JP2004260398A - Array antenna device and its control method and device - Google Patents

Abstract

An array antenna device capable of changing the polarization of a radio signal to be transmitted and received is provided.
An array antenna device includes an excitation element for transmitting and receiving a radio signal, six non-excitation elements provided at a predetermined distance from the excitation element, and each non-excitation element. And six variable reactance elements 12-1 to 12-6 connected to A1 to A6, respectively, wherein at least one parasitic element is changed to a director or a reflector by changing the reactance value of each variable reactance element. To change the directional characteristics. Each of the non-excitation elements A1 to A6 is provided so as to be inclined with respect to the excitation element A0, and transmits and receives a radio signal of a horizontal polarization component in addition to a vertical polarization component. The polarization of the array antenna apparatus 100 is changed by controlling the vertical polarization component and the horizontal polarization component of the radio signal by changing the polarization.
[Selection diagram] Fig. 1

Description

【００３７】
ここで、βは伝搬定数２π／λであり、ｄはアンテナ素子の間隔であって、本実施形態ではλ／４であり、さらに、
【数３】
φ_ｍ＝２π（ｍ−１）／６
ｍ＝１，…，６
である。
【００３８】
この信号モデルによれば、アレーアンテナ装置１００で受信された受信信号ｙ（ｔ）を次のように表すことができる。
【００３９】
【数４】
ｙ（ｔ）＝ｉ^Ｔｓ（ｔ）＝ｉ^Ｔａ（θ，φ）ｕ（ｔ）
【００４０】
ここで、ベクトルｉ＝［ｉ_０，ｉ_１，…，ｉ_６］^Ｔはアレーアンテナ装置１００の高周波電流ベクトルであり、各素子上の信号を観測可能な従来のアレーアンテナにおけるウエイトベクトルと同様の役割を果たし、本実施形態では「等価ウエイトベクトル」と呼ぶ。等価ウエイトベクトルｉは、次のように定式化される。
【００４１】
【数５】

又は
【数６】
ｉ＝（Ｙ^−１＋Ｘ）^−１［ｖ_ｓ，０，…，０］^Ｔ
【００４２】
ここで、ｖ_ｓは給電電圧を表す定数であり、Ｚｓはアレーアンテナ装置１００の出力インピーダンスを表す定数である。対角行列Ｘはリアクタンス行列と呼ばれ、アレーアンテナ装置１００の出力インピーダンスＺｓと、虚数単位ｊを乗算された可変リアクタンス素子のリアクタンス値Ｘｍ（ｍ＝１，…，６）とを成分とする行列である。さらに数５において、Ｙ＝［Ｙ_ｋｌ］_{（６＋１）×（６＋１）}はアドミタンス行列と呼ばれ、その要素Ｙ_ｋｌはアレーアンテナ装置１００の素子Ａｋと素子Ａｌ（０≦ｋ，ｌ≦６）の間の相互アドミタンス要素を表す。アドミタンス要素Ｙ_ｋｌの値には、公知の相反定理により、通常型のアレーアンテナ装置と同様にＹ_ｋｌ＝Ｙ_ｌｋが成り立つ。アドミタンス要素Ｙ_ｋｌの値はまた、例えば半径、空間の間隔及び素子の長さといったアンテナの物理的構造に依存して一定であり、さらに、アレーアンテナ装置１００の回転対称性より、次の関係を満たす。
【００４３】
【数７】
Ｙ_１１＝Ｙ_２２＝Ｙ_３３＝Ｙ_４４＝Ｙ_５５＝Ｙ_６６
【数８】
Ｙ_０１＝Ｙ_０２＝Ｙ_０３＝Ｙ_０４＝Ｙ_０５＝Ｙ_０６
【数９】
Ｙ_１２＝Ｙ_２３＝Ｙ_３４＝Ｙ_４５＝Ｙ_５６＝Ｙ_６１
