuit can be provided. It has the advantage that it is possible to reduce the size and design circuits with a high degree of freedom.
[0004]
2 and 3, the upper parallel plate conductor 13 is partially cut out or shown by a broken line so as to see through the inside. Reference numeral 11 denotes a lower parallel plate conductor.
[0005]
Conventionally, as a material of the

dielectric lines

12 and 14 of the NRD guides S1 and S2, Teflon (registered trademark), polystyrene or the like having a relative dielectric constant of 2 to 4 is used in view of simplicity of easy processing and low loss. Resin materials have been used.
[0006]
[Problems to be solved by the invention]
However, if the NRD guides S1 and S2 are composed of the

dielectric lines

12 and 14 made of a dielectric having a relative permittivity of 2 to 4, such as Teflon or polystyrene, which is conventionally used, bending loss at a curved portion and dielectric line There is a disadvantage that the loss at the

joints

12 and 14 is large. For this reason, a steep curved portion cannot be provided. Further, even in the case of a gentle curved portion, it is necessary to precisely determine the radius of curvature of the curved portion. Further, the usable frequency range with a small bending loss is, for example, about 1 GHz to 2 GHz near 60 GHz, which is not sufficient. This is because, when the NRD guides S1 and S2 are formed using dielectric materials having relative dielectric constants of 2 to 4, the dispersion curves of the LSM mode and the LSE mode are very close, and a part of the LSM mode electromagnetic wave This is because the mode is converted to the mode, and the loss increases.
[0007]
As a material of the

dielectric lines

12 and 14, alumina (Al ₂ O ₃ Some ceramics, such as ceramics, having a relative dielectric constant of about 10, are used. However, in order to use at a high frequency of 50 GHz or more, the widths of the

dielectric lines

12 and 14 must be extremely thin, so that processing is performed. Impractical in terms of performance and implementation.
[0008]
When a high-frequency device or a high-frequency circuit module is manufactured by an NRD guide using the

dielectric lines

12 and 14 made of an inorganic compound such as ceramics, the

dielectric lines

12 and 14 can be provided with a sharp curve. It has been difficult to produce a complicated shape composed of a plurality of straight portions and curved portions. Further, there are problems such as a difference in thermal expansion coefficient between the

parallel plate conductors

11 and 13 and the

dielectric lines

12 and 14, and furthermore, damage to the

dielectric lines

12 and 14 due to impact.
[0009]
Further, when the NRD guide is formed by a dielectric line made of a resin material such as Teflon, which has been conventionally used, it is difficult to bond the

dielectric lines

12 and 14 to the

parallel plate conductors

11 and 13, and the dielectric lines due to vibrations and thermal expansion differences. There has been a problem that the

