【０００１】
【発明の属する技術分野】
本発明は、ミリ波集積回路等の高周波回路に組み込まれるガンダイオード発振器等の高周波ダイオード発振器であって、発振周波数の調整機能を有する非放射性誘電体線路型の高周波ダイオード発振器に関するものである。
【０００２】
【従来の技術】
従来のガンダイオード発振器を図５に示す。同図において、１は一対の平行平板導体であり、それらの間隔ｚをｚ≦λ／２とすることにより外部から誘電体線路７へのノイズの侵入をなくしかつ外部への高周波信号の放射をなくして信号を伝送させる、所謂非放射性誘電体線路（nonradiative dielectric waveguide で、以下、ＮＲＤガイドという）を構成する。なお、λ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）の波長である。
【０００３】
また、２はガンダイオードを設置（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、３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、４は金属部材２の一側面に設置され、ガンダイオード３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４ａを形成した配線基板、５はチョーク型バイアス供給線路４ａとガンダイオード３の上部導体とを接続する金属箔リボン等の帯状導体、７はガンダイオード３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である。なお、図５では、内部を透視するために平行平板導体１の上側を一部切り欠いている。また、帯状導体５は金属部材２の表面から所定間隔をあけてチョーク型バイアス供給線路４ａとガンダイオード３との間に架け渡されている。
【０００４】
そして、帯状導体５の主面に平行な主面を有する略四角柱状の誘電体チップ８を帯状導体５に近接配置して電磁結合させ、高周波信号の発振周波数を制御可能とすることを本出願人は先に提案した（特願平１１−２３７３１８号）。また、この場合、チョーク型バイアス供給線路４ａは、幅の広い線路の空間的周期と幅の狭い線路の空間的周期とがそれぞれ略λ／４の周期で反復されたチョークを構成しており、帯状導体５の長さは略｛（３／４）＋ｎ｝λ（ｎは０以上の整数）に設定され、チョーク型バイアス供給線路４ａと帯状導体５とで共振器を構成している。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記ガンダイオード発振器においては、高周波信号の発振周波数を調整するために誘電体チップ８を帯状導体に近接配置させていたが、誘電体チップ８の位置調整による発振周波数の制御は困難であり、再現性良く発振周波数を微調整することは難しかった。また、誘電体チップ８を手動により位置調整し易いように大型化しようとすると、ガンダイオード発振器全体が大型化し、小型、軽量化ができなくなるという問題点があった。
【０００６】
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、誘電体または金属から成る周波数調整部材を、位置の微調整が容易かつ再現性良くできるよう配置することにより、発振周波数の微調整を再現性良く可能とし、また周波数調整部材を小型化して位置の微調整を可能とすることで高周波ダイオード発振器を小型化することにある。
【０００７】
【課題を解決するための手段】
本発明の高周波ダイオード発振器は、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金属部材を設置し、該金属部材に高周波信号を発振する高周波ダイオードと、幅の広い線路と幅の狭い線路が交互に形成されたチョーク型バイアス供給線路と、該チョーク型バイアス供給線路と前記高周波ダイオード間に架け渡されて直線状に接続する帯状導体とを設けるとともに、前記高周波ダイオードの近傍に配置され前記高周波信号を受信し伝搬させる誘電体線路を設けて成る高周波ダイオード発振器において、前記チョーク型バイアス供給線路の幅の広い線路の周期と幅の狭い線路の周期をそれぞれ略λ／４、前記帯状導体の長さを略｛（３／４）＋ｎ｝λ（ｎは０以上の整数）とし、かつ前記金属部材は帯状導体に対応する位置に形成された孔と、該孔に挿置されかつ金属部材の表面より端部が突出して前記帯状導体に近接する柱状の周波数調整部材とを有することを特徴とする。
【０００８】
本発明は、このような構成により、チョーク型バイアス供給線路と帯状導体とが高周波ダイオードの発振周波数を決定する共振器として機能し、その共振器の帯状導体に周波数調整部材を近接配置して電磁結合させる際に、周波数調整部材の位置を容易かつ再現性良く微調整可能な構成とすることで、前記共振器の実質的な共振器長を微妙に調整でき、その結果発振周波数を再現性良く微調整できるという作用効果を有する。また、周波数調整部材を小型化して位置の微調整を可能とすることで高周波ダイオード発振器全体が小型化される。
【０００９】
【発明の実施の形態】