【数１０】
Ｙ_１３＝Ｙ_２４＝Ｙ_３５＝Ｙ_４６＝Ｙ_５１＝Ｙ_６２
【数１１】
Ｙ_１４＝Ｙ_２５＝Ｙ_３６
【００４４】
ゆえに、アドミタンス行列Ｙは、アドミタンス要素の６個の成分Ｙ_００，Ｙ_１０，Ｙ_１１，Ｙ_２１，Ｙ_３１及びＹ_４１のみによって決定されることがわかる。以下、説明の簡単化のために、アレーアンテナ装置１００から出力される受信信号と、Ａ／Ｄ変換器３から出力される受信信号とを同一視して、ｙ（ｔ）で表す。
【００４５】
次に、アレーアンテナ装置１００の各アンテナ素子に係るベクトル実効長の概念を導入し、このベクトル実効長がベクトルの性質と方向依存性とを有することについて説明する。
【００４６】
本実施形態のアレーアンテナ装置１００、及び特許文献１に開示されたようなアレーアンテナ装置は通常のアレーアンテナと異なり、各アンテナ素子上に励振される電流を直接制御できず、リアクタンス値によって実現可能な電流のアレー配列（等価ウェイトベクトル）が明確でないため、所望の指向特性や偏波を実現するリアクタンス値を解析的に求めることは困難である。そこで、最急勾配法を用いた反復による収束解を用いる。そのためには、等価ウェイトベクトル表現（非特許文献２及び３を参照）が便利であるので、本実施形態のアレーアンテナ装置１００に対して定式化を行う。
【００４７】
アンテナ素子Ａｍ（ｍ＝０，１，…，６）のポート（本実施形態では、各アンテナ素子の長手方向の中央部に位置し、１対のアンテナ素子の給電点のポートをいう。）に流れる電流ｉ_ｍは給電線路や可変リアクタンス素子１２−ｍ等の回路素子に流れる電流に等しいので、信号処理やリアクタンス制御にとって重要な値である。また、この電流ｉ_ｍは回路理論により計算可能である。この電流ｉ_ｍを成分とするベクトルを等価ウェイトベクトルｉとし、等価ウエイトベクトルｉとステアリングベクトルａ（θ，φ）との積によりアレーファクタ（すなわちアレーアンテナ装置１００の指向特性）Ｅ（θ，φ）を計算してきた（非特許文献２及び３を参照）。しかしながら、電波は、送信時には、ポート電流ｉ_ｍからだけではなくアンテナ素子上に流れる電流全体により放射され、また、受信時にも同様に、到来した電波はアンテナ素子全体に流れる電流を発生させる。アンテナ素子Ａｍ上の電流分布（大きさ、位相と形状）は、ベクトル実効長ｌｅ_ｍにより表現することができる。なお、可変リアクタンス素子が装荷されていないアンテナ素子のベクトル実効長ｌｅ_ｍ ^（０）は、各アンテナ素子Ａｍの物理長Ｌｍにほぼ比例したγ×Ｌｍで表すことができる。ここで、比例定数γは約０．６５である。比例定数γは正確にはアンテナ構造に依存するが、大きく変化しない。ここで、新たに、各アンテナ素子Ａｍに流れる電流ｉ’_ｍを数１２で表す。
【００４８】
【数１２】
ｉ’_ｍ＝ｌｅ_ｍｉ_ｍ
【００４９】
ｉ’_ｍを成分とする新たな等価ウェイトベクトルをｉ’で表すと、アレーファクタＥ（θ，φ）は数１３で計算される。
【００５０】
【数１３】
Ｅ（θ，φ）＝ａ^Ｔ（θ，φ）ｉ’
【００５１】
非特許文献４及び５において、ベクトル実効長ｌｅ_ｍは一定でなくアンテナ素子毎に変化するということが示され、非特許文献６において、ベクトル実効長ｌｅ_ｍは、ポート電流ｉ_ｍと電圧ｖ_ｍを用いて数１４のように表現できるということが示された。
【００５２】
【数１４】
ｌｅ_ｍ＝ｌｅ_ｍ ^（０）（１−ｊα_ｍｖ_ｍ／ｉ_ｍ）
【００５３】
ｌｅ_ｍ ^（０）はポートに何も接続しない場合のベクトル実効長であり、α_ｍは比例定数である。数１４において、ベクトル実効長ｌｅ_ｍは電流の強さと位相を表す複素スカラ量である。しかし、一般にベクトル実効長は実空間におけるベクトル量であり、また、方向依存性を有する。このように、数１２、数１４のベクトル実効長ｌｅ_ｍを複素スカラ量から、方向依存性を有するベクトル量に拡張するによって、図１のような偏波を変化させることができるアレーアンテナ装置１００を表現できる。
【００５４】
そこで、図３に示したように、各非励振素子Ａ１乃至Ａ６のベクトル実効長ｌｅ_ｍを、ｚ軸に平行な垂直成分ｌｅ_ｍ ^Ｖと、ｚ軸に直交する水平成分ｌｅ_ｍ ^Ｈとに分けて考える。これらのベクトルは実空間におけるベクトルであり、等価ウェイトベクトルｉ’等におけるアンテナ素子のアレー配列を表すベクトルとは異なる。図３のように、非励振素子Ａｍが鉛直方向となす傾斜角ωを有するとすると、ベクトル実効長の垂直成分ｌｅ_ｍ ^Ｖと水平成分ｌｅ_ｍ ^Ｈは、各非励振素子Ａｍの正面方向である仰角θ＝９０、方位角φ＝φ_ｍにおいて、数１５及び数１６のように表される。
【００５５】
【数１５】
ｌｅ_ｍ ^Ｖ＝ｌｅ_ｍｃｏｓω
【数１６】
ｌｅ_ｍ ^Ｈ＝ｌｅ_ｍｓｉｎω
【００５６】
また、ベクトル実効長の方向（θ，φ）に対する依存性は、ベクトル実効長の垂直成分と水平成分とで異なり、数１７及び数１８のように表される。