lines

12, 14 are displaced and do not function properly.
[0010]
Accordingly, the present invention has been completed in view of the above circumstances, and an object of the present invention is to reduce the conversion of an LSM mode electromagnetic wave to an LSE mode, and to use a dielectric line with a small radius of curvature and a wide frequency range. An object of the present invention is to provide a high-performance NRD guide in which a curved portion can be manufactured, and as a result, a millimeter-wave integrated circuit or the like can be reduced in size, high in reliability, and small in loss of a high-frequency signal. Another object of the present invention is to provide a miniaturized millimeter-wave transmitter / receiver having a small transmission loss of a high-frequency signal by using such an NRD guide.
[0011]
[Means for Solving the Problems]
The non-radiative dielectric line according to the present invention comprises a dielectric line for transmitting the high-frequency signal interposed between parallel plate conductors arranged at an interval of one half or less of the wavelength λ of the high-frequency signal. In the line, the dielectric line is configured such that end faces of a plurality of dielectric line portions are opposed to each other, and the width of the dielectric line portion is smaller than the width of the dielectric line portion at a portion of the parallel plate conductor where the dielectric line portion is installed. By forming a groove that can fit the entire dielectric line portion with a wide groove, and adjusting the installation position of the dielectric line portion in the groove, the dielectric line portion is adjacent to the adjacent one. The end faces are perpendicular to the transmission direction of the high-frequency signal and are installed so as to be movable by a distance of λ / 8 or less in a direction parallel to the inner surface of the parallel plate conductor.
[0012]
The NRD guide according to the present invention can easily form a dielectric line having a complicated shape composed of a straight line portion and a curved line portion by continuously arranging a plurality of dielectric line portions so as to form a pseudo one dielectric line. Can be manufactured. In this way, a high-performance NRD guide with higher flexibility and reliability, small size, low cost, and low loss can be configured. As a result, a millimeter-wave integrated circuit or the like can be miniaturized, and a high-performance NRD guide having high reliability and small loss of high-frequency signals can be obtained.
[0013]
In addition, the means for moving the dielectric line portion as described above allows the dielectric line portion to be λ / 8 in a direction perpendicular to the transmission direction of the high-frequency signal and parallel to the inner surface of the parallel plate conductor with respect to the adjacent line. By being installed so that it can move the following distance, while maintaining the transmission characteristics of the high-frequency signal, it is electromagnetically coupled with the dielectric line portion, with other components such as high-frequency diodes and other dielectric lines. Can control the interval. As a result, the oscillation frequency of the high-frequency diode can be controlled, and the degree of coupling with other dielectric lines can be controlled.
[0014]
In the millimeter-wave transceiver according to the present invention, a high-frequency diode oscillator is provided at one end between parallel plate conductors arranged at an interval equal to or less than half the wavelength λ of the millimeter-wave signal, and the high-frequency diode oscillator is output from the high-frequency diode oscillator. A first dielectric line for transmitting a millimeter wave signal, and a bias voltage application direction arranged so as to match an electric field direction of the millimeter wave signal, and the millimeter wave signal is controlled by periodically controlling the bias voltage. A variable capacitance diode that outputs a frequency-modulated millimeter-wave signal for transmission, and one end of the variable dielectric diode that is electromagnetically coupled to the first dielectric line, or one end of which is joined to the first dielectric line, is connected to the millimeter wave signal for transmission. A second dielectric line for transmitting a part of the wave signal to the mixer side, and a ferrite plate arranged in parallel with the parallel plate conductor at a predetermined interval on a peripheral portion of the ferrite plate; A first connection portion, a second connection portion, and a third connection portion serving as input / output terminals of the millimeter wave signal, wherein the millimeter wave signal input from one connection portion is applied to a surface of the ferrite plate; A circulator for outputting the clock signal from another connecting portion adjacent thereto in a clockwise or counterclockwise direction, wherein the first connecting portion is joined to an output end of the millimeter wave signal of the first dielectric line. And a third dielectric line joined to the second connection part of the circulator for transmitting the millimeter wave signal for transmission and having a transmission / reception antenna at a tip end; and a third dielectric line received by the transmission / reception antenna. A fourth dielectric line for propagating the reception wave output from the third connection portion of the circulator to the mixer side, and a midway of the second dielectric line and the fourth dielectric line. Of dielectric line A millimeter wave provided with a mixer unit that is formed by electromagnetic coupling or bonding by bringing the intermediate waves close to each other and mixing a part of the millimeter wave signal for transmission and the reception wave to generate an intermediate frequency signal. In the transceiver, at least one of the first to fourth dielectric lines is composed of a plurality of dielectric line portions, and constitutes the non-radiative dielectric line of the present invention together with the parallel plate conductor. .
[0015]
According to the above configuration, the millimeter wave transceiver of the present invention can be a highly reliable, high performance, and small millimeter wave transceiver. In addition, it can control the oscillation frequency of the high-frequency diode, control the branch strength of the millimeter-wave signal, the degree of multiplexing, etc., adjust the transmission characteristics of the millimeter-wave transceiver to the best condition, and use different frequency bands. Can be adjusted for use.
[0016]
Further, in the millimeter-wave transceiver of the present invention, a high-frequency diode oscillator is provided at one end between parallel plate conductors arranged at an interval equal to or less than half the wavelength λ of the millimeter-wave signal, and is output from the high-frequency diode oscillator. A first dielectric line for transmitting the millimeter-wave signal, and a bias voltage application direction arranged to match an electric field direction of the millimeter-wave signal, and the millimeter-wave signal is controlled by periodically controlling the bias voltage. A variable-capacitance diode that outputs a frequency-modulated millimeter-wave signal for transmission and the first dielectric line, one end of which is disposed close to or electromagnetically coupled to one end, and one end of which is joined to the first dielectric line. A second dielectric line for transmitting a part of the millimeter wave signal to the mixer side, and a ferrite plate arranged in parallel with the parallel plate conductor at a predetermined interval on a peripheral portion of the ferrite plate; The ferrite plate has a first connection portion, a second connection portion, and a third connection portion serving as input / output terminals of the millimeter wave signal, respectively, and transmits the millimeter wave signal input from one connection portion to the ferrite plate. A circulator outputting clockwise or counterclockwise from another connecting portion adjacent in the plane of the first dielectric line, wherein the first connecting portion is connected to an output end of the millimeter wave signal of the first dielectric line. A circulator, a third dielectric line connected to the second connection part of the circulator, for transmitting the transmitting millimeter wave signal and having a transmitting antenna at a distal end, a receiving antenna at a distal end, and the like. A fourth dielectric line provided with a mixer at each end, and a third connection portion of the circulator, which is connected to the third connection portion, propagates a millimeter wave signal received and mixed by the transmission antenna, and is provided at a tip portion. Rebellion A fifth dielectric line that attenuates the received and mixed millimeter-wave signal at the radiation terminating portion, and a midway between the second dielectric line and the middle of the fourth dielectric line that are brought close to each other and electromagnetically coupled. Or a mixer unit, which is formed by bonding and mixing a part of the transmitting millimeter wave signal and the received wave to generate an intermediate frequency signal, wherein the first to fifth dielectric At least one of the body lines includes a plurality of dielectric line portions, and constitutes the nonradiative dielectric line according to claim 1 together with the parallel plate conductor.
[0017]
According to the above configuration, the millimeter wave transceiver of the present invention can be a highly reliable, high performance, and small millimeter wave transceiver. In addition, it can control the oscillation frequency of the high-frequency diode, control the branch strength of the millimeter-wave signal, the degree of multiplexing, etc., adjust the transmission characteristics of the millimeter-wave transceiver to the best condition, and use different frequency bands. Can be adjusted for use. Furthermore, the millimeter-wave signal for transmission does not enter the mixer via the circulator, and as a result, the noise of the received signal is reduced, and when applied to a millimeter-wave radar, the detection distance increases, and the millimeter-wave signal is reduced. The transmission characteristics are excellent.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
The NRD guide of the present invention will be described in detail below. FIG. 1 is a perspective view of an NRD guide of the present invention. In FIG. 1, reference numerals 1 and 3 denote lower and upper parallel plate conductors arranged at an interval of one half or less of a wavelength λ of a high-frequency signal to be propagated. This is a dielectric line, in which the end faces of the plurality of dielectric line portions 2a, 2b are opposed to each other, and the dielectric line portions 2a, 2b are high-frequency signals with respect to the adjacent dielectric line portions 2a, 2b. And is movable λ / 8 or less in a direction perpendicular to the transmission direction and parallel to the inner surfaces of the parallel plate conductors 1 and 3. When the distance L is 0, it corresponds to a state in which the center points of the facing end faces of the dielectric line portions 2a and 2b coincide with each other.
[0020]