本発明の高周波ダイオード発振器について以下に説明する。図１〜図４は本発明の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、１はガンダイオード等の高周波ダイオードが発振する高周波信号の空気中での波長λの２分の１以下の間隔で配置した一対の平行平板導体、２はガンダイオード３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、３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、４は金属部材２の一側面に設置され、ガンダイオード３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４ａを形成した配線基板、５はチョーク型バイアス供給線路４ａとガンダイオード３の上部導体とを接続する金属箔リボン等の帯状導体、７はガンダイオード３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である。なお、図１では、内部を透視するために平行平板導体１の上側を一部切り欠いている。
【００１０】
また本発明において、チョーク型バイアス供給線路４ａは、図２に示すように、幅の広い線路の空間的周期と幅の狭い線路の空間的周期とがそれぞれ略λ／４の広狭線路から成り、また帯状導体５の長さは略｛（３／４）＋ｎ｝λ（ｎは０以上の整数）である。この帯状導体５の長さは略３λ／４〜略｛（３／４）＋３｝λが良く、略｛（３／４）＋３｝λを超えると帯状導体５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。
【００１１】
また、略｛（３／４）＋ｎ｝λとしたのは、｛（３／４）＋ｎ｝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５を｛（３／４）＋ｎ｝λよりも１０〜２０％程度長く形成しても良く、その場合、帯状導体５の接するチョーク型バイアス供給線路４ａ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５の長さは｛（３／４）＋ｎ｝λ±２０％程度の範囲内で変化させることができる。
【００１２】
これらチョーク型バイアス供給線路４ａおよび帯状導体５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。
【００１３】
また、帯状導体５は金属部材２の表面から所定間隔をあけて金属部材２と電磁結合しており、チョーク型バイアス供給線路４ａとガンダイオード３間に架け渡されている。即ち、帯状導体５の一端はチョーク型バイアス供給線路４ａの一端に半田付け等により接続され、帯状導体５の他端はガンダイオード３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５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。
【００１４】
そして、金属部材２は、ガンダイオード３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良く、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），Ａｇ，Ａｕ，Ｐｔ等から成る。また金属部材２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良い。
【００１５】
また、誘電体線路７の材料は、コーディエライト（２ＭｇＯ・２Ａｌ2 Ｏ3 ・５ＳｉＯ2 ），アルミナ（Ａｌ2 Ｏ3 ）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３と誘電体線路７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。
【００１６】
本発明の周波数調整部材周辺の部分断面図を図３，図４に示す。これらの図に示すように、金属部材２の帯状導体５に対応する位置に孔９，１１が形成されており、その孔９，１１には柱状の周波数調整部材１０，１２が挿入配置され、かつ金属部材２の表面より周波数調整部材１０，１２の端部が突出して帯状導体５に近接し電磁結合している。これらの孔９，１１は貫通孔であってもよく、その場合金属部材２の帯状導体５と反対側の面より周波数調整部材１０，１２を挿入して、位置調整をすることができ好適である。
【００１７】
また図４の実施形態は、孔１１を内面にネジ切りを施したネジ孔とし、この孔１１にネジ状とされた周波数調整部材１２をネジ込み、回転挿入させて位置の微調整をより微妙に行えるようにしたものである。これにより、さらに微妙な発振周波数の制御が可能となる。これらの周波数調整部材１０，１２は、金属部材２の帯状導体５に対応する位置に複数設けても良く、例えば断面積の大きなものと断面積の小さなものとを設け、断面積の大きなものにより周波数を粗調整し、断面積の小さなものにより周波数を微調整することもできる。
【００１８】
周波数調整部材１０，１２の材料としては、コーディエライト（２ＭｇＯ・２Ａｌ2 Ｏ3 ・５ＳｉＯ2 ），アルミナ（Ａｌ2 Ｏ3 ）等の誘電体、またはＣｕ，Ａｌ，Ｆｅ，ＳＵＳ（ステンレス）等の金属が良く、上記誘電体は高周波信号に対する誘電体損失が小さく、上記金属は加工性に優れる。
【００１９】
このように、周波数調整部材１０，１２を帯状導体５に近接させこれらの間隔を調整することで、帯状導体５と周波数調整部材１０，１２との間の結合容量を変化させ、その結果チョーク型バイアス供給線路４ａと帯状導体５とから成る共振器の実質的な共振器長を微妙に調整できる。例えば、帯状導体５の電気的な共振器長を略｛（３／４）＋ｎ｝λよりも僅かに大きくし、発振周波数を低くすることが可能となる。
【００２０】
そして、周波数調整部材１０，１２と帯状導体５との間隔ｄ（図３）は、０．０５〜０．１０ｍｍとするのが良く、０．０５ｍｍ未満では周波数調整部材１０，１２と帯状導体５とが接触し易くなり、０．１０ｍｍを超えると周波数調整部材１０，１２と帯状導体５とが電磁結合し難くなり、発振周波数の制御が困難になる。