【００５７】
【数１７】
ｌｅ_ｍ ^Ｖ（θ，φ）＝ｌｅ_ｍ ^Ｖｆ_ｍ（θ−９０）
【数１８】
ｌｅ_ｍ ^Ｈ（θ，φ）＝ｌｅ_ｍ ^Ｈｆ_ｍ（φ−φ_ｍ）
【００５８】
ここで、ｆ_ｍ（ξ）は素子パターンを表し、アンテナ素子長が約半波長以下に短い場合、数１９で近似できる。
【００５９】
【数１９】
ｆ_ｍ（ξ）≒ｃｏｓ（ξ）
【００６０】
従って、各非励振素子Ａｍのベクトル実効長の垂直成分ｌｅ_ｍ ^Ｖ（θ，φ）は、ベクトル実効長ｌｅ_ｍに基づいて当該アレーアンテナの仰角の関数ｆ_ｍ（θ−９０）を用いて計算され、各非励振素子Ａｍのベクトル実効長の水平成分ｌｅ_ｍ ^Ｈ（θ，φ）は、ベクトル実効長ｌｅ_ｍに基づいて、当該アレーアンテナの方位角の関数ｆ_ｍ（φ−φ_ｍ）を用いて計算される。
【００６１】
図３６に図示された従来技術のアレーアンテナ装置１５０や、非特許文献４，５及び９に記載されたアレーアンテナ装置では、鉛直方向からのアンテナ素子の傾斜角ωが０であったため、数１６より水平偏波成分が存在しないので、ベクトル実効長をスカラ量ｌｅ_ｍ＝ｌｅ_ｍ ^Ｖとして扱うことができた。また、数１７及び数１９から分かるように、方位角（θ，φ）に対するベクトル実効長の依存性は全てのアンテナ素子で同一なので、素子パターンｆ_ｍ（θ−９０）をまとめて別に考えることができた。さらには、ベクトル実効長ｌｅ_ｍがアンテナ素子によらず一定と考えたので、ベクトル実効長ｌｅ_ｍすなわち素子パターンを考慮せず、アレーファクタを計算していた（非特許文献２を参照）。一方、上記で考察したように、ベクトル実効長の水平偏波成分ｌｅ_ｍ ^Ｈ（θ，φ）は、アンテナ素子の向きが変わるため、数１８のようにアンテナ素子Ａｍにより方位角φに対する依存性が異なることが特徴である。
【００６２】
以上の説明によれば、数１７のベクトル実効長の垂直成分ｌｅ_ｍ ^Ｖ（θ，φ）で補正された等価ウエイトベクトルの垂直成分をｉ^Ｖで表し、数１８のベクトル実効長の水平成分ｌｅ_ｍ ^Ｈ（θ，φ）で補正された等価ウエイトベクトルの水平成分をｉ^Ｈで表すことができ、数４の受信信号ｙ（ｔ）の式は次のように変形される。
【００６３】
【数２０】
ｙ（ｔ）＝｛（ｉ^Ｖ＋ｉ^Ｈ）^Ｔａ（θ，φ）｝×ｕ（ｔ）
＝｛（ｉ^Ｖ）^Ｔａ（θ，φ）｝×ｕ（ｔ）
＋｛（ｉ^Ｈ）^Ｔａ（θ，φ）｝×ｕ（ｔ）
＝Ｅ^Ｖ×ｕ（ｔ）＋Ｅ^Ｈ×ｕ（ｔ）
【００６４】
ここで、Ｅ^Ｖ＝｛（ｉ^Ｖ）^Ｔａ（θ，φ）｝はアレーファクタの垂直成分を表し、Ｅ^Ｈ＝｛（ｉ^Ｈ）^Ｔａ（θ，φ）｝はアレーファクタの水平成分を表す。従って、数１３のアレーファクタＥ（θ，φ）は、次式のように垂直成分Ｅ^Ｖと水平成分Ｅ^Ｈとの和として表すことができる。
【００６５】
【数２１】
Ｅ（θ，φ）＝Ｅ^Ｖ＋Ｅ^Ｈ
【００６６】
以下、アレーファクタの垂直成分Ｅ^Ｖを、アレーアンテナ装置１００の電界の垂直成分と呼び、アレーファクタの水平成分Ｅ^Ｈを、アレーアンテナ装置１００の電界の水平成分と呼ぶことができる。従って、前者はアレーアンテナ装置１００の垂直面内の指向特性であり、後者はその水平面内の指向特性である。すなわち、以下の手順を用いて、当該アレーアンテナ装置１００の指向特性を計算できる。
【００６７】
（１）アレーアンテナ装置１００における励振素子Ａ０と各非励振素子Ａ１乃至Ａ６からなる各素子（これら７本の素子をいう。）Ａ０乃至Ａ７間のアドミタンスからなるアドミタンス行列Ｙと、各可変リアクタンス素子１２−１乃至１２−６のリアクタンス値からなるリアクタンス行列Ｘとに基づいて、数５を用いて、各素子Ａ０乃至Ａ７に流れる電流のアレー分布の等価ウエイトベクトルｉを計算する。
（２）各可変リアクタンス素子１２−１乃至１２−６が装荷されないときの各素子Ａ０乃至Ａ７のベクトル実効長ｌｅ_ｍ ^（０）と、各可変リアクタンス素子１２−１乃至１２−６上のポート電流及びポート電圧とに基づいて、上記数１４を用いて、各素子Ａ０乃至Ａ７のベクトル実効長ｌｅ_ｍを計算する。
（３）計算された各素子Ａ０乃至Ａ７のベクトル実効長ｌｅ_ｍに基づいて、各素子Ａ０乃至Ａ７のベクトル実効長ｌｅ_ｍと、励振素子Ａ０に対する各非励振素子Ａ１乃至Ａ７の傾斜角ωと、励振素子Ａ０と平行な方向からの傾斜角である仰角φと、非励振素子Ａ０と直交する面での方位角θとの関係を示す式（上記数１５乃至数１９）を用いて、各素子Ａ０乃至Ａ７に関する、励振素子Ａ０と平行なベクトル実効長の成分ｌｅ_ｍ ^Ｖ（θ，φ）と、励振素子Ａ０と直交するベクトル実効長の成分ｌｅ_ｍ ^Ｈ（θ，φ）とを計算する。
（４）計算された各素子Ａ０乃至Ａ７に関する、励振素子Ａ０と平行なベクトル実効長の成分ｌｅ_ｍ ^Ｖ（θ，φ）と、励振素子Ａ０と直交するベクトル実効長の成分ｌｅ_ｍ ^Ｈ（θ，φ）とに対して、計算された等価ウエイトベクトルｉを乗算しかつアレーアンテナ装置１００の放射方向を示すステアリングベクトルａ（φ，θ）を乗算することにより（上記数１２及び数１３を用いる。）、励振素子Ａ０と平行な垂直面内の指向特性Ｅ^ｖ（θ，φ）と、励振素子Ａ０と直交する水平面内の指向特性Ｅ^Ｈ（θ，φ）とを計算する。