As means for moving the dielectric line portions 2a and 2b, the portions of the parallel plate conductors 1 and 3 where the dielectric line portions 2a and 2b are installed are at most λ / 4 larger than the width of the dielectric line portions 2a and 2b. A wide groove may be formed so that the whole of the dielectric line portions 2a and 2b can be fitted therein, and the installation positions of the dielectric line portions 2a and 2b may be adjusted within the groove. In this case, the width of the groove is made to be at most λ / 4 wider than the width of the dielectric line portions 2a and 2b because the direction of transmission of the high-frequency signal of the dielectric line portions 2a and 2b is orthogonal to the direction of the parallel plate conductor. This is because the directions parallel to the inner surfaces of the surfaces 1 and 3 are two directions on the left and right sides. If one direction is set to λ / 8 and the other direction can be moved by λ / 8, the direction becomes λ / 4. Further, the minimum value may be λ / 16. In this case, one of the dielectric line portions 2a and 2b is moved by λ / 16 in one of the left and right directions, and the other dielectric line portion 2a and 2b is moved in the opposite direction. May be moved by λ / 16.
[0021]
The dielectric line portions 2a and 2b after the movement of the distance L can be fixed with an adhesive or the like. Further, the movement of the dielectric line portions 2a and 2b may be adjusted manually without using the moving mechanism as described above. In this case, a scale graduation for adjusting the position of the dielectric line portions 2a and 2b may be formed on the inner surfaces of the parallel plate conductors 1 and 3 by a groove having a minute depth or formed by a printing method or the like.
[0022]
The end faces of these dielectric line portions 2a and 2b need only be substantially perpendicular to the transmission direction of the high-frequency signal, and need not be completely perpendicular. Further, the end face does not have to be flat and may have a curved surface to some extent. Further, if the distance between the end faces is not more than 1/8 of the wavelength λ, the end faces need not be in direct contact.
[0023]
Note that the wavelength λ of the high-frequency signal corresponds to the wavelength of the high-frequency signal at the operating frequency in the air.
[0024]
The parallel plate conductors 1 and 3 for the NRD guide S of the present invention are made of Cu, Al, Fe, SUS (stainless steel), Ag, Au, Pt, etc. in terms of high electric conductivity and workability, and are forged. These conductor layers may be formed on the surface of a metal plate processed by casting, die casting, grinding, or the like, or an insulating plate made of ceramics, resin, or the like.
[0025]
The dielectric line 2 of the NRD guide S of the present invention is preferably made of a ceramic having a Q value of 1000 or more at a working frequency of 60 GHz and containing a composite oxide of Mg, Al, and Si as a main component. This ceramic has a relative dielectric constant of about 4.5 to 8. The relative permittivity is limited to this range because when the relative permittivity is less than 4.5, the conversion of the LSM mode electromagnetic wave to the LSE mode increases as described above. On the other hand, if the relative dielectric constant exceeds 8, the width of the dielectric line 2 must be extremely thin when used at a frequency of 50 GHz or more, which makes processing difficult, deteriorates the shape accuracy, and reduces the strength. Problems also arise in terms of points.
[0026]
Further, in the present invention, the distance L of deviation between the dielectric line portions 2a and 2b constituting the series of dielectric lines 2 is set to λ / 8 or less. This is because if it is larger than λ / 8, the transmission loss of the high-frequency signal increases. When the number of the dielectric line portions 2a and 2b increases or when a further low transmission loss is required, it is preferable to set the distance L to a smaller value of λ / 8 or less. If the distance L is set to almost 0, the transmission loss of the high-frequency signal is minimized.
[0027]
In the case of ceramics having a Q value of 1000 or more at a working frequency of 60 GHz and containing a composite oxide of Mg, Al, and Si as a main component, the ceramics have a frequency of 60 GHz included in a microwave band and a millimeter wave band in recent years. This is to realize a sufficiently low loss property as a dielectric line used.
[0028]
The composition and composition ratio of the dielectric line 2 are represented by a molar ratio composition formula of xMgO.yAl. ₂ O ₃ ・ ZSiO ₂ When expressed as follows, a composite oxide of Mg, Al, and Si satisfying x = 10 to 40 mol%, y = 10 to 40 mol%, z = 20 to 80 mol%, and x + y + z = 100 mol% is mainly used. What is used as a component is good.
[0029]
The reason for limiting the composition ratio of the main component of the ceramic (dielectric ceramic composition) as the material of the dielectric line 2 of the NRD guide S of the present invention to the above range is as follows. That is, the reason why x is set to 10 to 40 mol% is that if it is less than 10 mol%, a good sintered body cannot be obtained, and if it exceeds 40 mol%, the relative dielectric constant becomes large. In particular, x is preferably 15 to 35 mol% from the viewpoint that the Q value at 60 GHz is 2000 or more.
[0030]
Also, the reason why y is set to 10 to 40 mol% is that if y is less than 10 mol%, a good sintered body cannot be obtained, and if y exceeds 40 mol%, the relative dielectric constant increases. . y is preferably 17 to 35 mol% from the viewpoint that the Q value at 60 GHz is 2000 or more.
[0031]
The reason why z is set to 20 to 80 mol% is that when z is smaller than 20 mol%, the relative permittivity increases, and when z exceeds 80 mol%, a good sintered body cannot be obtained and the Q value decreases. Because. z is preferably 30 to 65 mol% from the viewpoint that the Q value at 60 GHz is 2000 or more.
[0032]
These MgO, Al ₂ O ₃ , SiO ₂ X, y, and z, which indicate mol%, can be specified by an analytical method such as an EPMA (Electron Probe Micro Analysis) method, an XRD (X-ray Diffraction: X-ray diffraction) method, or the like.
[0033]
The ceramic (dielectric ceramic composition) for the dielectric line 2 of the NRD guide S of the present invention has a main crystal phase of cordierite (2MgO.2Al). ₂ O ₃ ・ 5SiO ₂ ) And mullite (3Al ₂ O ₃ ・ 2SiO ₂ ), Spinel (MgO.Al ₂ O ₃ ), Protoenstatite ｛magnesium metasilicate (MgO.SiO) ₂ ), A kind of steatite, and clinoenstatite, magnesium metasilicate (MgO.SiO) ₂ ) As a main type of steatite, forsterite (2MgO.SiO) ₂ ), Cristobalite @ silicic acid (SiO _Two ), Tridymite silicic acid (SiO ₂ ), Safarin (a kind of silicate of Mg and Al) and the like may be precipitated, but the precipitated phase differs depending on the composition. In the dielectric porcelain composition of the present invention, a crystalline phase composed of cordierite alone may be used.
[0034]
The dielectric ceramic composition for the dielectric line 2 of the NRD guide S of the present invention is manufactured as follows. As raw material powder, for example, MgCO ₃ Powder, Al ₂ O ₃ Powder, SiO ₂ Using powders, these are weighed at a predetermined ratio, wet-mixed, dried, and the mixture is calcined at 1100 to 1300 ° C in the air, and then pulverized to powder. An appropriate amount of a resin binder is added to the obtained powder, molded, and the molded body is fired at 1300 to 1450 ° C. in the atmosphere to obtain a powder.
[0035]
The raw material powder composed of the elements Mg, Al, and Si contained in the raw material powder may be any of inorganic compounds such as oxides, carbonates, and acetates, or organic compounds such as organic metals. What is necessary is just what becomes an oxide.
[0036]
Note that the main component of the dielectric ceramic composition of the dielectric line 2 of the NRD guide S of the present invention is mainly composed of a composite oxide of Mg, Al, and Si, and has a Q value of 1000 or more at 60 GHz. In addition to the above-mentioned elements, impurities of the pulverized ball and the raw material powder may be mixed, and other components may be contained for the purpose of controlling the sintering temperature range and improving mechanical properties. . For example, rare earth element compounds, oxides such as Ba, Sr, Ca, Ni, Co, In, Ga, and Ti, and non-oxides such as nitrides such as silicon nitride. These may include one kind or plural kinds.
[0037]
The high frequency band referred to in the present invention corresponds to a microwave band and a millimeter wave band of several tens to several hundreds of GHz, and for example, a high frequency band of 30 GHz or more, particularly 50 GHz or more, and more preferably 70 GHz or more is suitable.
[0038]
Further, other materials for the dielectric line 2 may be resin-based materials such as Teflon, polystyrene, and glass epoxy resin, and may be alumina ceramics, glass ceramics, forsterite ceramics, and the like. Cordierite ceramics are preferred in terms of miniaturization and reliability.
[0039]
The NRD guide S of the present invention is used for a wireless LAN, a millimeter wave radar of an automobile, etc., for example, irradiates an obstacle around the automobile and another automobile with a millimeter wave, and reflects a reflected wave to the original millimeter. An intermediate frequency signal is obtained by synthesizing with the wave, and by analyzing the intermediate frequency signal, a distance to an obstacle and another vehicle, a moving speed thereof, and the like can be measured.
[0040]
Thus, according to the present invention, a highly reliable, high-performance, and compact NRD guide can be configured. In addition, while maintaining the transmission characteristics of the high-frequency signal, it is possible to control the distance between another dielectric line and another component such as a high-frequency diode, which is electromagnetically coupled to the dielectric line portion. As a result, the oscillation frequency of the high-frequency diode can be controlled, and the degree of coupling with other dielectric lines can be controlled. Also, preferably, since a dielectric line made of ceramics having a lower dielectric constant than conventional alumina ceramics or the like is used, conversion of LSM mode electromagnetic waves to LSE mode can be reduced, and loss of high frequency signals can be suppressed. .
[0041]
A millimeter wave transceiver using the NRD guide of the present invention will be described below. 4 and 5 show a millimeter-wave radar as a millimeter-wave transceiver of the present invention. FIG. 4 is a plan view of an integrated transmission antenna and reception antenna, and FIG. It is a top view of an independent thing.
[0042]
In FIG. 4, reference numeral 51 denotes one parallel plate conductor (the other is omitted), and 52 denotes a voltage-controlled millimeter-wave signal oscillating unit (voltage) provided at one end of a first dielectric line 53 and having a high-frequency diode oscillator. Control oscillator), and periodically controls the bias voltage of the variable capacitance diode disposed near the high-frequency diode of the first dielectric line 53 so that the bias voltage application direction matches the electric field direction of the high-frequency signal. Then, by forming a triangular wave, a sine wave or the like, the signal is output as a frequency-modulated millimeter wave signal for transmission.
[0043]
53 is a first dielectric line on which a high-frequency diode oscillator is provided at one end to propagate a transmission millimeter-wave signal obtained by modulating a millimeter-wave signal output from the high-frequency diode oscillator, and 54 is a first dielectric line. 3, a circulator 55 made of a ferrite disk or the like having first, second, and