【００２１】
さらに、周波数調整部材１０，１２と帯状導体５との間隔ｄだけでなく、周波数調整部材１０，１２の帯状導体５に対向する端面の面積を調整することによっても、発振周波数の制御が可能であり、前記端面の面積が小さい場合は細かな制御ができるとともに周波数変調可能幅が小さくなり、端面の面積が大きい場合は相対的に粗い制御となり周波数変調可能幅も大きくなる。好ましくは、前記端面の面積は０．１０〜２．０ｍｍ2 が良く、０．１０ｍｍ2 未満では発振周波数の制御が困難であり、２．０ｍｍ2 を超えると、周波数調整部材１０，１２の断面の幅が大きくなり、平行平板導体１と接触し易くなるうえ、帯状導体５よりはみ出した部分は周波数制御に殆ど影響しない。より好ましくは、０．１３〜０．８０ｍｍ2 である。
【００２２】
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。
【００２３】
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。
【００２４】
本発明のＮＲＤガイド用の平行平板導体１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），Ａｇ，Ａｕ，Ｐｔ等の導体板、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】
また、本発明のＮＲＤガイド型の高周波ダイオード発振器は、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ビート信号を得、このビート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。
【００２６】
かくして、本発明は、チョーク型バイアス供給線路と帯状導体とが高周波ダイオードの発振周波数を決定する共振器として機能し、帯状導体に周波数調整部材を近接配置して電磁結合させる際に、周波数調整部材の位置を容易かつ再現性良く微調整可能な構成とすることで、共振器の実質的な共振器長を微妙に調整でき、その結果発振周波数を再現性良く微調整できる。また、周波数調整部材を小型化して位置の微調整を可能とすることで高周波ダイオード発振器全体が小型化される。
【００２７】
尚、本発明は上記実施形態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っても何等差し支えない。
【００２８】
【実施例】
本発明の実施例を以下に説明する。
【００２９】
（実施例）
図１のＮＲＤガイド型のガンダイオード発振器を以下のように構成した。一対の平行平板導体１，１として、縦１００ｍｍ×横１００ｍｍ×厚さ２ｍｍのＡｌ板を１．８ｍｍの間隔で配置し、それらの間にガンダイオード３をネジ止めした真鍮性の金属部材２とコーディエライトセラミックスから成る誘電体線路７を設置した。この金属部材２は高さが約１．８ｍｍの直方体状であり、その一側面には、発振周波数約７７ＧＨｚで波長λが約３．９ｍｍの高周波信号（電磁波）を発振するガンダイオード３と、ガンダイオード３にバイアス電圧を入力するチョーク型バイアス供給線路４ａが形成された配線基板４と、チョーク型バイアス供給線路４ａとガンダイオード３の上部導体とに接続され架け渡された帯状導体５を設けた。
【００３０】
前記配線基板４はガラスエポキシ樹脂から成り、金属部材２に接着剤により固定した。また、チョーク型バイアス供給線路４ａの幅の広い線路と幅の狭い線路について、幅の広い線路の空間的周期はλ／４＝０．７０ｍｍ（誘電体基板上では短波長化する）、幅の狭い線路の空間的周期はλ／４＝０．７０ｍｍであり、幅の広い線路部の幅は１．５ｍｍ、幅の狭い線路部の幅は０．２ｍｍである。帯状導体５は厚さ３５μｍ，幅０．６ｍｍ，長さ３．２ｍｍの銅箔リボンから成り、一端をチョーク型バイアス供給線路４ａに他端をガンダイオード３の上部導体に各々半田付けした。誘電体線路７は、比誘電率５のコーディエライトセラミックスから成り、ガンダイオード３の上部導体から約０．５ｍｍの間隔をあけて配置した。
【００３１】
そして、図３に示すように、ガンダイオード３の上部導体端部Ｒと、配線基板４と帯状導体５との接続点Ｐとの中間点Ｑに対応する金属部材２の位置に、直径０．８ｍｍの貫通孔９を形成し、この貫通孔９に直径０．８ｍｍ，端面の面積が約０．５ｍｍ2 ，比誘電率５のコーディエライトセラミックスから成る柱状の周波数調整部材１０を挿入配置し、ガンダイオード発振器を作製した。
【００３２】
このガンダイオード発振器について、周波数調整部材１０の端部を金属部材２表面から突出させない場合、即ち周波数調整部材１０と帯状導体５とを容量結合させない状態では、発振周波数は７６．２４９ＧＨｚであったものが、周波数調整部材１０の端部を金属部材２表面から突出させ周波数調整部材１０と帯状導体５との間隔ｄを０．０５ｍｍとした場合、発振周波数は７５．９０４ＧＨｚに変化した。従って、発振周波数を３４５ＭＨｚ低下させることができ、また間隔ｄを調整することで再現性良く発振周波数を制御できた。
【００３３】
【発明の効果】
本発明は、チョーク型バイアス供給線路の幅の広い線路の周期と幅の狭い線路の周期をそれぞれ略λ／４、帯状導体の長さを略｛（３／４）＋ｎ｝λ（ｎは０以上の整数）とし、かつ金属部材は帯状導体に対応する位置に形成された孔と、孔に挿置されかつ金属部材の表面より端部が突出して帯状導体に近接する柱状の周波数調整部材とを有することにより、チョーク型バイアス供給線路と帯状導体とが高周波ダイオードの発振周波数を決定する共振器として機能し、帯状導体に周波数調整部材を近接配置して電磁結合させる際に、周波数調整部材の位置を容易かつ再現性良く微調整可能とすることで、共振器の実質的な共振器長を微妙に調整でき、その結果発振周波数を再現性良く微調整できる。また、周波数調整部材を小型化して位置の微調整を可能とすることで高周波ダイオード発振器全体が小型化される。