【００６８】
なお、この指向特性の計算において、詳細後述するように、ベクトル実効長ｌｅ_ｍに対して、実質的に１．１である補正係数γを乗算することによりベクトル実効長ｌｅ_ｍを補正することが好ましく、これにより、指向特性の計算精度を大幅に向上できる。
【００６９】
ところで、従来技術のアレーアンテナ装置１５０では、到来した無線信号の水平偏波成分を受信できなかったので、受信信号のうちの水平偏波の無線信号から生じた成分Ｅ^Ｖ×ｕ（ｔ）しか取得することができなかった。それに対して、本実施形態のアレーアンテナ装置１００では、数２０からわかるように、受信信号ｙ（ｔ）の中に、到来した無線信号の垂直偏波成分と水平偏波成分との両方が含まれているので、アレーアンテナ装置１００のアンテナ利得は、従来技術のアレーアンテナ装置１５０と比較して向上することが期待される。
【００７０】
図４は、本発明に係るアレーアンテナ装置と従来技術のアレーアンテナ装置とにおいてベクトル実効長を計算するときに考慮されている概念を示す表である。この表では特に、これまでのアレーアンテナに対する等価ウェイトベクトル表現における、ベクトル実効長の概念の拡張の経過をまとめている。最初に、本発明者らは、非特許文献４及び５（第１の従来例という。）において、アレーアンテナの素子上電流分布が一定でないことを見い出し、ベクトル実効長の導入を提案した。ベクトル実効長は、各非励振素子に装荷された可変リアクタンス素子のリアクタンス値にほぼ比例していることを示した。方向依存性は全て等しいので素子パターンとして分離して議論した。次に、本発明者らは、非特許文献６（第２の従来例と呼ぶ。）において、アレーアンテナに関してベクトル実効長はポート電流ｉ_ｍと電圧ｖ_ｍで表されることを示した。この段階でベクトル実効長は複素数に拡張され、位相情報を有するようになった。そして、本実施形態に係るアレーアンテナ装置１１０のための等価ウエイトベクトル表現では、第２の従来例の内容に加えてさらに、ベクトル実効長に対して、実空間におけるベクトルの特性と方向依存性とを導入した。
【００７１】
図１の適応制御型コントローラ２０は、以上の原理に基づいて、所定の評価関数を用いてアレーアンテナ装置１００を制御する。以下、いくつかの評価関数を用いたときに、適応制御型コントローラ２０がアレーアンテナ装置１００をそれぞれ制御する方法について説明する。
【００７２】
図１を参照してすでに説明された実施形態では、適応制御型コントローラ２０は、相手先の送信機から送信される無線信号に含まれる学習シーケンス信号をアレーアンテナ装置１００の励振素子Ａ０により受信したときの受信信号ｙ（ｔ）と、上記学習シーケンス信号と同一の信号パターンを有して学習シーケンス信号発生器２１で発生された学習シーケンス信号ｒ（ｔ）とに基づく所定の評価関数値を計算し、最急勾配法による適応制御処理を実行した。このとき、評価関数として、次式で定義される受信信号ｙ（ｔ）と学習シーケンス信号ｒ（ｔ）との相互相関係数を用いることができる（非特許文献７を参照）。
【００７３】
【数２２】

【００７４】
ここで、連続時間のパラメータｔは、離散化されたパラメータｎで表されている。ｙ（ｎ）は、所定時刻ｎから受信される所定のＰ個のシンボルの受信信号にてなるベクトルを表し、ｒ（ｎ）は、時刻ｎから受信される所定のＰ個のシンボルの学習シーケンス信号にてなるベクトルを表し、適応制御型コントローラ２０は、ベクトルｙ（ｎ）とｒ（ｎ）に基づいて数２２を用いて評価関数値Ｊ_１を計算する。適応制御型コントローラ２０は、可変リアクタンス素子のリアクタンス値を順次所定の差分幅だけ摂動させ、各リアクタンス値に対して上記評価関数値Ｊ_１を計算し、上記計算された評価関数値Ｊ_１に基づいて、例えば、最急勾配法を用いて、当該評価関数値Ｊ_１が最大となるように、各リアクタンス値を反復して計算することにより、当該アレーアンテナ装置１００の主ビームを所望波の方向に向けかつ干渉波の方向にヌルを向けるための各可変リアクタンス素子のリアクタンス値を計算して設定するように制御する。これにより、当該評価関数値が最大となるように、上記アレーアンテナ装置１００の主ビームを所望波の方向に向けかつ干渉波の方向にヌルを向けるための各可変リアクタンス素子のバイアス電圧値を探索し、探索された各バイアス電圧値を有する制御電圧信号を各可変リアクタンス素子に出力して設定する。
【００７５】
それに代わって、適応制御型コントローラ２０は、学習シーケンス信号ｒ（ｔ）を必要とせず、受信信号ｙ（ｔ）のみから計算可能な評価関数を用いることもできる。このようなリアクタンス値の推定はブラインド推定と呼ばれる。この場合は、図１の構成から学習シーケンス信号発生器２１を除去することができる。そのような評価関数として、例えば、非特許文献７に開示された数２３の式、非特許文献８に開示された数２４及び数２５の式を用いることができる。