third connection portions

54a, 54b, 54c respectively coupled to the fourth

dielectric lines

53, 55, 57; The third dielectric line 56 is connected to the second connecting portion 54b, propagates the millimeter wave signal, and has a transmitting / receiving antenna 56 at the distal end. The third dielectric line 56 has a distal end of the third dielectric line 55 having a tapered shape or the like. This is a transmission / reception antenna configured.
[0044]
The transmitting / receiving antenna 56 inputs and outputs a high-frequency signal through a through hole formed in the parallel plate conductor 51, and a horn antenna installed on the outer surface of the parallel plate conductor 51 via a metal waveguide connected to the through hole. And so on.
[0045]
Reference numeral 57 denotes a fourth dielectric line which receives the transmission / reception antenna 56, propagates through the third dielectric line 55, and outputs a reception wave output from the third connection portion 54 c of the circulator 54 to the mixer 59 side; Is a second dielectric line that is disposed close to the first dielectric line 53 so that one end side is electromagnetically coupled, and transmits a part of the millimeter wave signal for transmission to the mixer 59 side, and 58a is a second dielectric line. Is a non-reflection terminal (terminator) provided at one end of the dielectric line 58 on the side opposite to the mixer 59. In the figure, M1 designates a part of the millimeter wave signal for transmission and a reception wave by making the middle part of the second dielectric line 58 and the middle part of the fourth dielectric line 57 close and electromagnetically coupled. This is a mixer unit that generates an intermediate frequency signal by mixing.
[0046]
The circulator 54 of the millimeter wave transmitter / receiver of the present invention is provided at a predetermined interval, for example, at an angle of 120 ° with respect to the center point of the ferrite disk, at the periphery of a pair of ferrite disks disposed in parallel between the

parallel plate conductors

51, 51. It has a first connection portion 54a, a second connection portion 54b, and a third connection portion 54c which are arranged at intervals and are respectively input / output terminals of a millimeter wave signal, and the millimeters input from one connection portion. The wave signal is output from another connecting portion adjacent in the clockwise or counterclockwise direction in the plane of the ferrite disk. Further, a magnet for rotating the wavefront of the electromagnetic wave propagating through the ferrite disk is provided in a portion of the outer main surface of the parallel plate conductor 51 facing the ferrite disk, and a magnetic field line is applied in a direction substantially perpendicular to the ferrite disk. (Up-down direction). The ferrite plate is not limited to a disk-shaped one, but may be a polygonal one or the like.
[0047]
Further, as another embodiment of the millimeter wave transceiver of the present invention, there is a type shown in FIG. 5 in which a transmitting antenna and a receiving antenna are independent. In the figure, reference numeral 61 denotes one parallel plate conductor (the other is omitted), and 62 denotes a voltage-controlled millimeter-wave signal oscillating unit provided at one end of the first dielectric line 63 and having a high-frequency diode oscillator. The bias voltage of the variable capacitance diode arranged near the high-frequency diode of the first dielectric line 63 is periodically controlled so that the bias voltage application direction matches the electric field direction of the high-frequency signal, so that a triangular wave, a sine wave, etc. As a result, a frequency-modulated transmission millimeter wave signal is output.
[0048]
63 is a first dielectric line having a high-frequency diode oscillator attached to one end thereof for transmitting a millimeter-wave signal for transmission in which a millimeter-wave signal output from the high-frequency diode oscillator is modulated, and 64 is a first dielectric line. 3. A circulator made of a ferrite disk or the like having first, second, and third connection portions (similar to FIG. 3 and not shown) connected to the fifth