【図面の簡単な説明】
【図１】本発明のＮＲＤガイド型の高周波ダイオード発振器の内部を透視した斜視図である。
【図２】本発明の高周波ダイオード発振器用のチョーク型バイアス供給線路および帯状導体の平面図である。
【図３】本発明の高周波ダイオード発振器を示し、周波数調整部材周辺の部分断面図である。
【図４】本発明の高周波ダイオード発振器の他の実施形態を示し、周波数調整部材周辺の部分断面図である。
【図５】従来のＮＲＤガイド型の高周波ダイオード発振器の内部を透視した斜視図である。
【符号の説明】
１：平行平板導体
２：金属部材
３：ガンダイオード
４：配線基板
４ａ：チョーク型バイアス供給線路
５：帯状導体
７：誘電体線路
９：孔
１０：周波数調整部材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-frequency diode oscillator such as a Gunn diode oscillator incorporated in a high-frequency circuit such as a millimeter-wave integrated circuit, and relates to a non-radiative dielectric line type high-frequency diode oscillator having an oscillation frequency adjustment function.
[0002]
[Prior art]
A conventional Gunn diode oscillator is shown in FIG. In the figure, reference numeral 1 denotes a pair of parallel plate conductors, and the interval z between them is set to z ≦ λ / 2, thereby eliminating noise from entering the dielectric line 7 from the outside and radiating high-frequency signals to the outside. A so-called non-radiative dielectric waveguide (hereinafter referred to as an NRD guide) that transmits a signal without being formed is configured. Note that λ is the wavelength of an electromagnetic wave (high frequency signal) propagating in the air at the operating frequency.
[0003]
Further, 2 is a metal member such as a substantially rectangular parallelepiped metal block for mounting (mounting) the Gunn diode, 3 is a Gunn diode which is a kind of high-frequency diode that oscillates microwaves and millimeter waves, and 4 is a metal member 2. The wiring board 5 is provided with a choke-type bias supply line 4a that functions as a low-pass filter that supplies a bias voltage to the Gunn diode 3 and prevents leakage of high-frequency signals. A band-shaped conductor such as a metal foil ribbon connecting the upper conductor of the diode 3, 7 is a dielectric line that is disposed in the vicinity of the Gunn diode 3 and receives a high-frequency signal and propagates it to the outside. In FIG. 5, a part of the upper side of the parallel plate conductor 1 is cut away to allow the inside to be seen through. Further, the strip-shaped conductor 5 is bridged between the choke-type bias supply line 4 a and the Gunn diode 3 at a predetermined interval from the surface of the metal member 2.