【００７６】
【数２３】

【数２４】

【数２５】

【００７７】
数２３において、受信信号ｙ_ｐ（ｎ），（ｐ＝１，…，Ｐ）は、時刻ｎから受信されるＰ個のシンボルに対応し、数２３の評価関数Ｊ_２は、受信信号ｙ_ｐ（ｎ）のモーメントを最大化することに基づいた評価関数である。数２４の評価関数Ｊ_３は、受信信号ｙ_ｎの２次モーメントＥ｛｜ｙ_ｎ｜^２｝と４次モーメントＥ｛｜ｙ_ｎ｜^４｝に基づいた評価関数である。数２５において、受信信号ｙ_ｎはｍ相ＰＳＫ信号であり、数２５の評価関数Ｊ_４は、受信信号ｙ_ｎの高次モーメント比を表す汎関数である。
【００７８】
適応制御型コントローラ２０は、可変リアクタンス素子のリアクタンス値を順次所定の差分幅だけ摂動させ、各リアクタンス値に対して評価関数Ｊ_２乃至Ｊ_４のうちのいずれかの値を計算し、上記計算された評価関数値に基づいて、例えば、最急勾配法を用いて、当該評価関数値が最大となるように、各リアクタンス値を反復して計算することにより、当該アレーアンテナ装置１００の主ビームを所望波の方向に向けかつ干渉波の方向にヌルを向けるための各可変リアクタンス素子のリアクタンス値を計算して設定するように制御する。これにより、当該評価関数値が最大となるように、上記アレーアンテナ装置１００の主ビームを所望波の方向に向けかつ干渉波の方向にヌルを向けるための各可変リアクタンス素子のバイアス電圧値を探索し、探索された各バイアス電圧値を有する制御電圧信号を各可変リアクタンス素子に出力して設定する。
【００７９】
数２３乃至数２５の評価関数を用いるときは、学習シーケンス信号発生器２１が不要になるので、アレーアンテナ装置の制御装置の構成が簡単になる。また、適用制御型コントローラ２０が使用可能な評価関数は、上述の評価関数Ｊ_１乃至Ｊ_４のみに限定されるものではない。さらに、以上の実施形態では、最急勾配法を用いているが、本発明はこれに限らず、例えば、順次ランダム法、ランダム法、高次元二分法などの非線形計画法における反復的な数値解法を用いることができる。
【００８０】
なお、無線信号のうちの１方向に偏波した成分のみを送受信するためのアレーアンテナ（例えば図３６のアレーアンテナ装置１５０）の場合は、半波長ダイポール素子の代わりに、接地導体上の１／４波長モノポールのアンテナ素子を用いることができたが、鉛直方向に対して斜めに傾けたモノポールのアンテナ素子を接地導体上に設置すると、電波の鏡像において垂直偏波は同じ向きに写るが、水平偏波は逆向きに写り互いにキャンセルしあうので、接地導体と平行な水平偏波成分を含む無線信号を送受信するためには、接地導体上に設けられたモノポールの非励振素子を用いることは不適当である。従って、本実施形態の非励振素子としては、半波長ダイポールのアンテナ素子のみを用いることができる。しかしながら、励振素子には、接地導体上の１／４波長モノポールのアンテナ素子が使用されてもよい。もちろん、ダイポールの励振素子Ａ０も使用できる。
【００８１】
以上説明したように、本実施形態のアレーアンテナ装置の制御装置によれば、受信する無線信号の偏波に対するアンテナ利得を変化させ、かつ送信する無線信号の偏波を変化させることができるアレーアンテナ装置１００を制御し、特に受信時には、所望波方向の偏波面に対して当該アレーアンテナ装置１００で受信可能な偏波面を一致させ、干渉波に対しては、当該アレーアンテナ装置１００で受信可能な偏波方向を直交させるように、アレーアンテナ装置１００を制御することができる。また、説明されたアレーアンテナの等価ウエイトベクトル表現によれば、ベクトルの性質と方向依存性を考慮したアレーアンテナ装置１００の等価ウエイトベクトル表現を提供することができるので、この等価ウエイトベクトル表現を用いると、アレーアンテナ装置１００の指向特性をより正確に計算することができる。
【００８２】
＜第２の実施形態＞
図５は、本発明に係る第２の実施形態であるアレーアンテナ装置１１０の構成を示す斜視図であり、図６は、本発明に係る第２の実施形態の変形例であるアレーアンテナ装置１１１の構成を示す斜視図である。これらの実施形態は、右旋楕円偏波と左旋楕円偏波とを対称に実現するように偏波を変化させることができるアレーアンテナ装置である。
【００８３】
図５のアレーアンテナ装置１１０では、第１の実施形態のアレーアンテナ装置１００の構成に加えて、円周２００上で非励振素子Ａ１乃至Ａ６が位置する場所にそれぞれ、非励振素子Ａ１１乃至Ａ１６を非励振素子Ａ１乃至Ａ６の傾斜角ωとは逆の傾斜角（すなわち、−ω）で配置し、円周２００上に６対の十字型のダイポールアンテナを互いに所定の同一間隔だけ離れて形成する。当該傾斜角は第１の実施形態と同様に、傾斜角ωは０°＜ω＜９０°であり、好ましくは４５°である。非励振素子Ａ１１乃至Ａ１６はそれぞれ、その長手方向の中央部のポートに可変リアクタンス素子１２−１１乃至１２−１６が装荷されている。