dielectric lines

63, 65, 67, respectively. , 65 are third dielectric lines connected to the second connection of the circulator 64 for transmitting the millimeter wave signal and having a transmitting antenna 66 at the distal end. 66 is a distal end of the third dielectric line 65. Is formed in a tapered shape or the like, is connected to a third connection portion of the circulator 64, and a non-reflection terminal portion 67a for attenuating a millimeter wave signal for transmission is provided at the tip. A fifth dielectric waveguide.
[0049]
Reference numeral 68 denotes a second dielectric line which is disposed close to the first dielectric line 63 such that one end is electromagnetically coupled, and transmits a part of a millimeter wave signal for transmission to the mixer 71 side. A non-reflection terminal 69 provided at one end of the second dielectric line 68 opposite to the mixer 71 is a fourth dielectric line for propagating a reception wave received by the reception antenna 70 to the mixer 71 side. It is. In the figure, M2 indicates a part of the millimeter wave signal for transmission and the reception wave by making the middle of the second dielectric line 68 and the middle of the fourth dielectric line 69 close to each other and electromagnetically coupled. Are mixed to generate an intermediate frequency signal.
[0050]
The transmitting antenna 66 and the receiving antenna 70 input or output a high-frequency signal through a through hole formed in the parallel plate conductor 61, and a metal waveguide connected to the through hole on the outer surface of the parallel plate conductor 61. An installed horn antenna or the like may be used.
[0051]
In the millimeter wave transmitter / receiver of the present invention, in FIG. 4, one end of the second dielectric line 58 is arranged close to or joined to the first dielectric line 53. At the joint, the first dielectric line 53 is formed in a linear shape, the second dielectric line 58 is formed in an arc shape, and the radius of curvature r of the arc portion is set to be equal to or longer than the wavelength λ of the high-frequency signal. As a result, a high-frequency signal can be branched with equal output while reducing loss. Further, at the joint, the second dielectric line 58 may be formed in a linear shape, the first dielectric line 53 may be formed in an arc shape, and the radius of curvature r of the arc portion may be equal to or longer than the wavelength λ of the high-frequency signal. In this case, the same effect as above can be obtained.
[0052]
In the mixer 59, the second dielectric line 58 and the fourth dielectric line 57 can be joined. In this case, as in the above case, it is preferable that one of the joints of the

dielectric lines

58 and 57 is formed in an arc shape and the radius of curvature r of the arc portion is equal to or longer than the wavelength λ of the high-frequency signal. . In the case where the second dielectric line 58 and the fourth dielectric line 57 are arranged close to each other so as to be electromagnetically coupled, the second dielectric line 58 and the fourth dielectric line 57 are arranged in the vicinity of the second dielectric line 58 and the fourth dielectric line 57. By forming at least one of the adjacent portions with an arc shape, it is possible to obtain a configuration of the adjacent arrangement.
[0053]
Preferably, the radius of curvature r of the above-mentioned joint is 3λ or less, and if it exceeds 3λ, the joining structure becomes large and the advantage of miniaturization cannot be obtained. When the radius of curvature r of the joint is set smaller than the wavelength λ, the branching strength to the dielectric line having the arc-shaped joint is reduced.
[0054]
Such a joint structure between the first dielectric line 53 and the second dielectric line 58, a joint structure between the second dielectric line 58 and the fourth dielectric line 57, and the second dielectric line The configuration of the proximity arrangement between the line 58 and the fourth dielectric line 57 is the same as above in the case of FIG.
[0055]
These various components are provided between parallel plate conductors arranged at an interval of one half or less of the wavelength λ of the millimeter wave signal.
[0056]
4, a pulse modulation control can be performed by providing a switch in the middle of the first dielectric line 53 and turning it on and off (ON-OFF). For example, as shown in FIG. 7, a second choke type bias supply line 112 is formed on one main surface of a wiring board 88, and a beam lead type PIN diode or a Schottky barrier diode solder-mounted is provided in the middle thereof. Switch. In FIG. 7, E indicates the direction of the electric field of the high-frequency signal propagating in the dielectric line 77, and 111 indicates a connection pad for connecting a pulse modulation diode such as a PIN diode or a Schottky barrier diode.
[0057]
By applying the wiring substrate 88 to the circulator 54 between the signal branch portion of the first dielectric line 53 and the second dielectric line 58 and applying a bias voltage of a pulse modulation diode such as a PIN diode or a Schottky barrier diode. The direction is arranged so as to match the direction of the electric field of the high frequency signal of the LSM mode, and is interposed in the first dielectric line 53. Further, another circulator is interposed in the first dielectric line 53, the first dielectric line 53 is connected to the first and third connection portions, and another dielectric line is connected to the second connection portion. May be connected, and a switch provided with a Schottky barrier diode in a configuration as shown in FIG. 7 may be provided on the end face of the tip of the dielectric line.
[0058]
In the configuration shown in FIG. 5, the circulator 64 may be omitted, and the transmission antenna 66 may be connected to the end of the first dielectric line 63. In this case, the size is reduced, but a part of the received wave is easily mixed into the voltage controlled oscillator (millimeter wave signal oscillator) 62 and causes noise or the like.
[0059]
In the type of FIG. 5, the second dielectric line 68 is disposed close to the third dielectric line 65 so that one end side is electromagnetically coupled to the third dielectric line 65 or one end is joined to the third dielectric line 65. , A part of the millimeter wave signal for transmission may be arranged to propagate to the mixer 71 side. This configuration also has the same functions and effects as those of FIG.
[0060]
In FIG. 5, a switch having the same configuration as that of FIG. 7 is provided in the middle of the first dielectric line 63, and pulse modulation control can be performed by turning it on and off. For example, as shown in FIG. 7, a second choke type bias supply line 112 is formed on one main surface of a wiring board 88, and a beam lead type PIN diode or a Schottky barrier diode mounted by soldering is provided in the middle thereof. Switch. This wiring board 88 is connected between the signal branching portion of the first dielectric line 63 and the second dielectric line 68 and the circulator 64 and the bias voltage application direction of the PIN diode or the Schottky barrier diode is set in the LSM mode. Are arranged so as to match the direction of the electric field of the high-frequency signal, and are interposed in the first dielectric line 63.
[0061]
In addition, another circulator is interposed in the first dielectric line 63, the first dielectric line 63 is connected to the first and third connection portions, and another dielectric line is connected to the second connection portion. And a switch provided with a Schottky barrier diode having a configuration as shown in FIG. 7 may be provided on the end face of the distal end of the dielectric line.
[0062]
In these millimeter wave transceivers, the distance between the parallel plate conductors is the wavelength of the millimeter wave signal in the air, and is not more than half the wavelength λ at the operating frequency.
[0063]
The millimeter wave transceiver shown in FIGS. 4 and 5 employs an FMCW (Frequency Modulation Continuous Waves) system, and the operation principle of the FMCW system is as follows. An input signal whose voltage amplitude changes with time in the form of a triangular wave is input to the modulation signal input MODIN terminal of the voltage controlled oscillator, the output signal is frequency-modulated, and the output frequency shift of the voltage controlled oscillator is converted into a triangle wave or the like. Shift so that When an output signal (transmission wave) is radiated from the transmission / reception antenna 56 and the transmission antenna 66 and a target is present in front of the transmission / reception antenna 56 and the transmission antenna 66, a time difference corresponding to a reciprocation of the propagation speed of the radio wave is obtained. The reflected wave (received wave) returns. At this time, the frequency difference between the transmission wave and the reception wave is output to the IFOUT terminal on the output side of the