[0004]
Then, the present application is to make it possible to control the oscillation frequency of a high-frequency signal by placing a substantially quadrangular prism-shaped dielectric chip 8 having a main surface parallel to the main surface of the strip-shaped conductor 5 in close proximity to the strip-shaped conductor 5 and electromagnetically coupling it. The person previously proposed (Japanese Patent Application No. 11-237318). In this case, the choke-type bias supply line 4a constitutes a choke in which the spatial period of the wide line and the spatial period of the narrow line are respectively repeated at a period of approximately λ / 4. The length of the strip conductor 5 is set to approximately {(3/4) + n} λ (n is an integer equal to or greater than 0), and the choke bias supply line 4a and the strip conductor 5 constitute a resonator.
[0005]
[Problems to be solved by the invention]
However, in the Gunn diode oscillator, the dielectric chip 8 is disposed close to the strip conductor to adjust the oscillation frequency of the high frequency signal. However, it is difficult to control the oscillation frequency by adjusting the position of the dielectric chip 8. It was difficult to fine tune the oscillation frequency with good reproducibility. Further, if the dielectric chip 8 is to be increased in size so that the position thereof can be easily adjusted manually, there is a problem that the entire Gunn diode oscillator is increased in size and cannot be reduced in size and weight.
[0006]
Accordingly, the present invention has been completed in view of the above circumstances, and its purpose is to oscillate by arranging a frequency adjusting member made of a dielectric or metal so that fine adjustment of the position can be easily performed with good reproducibility. An object of the present invention is to reduce the size of the high-frequency diode oscillator by enabling fine adjustment of the frequency with high reproducibility and by making the frequency adjustment member small and finely adjusting the position.
[0007]
[Means for Solving the Problems]
The high-frequency diode oscillator according to the present invention includes a high-frequency diode that oscillates a high-frequency signal on a metal member provided between parallel plate conductors arranged at intervals of 1/2 or less of the wavelength λ of the high-frequency signal, A choke-type bias supply line in which a wide line and a narrow line are alternately formed; and a strip-shaped conductor that is bridged between the choke-type bias supply line and the high-frequency diode and is connected in a straight line; In a high-frequency diode oscillator provided with a dielectric line disposed near a diode for receiving and propagating the high-frequency signal, the period of the wide line and the period of the narrow line of the choke-type bias supply line are approximately λ, respectively. / 4, the length of the strip conductor is approximately {(3/4) + n} λ (n is an integer of 0 or more), and the metal member corresponds to the strip conductor. And having a hole formed in location, and a columnar frequency adjusting member end portion from the surface of the interposed by and metal member in the hole is close to the strip conductor protrudes.
[0008]
With this configuration, the present invention functions as a resonator in which the choke-type bias supply line and the strip conductor determine the oscillation frequency of the high-frequency diode, and an electromagnetic wave is disposed by placing a frequency adjusting member in proximity to the strip conductor of the resonator. When coupling, the position of the frequency adjustment member can be easily and finely adjusted, so that the substantial resonator length of the resonator can be finely adjusted. As a result, the oscillation frequency can be adjusted with good reproducibility. The effect is that fine adjustment is possible. Further, the entire high-frequency diode oscillator can be miniaturized by miniaturizing the frequency adjusting member to enable fine adjustment of the position.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The high-frequency diode oscillator of the present invention will be described below. 1 to 4 show NRD guide type high-frequency diode oscillators according to the present invention. In these drawings, reference numeral 1 denotes a half or less of a wavelength λ in air of a high-frequency signal oscillated by a high-frequency diode such as a Gunn diode. A pair of parallel plate conductors arranged at intervals of 2, 2 is a metal member such as a substantially rectangular parallelepiped metal block for mounting (mounting) the Gunn diode 3, and 3 is a type of high-frequency diode that oscillates microwaves and millimeter waves The Gunn diode 4 is installed on one side of the metal member 2 and is a wiring board on which a choke-type bias supply line 4a that functions as a low-pass filter that supplies a bias voltage to the Gunn diode 3 and prevents leakage of high-frequency signals, 5 is a strip conductor such as a metal foil ribbon that connects the choke-type bias supply line 4a and the upper conductor of the Gunn diode 3, and 7 is a gun. Disposed in the vicinity of the diode 3 is dielectric waveguide which propagates to the outside and receives a high frequency signal. In FIG. 1, a part of the upper side of the parallel plate conductor 1 is notched in order to see through the inside.