【００８４】
図３６の無線環境においては、円偏波（又は楕円偏波）の無線信号は、反射面Ｓ１，Ｓ２などにおける反射によって偏波の旋回方向が反転する。所望波の有効受信や干渉波の除去のためには、右旋又は左旋の任意の楕円偏波を受信できることが望ましいと考えられる。後述のシミュレーション結果より、第１の実施形態のアレーアンテナ装置１００では、形成しやすい円偏波の旋回方向に差があることが分かるが、これは、アレーアンテナ装置１００では鉛直方向に対する非励振素子Ａ１乃至Ａ６の傾きが一方向のみであるため、すなわち、図２を参照すると、非励振素子Ａ１乃至Ａ６が、原点Ｏから各非励振素子Ａ１乃至Ａ６の長手方向の中央部とをそれぞれ結ぶ直線を回転軸としていずれも正の方向に角度ωで回転されているためと考えられる。同じリアクタンス値を設定した時、各非励振素子の傾斜角を、第１の実施形態とは逆の角度−ωにすれば、第１の実施形態のときとは逆向きの偏波が得られる。
【００８５】
一方、非特許文献９に記載されたように、可変リアクタンス素子が装荷されたダイポールのアンテナ素子は、適切なリアクタンス値を与えることにより電気的に除去可能である。すなわち、ｉ番目（１≦ｉ≦６）の非励振素子Ａｉに直交する方向のベクトル実効長ｌｅ_ｉは、ｉ番目の非励振素子に装荷される可変リアクタンス素子のリアクタンス値Ｘ_ｉを用いて、ｌｅ_ｉ＝ｌｅ_ｉ ^（０）（１−αＸ_ｉ）で表される。ここで、ｌｅ_ｉ ^（０）は、リアクタンス値が０［Ω］の状態、あるいは可変リアクタンス素子を装荷しない状態のベクトル実効長であり、物理的なアンテナ素子長の約６５％の値をとる。比例定数αはアンテナの構造、特にアンテナ素子自体の長さと太さによりほぼ決まる定数である。上記式より、ベクトル実効長は制御結果に実現される電流のアレー分布（等価ウェイトベクトル）に依存せず、制御パラメータであるリアクタンス値で決まる。また、非励振素子自体に装荷された可変リアクタンス素子のリアクタンス値Ｘ_ｉのみにより決まるので、他の非励振素子のリアクタンス値とは独立に制御できることが分かる。さらに、上記式の線形性より、リアクタンス値Ｘ_ｉを所定値に設定することによって、他の非励振素子の状態によらず、非励振素子Ａｉのベクトル実効長ｌｅ_ｉを常に０とすることができる。以上を要約すれば、所定のアンテナ素子上の電流の積分値が実質的に零になるようなリアクタンス値を、当該アンテナ素子に接続された可変リアクタンス素子に設定することによって、当該アンテナ素子のベクトル実効長を実質的に零にして当該アンテナ素子を電気的に除去することができる。
【００８６】
そこで、右旋楕円偏波と左旋楕円偏波の送受信のためにそれぞれ互いに逆の傾きで鉛直方向から傾けられたダイポールのアンテナ素子を予め配置する、図５及び図６のようなアレーアンテナ装置を提案する。図５のアレーアンテナ装置１１０では、右旋楕円偏波のためのアンテナ素子として非励振素子Ａ１乃至Ａ６を備え、左旋楕円偏波のためのアンテナ素子として非励振素子Ａ１１乃至Ａ１６を備えている。右旋楕円偏波の無線信号を送受信するときには、非特許文献９記載の方法に従って可変リアクタンス素子１２−１１乃至１２−１６に適切なリアクタンス値を設定することによって非励振素子Ａ１１乃至Ａ１６を電気的に除去し、第１の実施形態と同様に非励振素子Ａ１乃至Ａ６に装荷された可変リアクタンス素子１２−１乃至１２−６のリアクタンス値を制御し、右旋楕円偏波を形成することができる。同様に、左旋楕円偏波の無線信号を送受信するときには、非特許文献９記載の方法に従って可変リアクタンス素子１２−１乃至１２−６に適切なリアクタンス値を設定することによって非励振素子Ａ１乃至Ａ６を電気的に除去し、第１の実施形態と同様に非励振素子Ａ１１乃至Ａ１６に装荷された可変リアクタンス素子１２−１１乃至１２−１６のリアクタンス値を制御し、左旋楕円偏波を形成することができる。右旋楕円偏波のときと左旋楕円偏波のときとでは、アレーアンテナ装置１１０の水平面内指向特性が対称になる。
【００８７】
すなわち、図５のアレーアンテナ装置１１１では、右旋楕円偏波のためのアンテナ素子としての非励振素子Ａ１乃至Ａ６と、左旋楕円偏波のためのアンテナ素子としての非励振素子Ａ１１乃至Ａ１６とが、円周２００で所定の同一の間隔だけ離れて異偏波で交互に配置されているので、異偏波交互配置型ということができる。
【００８８】