mixers

59 and 71.
[0064]
By analyzing the frequency components such as the output frequency of the IFOUT terminal, Fif = 4R · fm · Δf / c ｛Fif: IF (Intermediate Frequency) output frequency, R: distance, fm: modulation frequency, Δf: frequency deviation The distance can be obtained from the relational expression of width, c: speed of light｝.
[0065]
As described above, when the present invention is applied to a millimeter-wave radar of an automobile, an obstacle around the automobile and other automobiles are irradiated with the millimeter wave, and the reflected wave is synthesized with the original millimeter wave to obtain an intermediate frequency signal. By analyzing this intermediate frequency signal, it is possible to measure the distance to obstacles and other vehicles, their moving speed, and the like.
[0066]
The voltage controlled oscillators 52 and 62 using the high-frequency diode oscillator in the millimeter wave transceiver according to the present invention will be described below. 6 and 7 show an NRD guide type high-frequency diode oscillator in the millimeter wave transceiver according to the present invention. In these figures, 71 is a pair of parallel plate conductors, and 72 is for mounting (mounting) a Gunn diode 73. A metal member such as a substantially rectangular parallelepiped metal block, 73 is a gun diode which is one kind of a high-frequency diode that oscillates microwaves and millimeter waves, and 74 is provided on one side of the metal member 72 and applies a bias voltage to the gun diode 73. A wiring board formed with a choke-type bias supply line 74a which functions as a low-pass filter for supplying and preventing high-frequency signal leakage, and a metal foil ribbon 75 for connecting the choke-type bias supply line 74a to the upper conductor of the Gunn diode 73. The strip-shaped conductor 77 is disposed near the Gunn diode 73 to receive a high-frequency signal and transmit it to the outside. Is the cause dielectric line (corresponding to the first dielectric line 53 and 63).
[0067]
In FIG. 6, the choke-type bias supply line 74a has a wide line and a narrow line each having a length of approximately λ / 4, and the band-shaped conductor 75 has a length of approximately ｛(3/4) + m. ｝ Λ (m is an integer of 0 or more). The length of the strip conductor 75 is preferably about 3λ / 4 to about ｛(3/4) +3｝ λ, and when it exceeds about ｛(3/4) +3｝ λ, the length of the strip conductor 75 becomes longer, and the strip conductor 75 is bent, twisted, or the like. Is likely to occur, the characteristics such as the oscillation frequency among individual high-frequency diode oscillators vary greatly, and various resonance modes are generated to generate a signal having a frequency different from the desired oscillation frequency. More preferably, approximately 3λ / 4, approximately {(3/4) +1} λ.
[0068]
Further, the reason why it is set to approximately ｛(3/4) + m｝ λ is that resonance is possible even if it is slightly deviated from ｛(3/4) + m｝ λ. For example, the band-shaped conductor 75 may be formed to be about 10% to 20% longer than {(3/4) + m} λ. In this case, the length of the first pattern of the choke-type bias supply line 74a in contact with the band-shaped conductor 75 This is because part of λ / 4 is considered to contribute to resonance. Therefore, the length of the strip-shaped conductor 75 can be changed within a range of about (3/4) + m｝ λ ± 20%.
[0069]
The material of the choke-type bias supply line 74a and the strip-shaped conductor 75 is made of Cu, Al, Au, Ag, W, Ti, Ni, Cr, Pd, Pt, and the like. In particular, Cu and Ag have good electrical conductivity. This is preferable in that the loss is small and the oscillation output is large.
[0070]
The band-shaped conductor 75 is electromagnetically coupled to the metal member 72 at a predetermined distance from the surface of the metal member 72, and is bridged between the choke-type bias supply line 74 a and the Gunn diode 73. That is, one end of the strip-shaped conductor 75 is connected to one end of the choke-type bias supply line 74a by soldering or the like, and the other end of the strip-shaped conductor 75 is connected to the upper conductor of the gun diode 73 by soldering or the like. The middle part except for the connection part is floating in the air.
[0071]
The metal member 72 is not particularly limited as long as it is a metal conductor because the metal member 72 also serves as an electrical ground (earth) for the Gunn diode 73, as long as the material is a metal (including alloy) conductor. It is made of brass (brass: Cu-Zn alloy), Al, Cu, SUS (stainless steel), Ag, Au, Pt, or the like. The metal member 72 is made of a metal block made entirely of metal, an insulated substrate made of ceramics, plastic, or the like, which is entirely or partially metal-plated, or an insulated substrate entirely or partially coated with a conductive resin material or the like. It may be something.
[0072]
The dielectric line 77 is equivalent to the first