[0010]
In the present invention, as shown in FIG. 2, the choke-type bias supply line 4a is composed of wide and narrow lines in which the spatial period of the wide line and the spatial period of the narrow line are approximately λ / 4, The length of the strip-shaped conductor 5 is approximately {(3/4) + n} λ (n is an integer of 0 or more). The length of the strip-shaped conductor 5 is preferably approximately 3λ / 4 to approximately {(3/4) +3} λ. If the length exceeds approximately {(3/4) +3} λ, the strip-shaped conductor 5 becomes long, and is bent, twisted, or the like. As a result, the variation in characteristics such as the oscillation frequency among individual high-frequency diode oscillators increases, and various resonance modes are generated, thereby generating a signal having a frequency different from the desired oscillation frequency. More preferably, it is approximately 3λ / 4, approximately {(3/4) +1} λ.
[0011]
Further, the reason why it is substantially {(3/4) + n} λ is that resonance is possible even if it is slightly deviated from {(3/4) + n} λ. For example, the strip conductor 5 may be formed to be approximately 10 to 20% longer than {(3/4) + n} λ, and in this case, the length of the first pattern of the choke-type bias supply line 4a with which the strip conductor 5 is in contact. This is because a part of λ / 4 is considered to contribute to resonance. Therefore, the length of the strip-shaped conductor 5 can be changed within a range of about {(3/4) + n} λ ± 20%.
[0012]
The choke-type bias supply line 4a and the strip conductor 5 are made of Cu, Al, Au, Ag, W, Ti, Ni, Cr, Pd, Pt, etc., and particularly Cu and Ag have good electrical conductivity. It is preferable in that it has a small loss and a large oscillation output.
[0013]
The strip-shaped conductor 5 is electromagnetically coupled to the metal member 2 at a predetermined interval from the surface of the metal member 2, and is stretched between the choke-type bias supply line 4 a and the Gunn diode 3. That is, one end of the strip conductor 5 is connected to one end of the choke-type bias supply line 4a by soldering or the like, and the other end of the strip conductor 5 is connected to the upper conductor of the Gunn diode 3 by soldering or the like. The middle part except for the connection part of is floating in the air.
[0014]
The metal member 2 may be a metal conductor because it also serves as an electrical ground (earth) of the Gunn diode 3, and the material is not particularly limited as long as the material is a metal (including alloy) conductor. It consists of brass (brass: Cu—Zn alloy), Al, Cu, SUS (stainless steel), Ag, Au, Pt, and the like. Also, the metal member 2 is a metal block made entirely of metal, a surface of an insulating base such as ceramics or plastic that is partially metal-plated, or a surface of the insulating base that is partially or partially coated with a conductive resin material. It may be a thing.
[0015]
The material of the dielectric line 7 is preferably cordierite (2MgO · 2Al 2 O 3 · 5SiO 2 ), alumina (Al 2 O 3 ), etc., and these have low loss in the high frequency band. The distance between the Gunn diode 3 and the dielectric line 7 is preferably about 1.0 mm or less, and if it exceeds 1.0 mm, the loss is reduced and the maximum separation width capable of electromagnetic coupling is exceeded.
[0016]
3 and 4 are partial cross-sectional views around the frequency adjusting member of the present invention. As shown in these drawings, holes 9 and 11 are formed at positions corresponding to the strip-shaped conductor 5 of the metal member 2, and columnar frequency adjusting members 10 and 12 are inserted and arranged in the holes 9 and 11, Further, the end portions of the frequency adjusting members 10 and 12 protrude from the surface of the metal member 2 and are close to the band-shaped conductor 5 and are electromagnetically coupled. These holes 9 and 11 may be through holes. In this case, the frequency adjusting members 10 and 12 are inserted from the surface of the metal member 2 on the side opposite to the band-like conductor 5 so that the position can be adjusted. is there.
[0017]
In the embodiment of FIG. 4, the hole 11 is a screw hole whose inner surface is threaded, and a screw-shaped frequency adjusting member 12 is screwed into the hole 11 to be rotated and inserted to finely adjust the position. It is something that can be done. This makes it possible to control the oscillation frequency more delicately. A plurality of these frequency adjusting members 10 and 12 may be provided at positions corresponding to the strip-like conductor 5 of the metal member 2. For example, a member having a large cross-sectional area and a member having a small cross-sectional area are provided. It is also possible to coarsely adjust the frequency and finely adjust the frequency with a small cross-sectional area.