また、図６のアレーアンテナ装置１１１においては、非励振素子Ａ２１乃至Ａ２６を非励振素子Ａ１乃至Ａ６の位置からそれぞれ３０度だけ円周２００上でずらして、隣接する非励振素子Ａ１とＡ２の間の位置、隣接する非励振素子Ａ２とＡ３の間の位置、隣接する非励振素子Ａ３とＡ４の間の位置、隣接する非励振素子Ａ４とＡ５の間の位置、隣接する非励振素子Ａ５とＡ６の間の位置、隣接する非励振素子Ａ６とＡ１の間の位置に配置しても、図５のアレーアンテナ装置１１０と同様の効果は得られる。すなわち、図６のアレーアンテナ装置１１１では、第１の実施形態のアレーアンテナ装置１００の構成に加えて、円周２００上で非励振素子Ａ１乃至Ａ６から３０°ずらした位置にそれぞれ、非励振素子Ａ２１乃至Ａ２６を非励振素子Ａ１乃至Ａ６とは逆の傾斜角−ωで配置する。非励振素子Ａ２１乃至Ａ２６にはそれぞれ、その長手方向の中央部のポートに可変リアクタンス素子１２−２１乃至１２−２６が装荷されている。アレーアンテナ装置１１１では、右旋楕円偏波のためのアンテナ素子として非励振素子Ａ１乃至Ａ６を備え、左旋楕円偏波のためのアンテナ素子として非励振素子Ａ２１乃至Ａ２６を備えている。アレーアンテナ装置１１１は、図５のアレーアンテナ装置１１０と同様に、非励振素子Ａ１乃至Ａ６の組と、非励振素子Ａ２１乃至Ａ２６の組とのうちの一方を、上述のごとく、非特許文献９記載の方法に従って電気的に除去し、残りの非励振素子の組で右旋楕円偏波又は左旋楕円偏波の無線信号を送受信することができる。
【００８９】
以上の実施形態においては、楕円偏波で送受信するアレーアンテナ装置１１０，１１１について説明しているが、傾斜角ωや可変リアクタンス素子のリアクタンス値を変化させることにより、円偏波で送受信するアレーアンテナ装置を構成できる。
【００９０】
以下、図１のアレーアンテナ装置の制御装置において、第１の実施形態のアレーアンテナ装置１００に代わって、アレーアンテナ装置１１０を備えたときの制御方法について説明する。
【００９１】
適応制御型コントローラ２０にはキーボードなどの入力装置２２が接続されている。復調器又は無線送信機７を用いた無線通信を開始する前に、ユーザは入力装置２２を用いて、非励振素子Ａ１乃至Ａ６の組又は非励振素子Ａ１１乃至Ａ１６の組のうち、電気的に除去したい非励振素子の組を選択して入力し、これに応答して、その指示内容を含む指示信号は入力装置２２から適応制御型コントローラ２０に入力される。適応制御型コントローラ２０は、選択された非励振素子上の電流の積分値が実質的に零になるようなリアクタンス値を、当該非励振素子に接続された可変リアクタンス素子に出力して設定することによって、当該非励振素子のベクトル実効長を実質的に零にして当該非励振素子を電気的に除去する。
【００９２】
また、送信時においても、入力装置２２からの指示信号に基づいて、ユーザにより選択された非励振素子の組（Ａ１乃至Ａ６、又はＡ１１乃至Ａ１６）上の電流の積分値が実質的に零になるようなリアクタンス値を、当該非励振素子に接続された可変リアクタンス素子に出力して設定することによって、当該非励振素子のベクトル実効長を実質的に零にして当該非励振素子を電気的に除去することもできる。
【００９３】
非励振素子Ａ１乃至Ａ６、又は非励振素子Ａ１１乃至Ａ１６のうちのいずれかを電気的に除去した後で、適応制御型コントローラ２０は、第１の実施形態と同様に所定の評価関数を用いて、アレーアンテナ装置１１０又は１１１の主ビームを所望波の方向に向けかつ干渉波の方向にヌルを向けるための、可変リアクタンス素子のうちで、電気的に除去されていない非励振素子に接続された可変リアクタンス素子に印加されるバイアス電圧値を探索して制御電圧信号を用いて設定する。
【００９４】
以上説明した実施形態では、電気的に除去すべき非励振素子をユーザが入力装置２２を用いて予め設定したが、それに代わって、適応制御型コントローラ２０が受信信号ｙ（ｔ）に基づいて自動的に設定してもよい。このとき、適応制御型コントローラ２０は、受信する無線信号が右旋偏波であると仮定して非励振素子Ａ１１乃至Ａ１６を電気的に除去した場合と、受信する無線信号が左旋偏波であると仮定して非励振素子Ａ１乃至Ａ６を電気的に除去した場合とについて、受信信号に対する所定の評価関数値（例えば、受信信号電力）を比較する。詳しくは、適応制御型コントローラ２０は、非励振素子Ａ１１乃至Ａ１６を電気的に除去して、非励振素子Ａ１乃至Ａ６に対応するリアクタンス値を適応的に制御した場合の評価関数値と、非励振素子Ａ１乃至Ａ６を電気的に除去して、非励振素子Ａ１１乃至Ａ１６に対応するリアクタンス値を適応的に制御した場合の評価関数値とを比較し、より大きいほうの評価関数値に対応するリアクタンス値、すなわち、当該評価関数値が大きくなるような偏波を受信できる非励振素子の組（すなわち、非励振素子Ａ１乃至Ａ６の組、又は非励振素子Ａ１１乃至Ａ１６の組）を残して他方の非励振素子の組を電気的に除去するようなリアクタンス値を、各非励振素子Ａ１乃至Ａ６及びＡ１１乃至Ａ１６に設定する。
【００９５】
なお、非励振素子Ａ１乃至Ａ６の組と非励振素子Ａ１１乃至Ａ１６の組とのうちの片方を電気的に除去しておく必要はないので、６×２個のリアクタンス値のパラメータを有効利用すれば、指向特性と偏波に関する可変な自由度はさらに向上する。この場合も、非励振素子Ａ１及びＡ１１，Ａ２及びＡ１２，…，Ａ６及びＡ１６のペア毎にリアクタンス値を入れ替えれば、偏波の向きがやはり逆転する。これは、垂直偏波は変わらないが、水平偏波の向きが変わるためである。