dielectric lines

53 and 63 in FIGS. 4 and 5, and is made of cordierite (2MgO.2Al) as described above. ₂ O ₃ ・ 5SiO ₂ ) Ceramics (dielectric constant 4 to 5) are preferable, and these have low loss in a high frequency band. The distance between the Gunn diode 73 and the dielectric line 77 is preferably about 1.0 mm or less, and if it exceeds 1.0 mm, the loss is reduced to exceed the maximum separation width at which electromagnetic coupling is possible.
[0073]
As the high-frequency diode of the present invention, a microwave diode such as an impatt (impact ionisation avalanche transit time) / diode, a trappat (trapped plasma avalanche triggered transit) / diode, a gun diode, or a microwave diode or a millimeter-wave diode is preferably used. used.
[0074]
The switch shown in FIG. 7 is provided with a frequency modulation diode 110 composed of a variable capacitance diode such as a varactor diode. A second choke type bias supply line 112 is formed on one main surface of a wiring board 88, and the switch is provided in the middle. This is a switch provided with a frequency modulation diode 110 which is solder-mounted. By controlling the bias voltage applied to the frequency modulation diode 110, the oscillation frequency of the Gunn diode 73 can be controlled. In FIG. 7, E indicates the direction of the electric field of the high-frequency signal propagating in the dielectric line 77, and 111 indicates a connection pad for connecting the frequency modulation diode 110.
[0075]
【Example】
Examples of the present invention will be described below.
[0076]
(Example)
The NRD guide S of FIG. 1 was configured as follows. As the material of the dielectric line 2, ceramics containing a composite oxide of Mg, Al, and Si as main components and having various composition ratios were manufactured. Table 1 shows their relative dielectric constants and Q values at a frequency of 60 GHz.
[0077]
[Table 1]

[0078]
As a pair of parallel flat conductors 1 and 3, metal plates made of aluminum and having a length of 80 mm × a width of 80 mm × a thickness of 2 mm were arranged at an interval d of 1.8 mm. 24 dielectric lines 2 made of cordierite ceramics were interposed. The cross-sectional shape of the dielectric line 2 is a rectangle having a height of about 1.8 mm and a width of 0.8 mm, and the two dielectric line portions 2a and 2b are arranged at a distance L. FIG. 8 shows the result of measuring the frequency characteristics of the NRD guide S. This figure shows the relationship between the deviation (distance L) and the transmission loss (| S21 |) at a frequency of 77 GHz. When the distance L between the dielectric line portions 2a and 2b is λ / 8 or less, the dielectric line 2 resulted in an insertion loss of 1 dB or less.
[0079]
It should be noted that the present invention is not limited to the above embodiment, and various changes may be made without departing from the spirit of the present invention.
[0080]
【The invention's effect】
According to the NRD guide of the present invention, the dielectric line is configured such that the end faces of the plurality of dielectric line portions face each other, and the dielectric line portion is provided at the portion of the parallel plate conductor where the dielectric line portion is installed. By forming a groove that can fit the entire dielectric line portion with a groove wider than the width of the dielectric line portion and adjusting the installation position of the dielectric line portion within the groove, the dielectric line portion is adjacent to the groove. The LSM mode electromagnetic wave is generated by the end faces of the electromagnetic wave of the LSM mode being installed so that the end faces thereof are orthogonal to the transmission direction of the high-frequency signal and can move a distance of λ / 8 or less in a direction parallel to the inner surface of the parallel plate conductor. Conversion to the LSE mode can be reduced, and a dielectric line having a complicated shape including a straight portion and a curved portion can be easily manufactured. Further, since the dielectric line can be downsized by providing a steep curved portion, the whole can be downsized. Even if a jig for supporting the dielectric line, a circuit board, and the like are made of a resin material and arranged near the dielectric line, the influence of the influence is reduced.
[0081]
In addition, even with the combination of the dielectric lines including the linear portions, a line that cannot be drawn unless it is a curve can be manufactured by the combination of the intermittent linear portions without changing the shape of the joint end face.
[0082]
Further, while maintaining the transmission characteristics of the high-frequency signal, it is possible to control the distance between another dielectric line and another component such as a high-frequency diode, which is electromagnetically coupled to the dielectric line portion. As a result, the oscillation frequency of the high-frequency diode can be controlled, and the degree of coupling with other dielectric lines can be controlled.
[0083]
Preferably, the dielectric line is made of a ceramic mainly composed of a composite oxide of Mg, Al, and Si and has a Q value of 1000 or more at a measurement frequency of 60 GHz, so that the dielectric line is lower than a conventional alumina ceramic or the like. By using a dielectric line made of a ceramic having a relative dielectric constant, conversion of an LSM mode electromagnetic wave into an LSE mode can be reduced, and loss of a high-frequency signal can be suppressed.
[0084]
Also preferably, the molar ratio composition formula of the composite oxide is xMgO.yAl ₂ O ₃ ・ ZSiO ₂ (Where x = 10 to 40 mol%, y = 10 to 40 mol%, z = 20 to 80 mol%, x + y + z = 100 mol%), the transmission loss is further reduced, and An NRD guide using an inexpensive and high-precision dielectric line can be manufactured.
[0085]
The millimeter wave transceiver according to the present invention includes a type including a transmitting / receiving antenna and a type including a transmitting antenna and a receiving antenna that are independent of each other. By constituting the non-radiative dielectric line of the present invention together with the conductor, the conversion of the LSM mode electromagnetic wave propagating through the dielectric line to the LSE mode is small, and therefore the dielectric line has a small radius of curvature and a wide frequency range of use. A steep curved portion can be manufactured, and as a result, the millimeter wave transceiver can be used in a wide frequency range, can be reduced in size, can be easily processed, and can be manufactured with a high degree of freedom.
[0086]
In addition, it can control the oscillation frequency of the high-frequency diode, control the branch strength of the millimeter-wave signal, the degree of multiplexing, etc., adjust the transmission characteristics of the millimeter-wave transceiver to the best condition, and use different frequency bands. Can be adjusted for use.
[0087]
Further, in the type in which the transmitting antenna and the receiving antenna are independent, the millimeter wave signal for transmission does not enter the mixer via the circulator, and as a result, the noise of the received signal is reduced and the detection distance is increased, and furthermore, The transmission characteristics of the millimeter wave signal are excellent.
[Brief description of the drawings]
FIG. 1 is a perspective view of the inside of an NRD guide of the present invention as seen through.
FIG. 2 is a perspective view of the inside of a conventional NRD guide seen through.
FIG. 3 is a perspective view showing the inside of another conventional NRD guide.
FIG. 4 is a plan view showing an example of an embodiment of a millimeter-wave radar including an NRD guide according to the present invention.
FIG. 5 is a plan view showing another example of the embodiment of the millimeter wave radar provided with the NRD guide of the present invention.
FIG. 6 is a perspective view of a voltage controlled oscillator for a millimeter wave radar according to the present invention.
FIG. 7 is a perspective view of a wiring board provided with a variable capacitance diode incorporated in the voltage controlled oscillator of FIG. 6;
FIG. 8 is a graph showing the relationship between the deviation (distance L) of the dielectric line portion of the NRD guide of the present invention and the amount of attenuation of a high-frequency signal.
[Explanation of symbols]
1: Lower parallel plate conductor
2: Dielectric line
2a, 2b, 2c: dielectric line portion
3: Upper parallel plate conductor