[0018]
As a material of the frequency adjusting members 10 and 12, a dielectric such as cordierite (2MgO · 2Al 2 O 3 · 5SiO 2 ), alumina (Al 2 O 3 ), Cu, Al, Fe, SUS (stainless steel), or the like The metal is good, and the dielectric has a low dielectric loss for high-frequency signals, and the metal is excellent in workability.
[0019]
Thus, the frequency adjusting members 10 and 12 are brought close to the strip conductor 5 and the distance between them is adjusted, thereby changing the coupling capacitance between the strip conductor 5 and the frequency adjusting members 10 and 12, and as a result, choke type. The substantial resonator length of the resonator composed of the bias supply line 4a and the strip conductor 5 can be finely adjusted. For example, the electrical resonator length of the strip conductor 5 can be made slightly larger than approximately {(3/4) + n} λ, and the oscillation frequency can be lowered.
[0020]
The distance d (FIG. 3) between the frequency adjusting members 10 and 12 and the strip-shaped conductor 5 is preferably 0.05 to 0.10 mm, and if less than 0.05 mm, the frequency adjusting members 10 and 12 and the strip-shaped conductor 5 are used. If it exceeds 0.10 mm, it becomes difficult for the frequency adjusting members 10 and 12 and the strip-shaped conductor 5 to be electromagnetically coupled, and it becomes difficult to control the oscillation frequency.
[0021]
Furthermore, the oscillation frequency can be controlled not only by adjusting the distance d between the frequency adjusting members 10 and 12 and the strip conductor 5 but also by adjusting the area of the end face of the frequency adjusting members 10 and 12 facing the strip conductor 5. In addition, when the area of the end face is small, fine control can be performed and the frequency modulation possible width becomes small. When the area of the end face is large, the control becomes relatively rough and the frequency modulation possible width becomes large. Preferably, the area of the end face may have 0.10～2.0Mm 2, is less than 0.10 mm 2 is difficult to control the oscillation frequency, exceeds 2.0 mm 2, the cross section of the frequency adjusting members 10 and 12 And the portion protruding from the strip-shaped conductor 5 hardly affects the frequency control. More preferably, it is 0.13-0.80 mm < 2 >.
[0022]
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 GHz, and for example, a high frequency band of 30 GHz or higher, particularly 50 GHz or higher, and more preferably 70 GHz or higher is preferable.
[0023]
As the high-frequency diode of the present invention, microwave diodes such as impatt (impact ionization avalanche transit time) diodes, trapatts (trapatt: trapped plasma avalanche triggered transit) diodes, Gunn diodes, and millimeter wave diodes are preferably used. Is done.
[0024]
The parallel plate conductor 1 for NRD guide of the present invention is a conductor plate such as Cu, Al, Fe, SUS (stainless steel), Ag, Au, Pt, ceramics, resin, etc. in terms of high electrical conductivity and workability. These conductor layers may be formed on the surface of an insulating plate made of or the like.
[0025]
The NRD guide type high-frequency diode oscillator of the present invention is used for a wireless LAN, a millimeter wave radar of an automobile, and the like, for example, irradiates obstacles around the automobile and other automobiles with millimeter waves, By synthesizing the reflected wave with the original millimeter wave, a beat signal is obtained, and by analyzing this beat signal, the distance to obstacles and other automobiles, the moving speed thereof, and the like can be measured.
[0026]
Thus, according to the present invention, the choke-type bias supply line and the strip conductor function as a resonator that determines the oscillation frequency of the high-frequency diode. By making the position of the structure easy and finely adjustable with good reproducibility, the substantial resonator length of the resonator can be finely adjusted, and as a result, the oscillation frequency can be finely adjusted with good reproducibility. Further, the entire high-frequency diode oscillator can be miniaturized by miniaturizing the frequency adjusting member to enable fine adjustment of the position.
[0027]
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.
[0028]
【Example】
Examples of the present invention will be described below.