Claims

In a non-radiative dielectric line in which a dielectric line for transmitting the high-frequency signal is interposed between parallel plate conductors arranged at an interval equal to or less than half the wavelength λ of the high-frequency signal, the dielectric line includes a plurality of dielectric lines. of the end faces together are configured to face the dielectric line portion, the entire dielectric line portion in the wide groove than the width of the site in a dielectric line portion of the parallel flat conductors installing a pre Symbol dielectric guide portion Is formed, and the installation position of the dielectric line portion is adjusted in the groove, so that the dielectric line portion is orthogonal to the transmission direction of the high-frequency signal with respect to the adjacent one. A non-radiative dielectric line, wherein the non-radiative dielectric line is provided so as to be movable by a distance of λ / 8 or less in a direction parallel to the inner surface of the parallel plate conductor.

Between parallel plate conductors arranged at an interval of one half or less of the wavelength λ of the millimeter wave signal,
A first dielectric line that is provided at one end with a high-frequency diode oscillator and propagates a millimeter-wave signal output from the high-frequency diode oscillator;
A variable capacitor that is arranged so that a bias voltage application direction coincides with an electric field direction of the millimeter wave signal, and outputs the millimeter wave signal as a frequency-modulated transmission millimeter wave signal by periodically controlling the bias voltage. A diode,
A second dielectric line that is disposed close to or connected to the first dielectric line so that one end side is electromagnetically coupled to the mixer and transmits a part of the transmission millimeter wave signal to the mixer side; When,
A first connection portion, a second connection portion, and a third connection portion which are arranged at predetermined intervals on a peripheral portion of a ferrite plate provided in parallel with the parallel plate conductor and serve as input / output terminals of the millimeter wave signal, respectively. A circulator that outputs the millimeter-wave signal input from one connection part from another connection part adjacent thereto clockwise or counterclockwise in the plane of the ferrite plate. A circulator to which the first connection part is joined to an output end of the millimeter wave signal of one of the dielectric lines;
A third dielectric line joined to the second connection portion of the circulator, for transmitting the transmission millimeter wave signal, and having a transmission / reception antenna at a tip end;
A fourth dielectric line that is received by the transmission / reception antenna, propagates through the third dielectric line, and propagates a reception wave output from the third connection portion of the circulator to a mixer side;
The middle of the second dielectric line and the middle of the fourth dielectric line are brought close to each other and electromagnetically coupled or joined, and a part of the millimeter wave signal for transmission and the reception wave are formed. And a mixer unit that mixes and generates an intermediate frequency signal.
2. A non-radiative dielectric line according to claim 1, wherein at least one of said first to fourth dielectric lines comprises a plurality of dielectric line portions, and forms said non-radiative dielectric line together with said parallel plate conductor. Transceiver.

Between parallel plate conductors arranged at an interval of one half or less of the wavelength λ of the millimeter wave signal,
A first dielectric line that is provided at one end with a high-frequency diode oscillator and propagates a millimeter-wave signal output from the high-frequency diode oscillator;
A variable capacitor that is arranged so that a bias voltage application direction coincides with an electric field direction of the millimeter wave signal, and outputs the millimeter wave signal as a frequency-modulated transmission millimeter wave signal by periodically controlling the bias voltage. A diode,
A second dielectric line that is disposed close to or connected to the first dielectric line so that one end side is electromagnetically coupled to the mixer and transmits a part of the transmission millimeter wave signal to the mixer side; When,
A first connection portion, a second connection portion, and a third connection portion which are arranged at predetermined intervals on a peripheral portion of a ferrite plate provided in parallel with the parallel plate conductor and serve as input / output terminals of the millimeter wave signal, respectively. A circulator that outputs the millimeter-wave signal input from one connection part from another connection part adjacent thereto clockwise or counterclockwise in the plane of the ferrite plate. A circulator having the first connection unit connected to an output end of the millimeter wave signal of one of the dielectric lines;
A third dielectric line that is connected to the second connection part of the circulator, propagates the millimeter wave signal for transmission, and has a transmission antenna at a tip end;
A fourth dielectric line having a receiving antenna at the tip and a mixer at the other end,
Fifth, which is connected to the third connection part of the circulator and propagates the received and mixed millimeter-wave signal at the transmitting antenna and attenuates the received and mixed millimeter-wave signal at a non-reflection terminal provided at the tip end. And a dielectric line of
Made by the second or bonding dielectric waveguide was midway between close the middle of the fourth dielectric waveguide of be electromagnetically coupled, and a portion received waves of the millimeter-wave signal for the transmission And a mixer unit that mixes and generates an intermediate frequency signal.
2. A millimeter wave transmission / reception system according to claim 1, wherein at least one of said first to fifth dielectric lines comprises a plurality of dielectric line portions, and forms said non-radiative dielectric line together with said parallel plate conductor. vessel.