[0029]
(Example)
The NRD guide type Gunn diode oscillator of FIG. 1 was configured as follows. As a pair of parallel plate conductors 1, a brass metal member 2 in which Al plates having a length of 100 mm × width of 100 mm × thickness of 2 mm are arranged at intervals of 1.8 mm, and a Gunn diode 3 is screwed between them, A dielectric line 7 made of cordierite ceramics was installed. The metal member 2 has a rectangular parallelepiped shape with a height of about 1.8 mm, and on one side thereof, a Gunn diode 3 that oscillates a high-frequency signal (electromagnetic wave) having an oscillation frequency of about 77 GHz and a wavelength λ of about 3.9 mm, A wiring board 4 on which a choke-type bias supply line 4a for inputting a bias voltage to the Gunn diode 3 is formed, and a strip-like conductor 5 connected to the choke-type bias supply line 4a and the upper conductor of the Gunn diode 3 is provided. It was.
[0030]
The wiring board 4 is made of glass epoxy resin and fixed to the metal member 2 with an adhesive. In addition, for the wide line and the narrow line of the choke-type bias supply line 4a, the spatial period of the wide line is λ / 4 = 0.70 mm (shorter wavelength on the dielectric substrate), The spatial period of the narrow line is λ / 4 = 0.70 mm, the width of the wide line part is 1.5 mm, and the width of the narrow line part is 0.2 mm. The strip-shaped conductor 5 is made of a copper foil ribbon having a thickness of 35 μm, a width of 0.6 mm, and a length of 3.2 mm. One end is soldered to the choke-type bias supply line 4 a and the other end is soldered to the upper conductor of the Gunn diode 3. The dielectric line 7 is made of cordierite ceramics having a relative dielectric constant of 5, and is arranged at an interval of about 0.5 mm from the upper conductor of the Gunn diode 3.
[0031]
As shown in FIG. 3, the diameter of the metal member 2 corresponding to the intermediate point Q between the upper conductor end R of the Gunn diode 3 and the connection point P between the wiring substrate 4 and the strip-shaped conductor 5 is 0. An 8 mm through hole 9 is formed, and a columnar frequency adjusting member 10 made of cordierite ceramics having a diameter of 0.8 mm, an end face area of about 0.5 mm 2 and a relative dielectric constant of 5 is inserted and disposed in the through hole 9. A Gunn diode oscillator was manufactured.
[0032]
In this Gunn diode oscillator, when the end of the frequency adjusting member 10 is not protruded from the surface of the metal member 2, that is, when the frequency adjusting member 10 and the strip conductor 5 are not capacitively coupled, the oscillation frequency is 76.249 GHz. However, when the end of the frequency adjusting member 10 protrudes from the surface of the metal member 2 and the distance d between the frequency adjusting member 10 and the strip conductor 5 is 0.05 mm, the oscillation frequency is changed to 75.904 GHz. Therefore, the oscillation frequency can be lowered by 345 MHz, and the oscillation frequency can be controlled with good reproducibility by adjusting the interval d.
[0033]
【The invention's effect】
In the present invention, the choke-type bias supply line has a wide line period and a narrow line period of approximately λ / 4, and the strip conductor has a length of approximately {(3/4) + n} λ (n is 0). And a metal member is a hole formed at a position corresponding to the band-shaped conductor, and a columnar frequency adjusting member that is inserted into the hole and protrudes from the surface of the metal member and close to the band-shaped conductor. The choke-type bias supply line and the strip conductor function as a resonator that determines the oscillation frequency of the high-frequency diode, and when the frequency adjustment member is disposed close to the strip conductor and electromagnetically coupled, By making the position easy and finely adjustable, the substantial resonator length of the resonator can be finely adjusted, and as a result, the oscillation frequency can be finely adjusted with good repeatability. Further, the entire high frequency diode oscillator can be miniaturized by miniaturizing the frequency adjusting member to enable fine adjustment of the position.
[Brief description of the drawings]
FIG. 1 is a perspective view of the inside of an NRD guide type high-frequency diode oscillator according to the present invention.
FIG. 2 is a plan view of a choke-type bias supply line and a strip conductor for a high-frequency diode oscillator according to the present invention.
FIG. 3 shows a high-frequency diode oscillator according to the present invention and is a partial cross-sectional view around a frequency adjusting member.
FIG. 4 shows another embodiment of the high-frequency diode oscillator of the present invention, and is a partial cross-sectional view around the frequency adjusting member.
FIG. 5 is a perspective view of the inside of a conventional NRD guide type high frequency diode oscillator.
[Explanation of symbols]
1: Parallel plate conductor 2: Metal member 3: Gunn diode 4: Wiring board 4a: Choke-type bias supply line 5: Strip conductor 7: Dielectric line 9: Hole 10: Frequency adjusting member