【００９６】
以上説明したように、本実施形態のアレーアンテナ装置によれば、右旋楕円偏波の無線信号と左辺楕円偏波の無線信号とを送受信することができるアレーアンテナ装置を提供することができる。
【００９７】
＜第３の実施形態＞
本実施形態では、可変リアクタンス素子をそれぞれ装荷した１つ又は複数の非励振素子を配列し、偏波を変化させることができるリニアアレーアンテナ装置について説明する。以下の実施形態もまた、図１のアレーアンテナ装置の制御装置において、アレーアンテナ装置１００と置き換えて使用することができる。
【００９８】
図７は、本発明に係る第３の実施形態であるアレーアンテナ装置１２０の構成を示す斜視図である。このアレーアンテナ装置１２０では、垂直状態の励振素子Ａ０に対して、平行でなく、かつ直交しない向きに非励振素子Ａ４１を配置し、その非励振素子に可変リアクタンス素子１２−４１（具体的には可変容量ダイオードダイオードなど）を装荷し、そのリアクタンス値を制御することにより、偏波を変化させている。具体的には、図７中のｘｙｚ座標を参照すると、半波長ダイポールの励振素子Ａ０は、ｚ軸上で、長手方向の中心を原点Ｏに合わせて配置され、半波長ダイポールの非励振素子Ａ４１は、ｙｚ平面と平行な平面内において、長手方向の中心がｘ軸上に位置するように、励振素子Ａ０からｘ軸の正の方向に所定距離だけ離れて並置される。非励振素子Ａ４１は、図３に示された第１の実施形態と同様に、ｘ軸を回転軸として、鉛直方向から所定の角度（例えば４５°）だけ回転されている。
【００９９】
アレーアンテナ装置１２０において、励振素子Ａ０で放射された、垂直偏波成分のみを含む無線信号は、非励振素子Ａ４１を励振し、次いで、非励振素子Ａ４１は垂直偏波成分と水平偏波成分を含む電波を放射することができる。本実施形態のアレーアンテナ装置１２０によれば、第１及び第２の実施形態のように複数本の非励振素子を備えなくても、励振素子Ａ０に対してｘ軸を回転軸とする傾斜角を有する１本以上の非励振素子が存在することで、アレーアンテナ装置で送受信する無線信号の偏波を変化させることができる。
【０１００】
なお、本実施形態では、非励振素子Ａ４１は、ｘ軸を回転軸として回転しているが、本発明はこれに限らず、ｚ軸とは異なる軸で回転させて、励振素子Ａ０と位置がずれかつ励振素子Ａ０に対して傾斜するように構成してもよい。このことは、以下に示す第３の実施形態の変形例でも同様である。
【０１０１】
図８は、本発明に係る第３の実施形態の第１の変形例であるアレーアンテナ装置１２１の構成を示す斜視図である。このアレーアンテナ装置１２１は、励振素子Ａ０と２個の非励振素子Ａ４１及びＡ４２とを並べたリニアアレーアンテナ装置である。
【０１０２】
図８のアレーアンテナ装置１２１において、図７の非励振素子Ａ４１の前（直線上でなくてもよい）に、さらに非励振素子Ａ４２を配置することにより、励振素子Ａ０と、２本の非励振素子Ａ４１及びＡ４２とをｘ軸上で並置している。具体的には、図８中のｘｙｚ座標を参照すると、半波長ダイポールの非励振素子Ａ４２は、ｙｚ平面と平行な平面内において、長手方向の中心がｘ軸上に位置するように、非励振素子Ａ４１からｘ軸の正の方向に所定距離だけ離れて配置される。非励振素子Ａ４２は、ｘ軸を回転軸として、鉛直方向に対して非励振素子Ａ４１とは異なる角度だけ回転されている。図８に示された実施例では、非励振素子Ａ４２は励振素子Ａ０に対して９０°回転されている。
【０１０３】
このように構成されたアレーアンテナ装置１２１によれば、利得向上と水平偏波成分の増加とが得ることができる。追加された非励振素子Ａ４２は、図８のように、励振素子Ａ０に対して直交していてもよい。非励振素子Ａ４２は励振素子Ａ０により直接に励振されないが、非励振素子Ａ４２を備えたことにより水平偏波成分が増大するのは、非励振素子Ａ４２を、可変リアクタンス素子１２−４１を装荷した非励振素子Ａ４１を介して励振させることが可能であることに起因する。また、追加する非励振素子Ａ４２には、必ずしも可変リアクタンス素子１２−４２を装荷する必要はない。可変リアクタンス素子１２−４２を装荷しない場合でも、八木宇田アレーアンテナの原理に従って、予め短く設計することにより導波器として動作させ、長く設計することにより反射器として動作させることが可能であり、制御の複雑さやコストを低減させることが期待できる。
【０１０４】
図９は、本発明に係る第３の実施形態の第２の変形例であるアレーアンテナ装置１２２の構成を示す斜視図である。このアレーアンテナ装置１２２は、３素子以上の複数の非励振素子を励振素子Ａ０の前後に配置するリニアアレーである。
【０１０５】
アレーアンテナ装置１２２において、具体的には、図９中のｘｙｚ座標を参照すると、図８のアレーアンテナ装置１２１の構成に加えて、ｘ軸の正の方向に非励振素子Ａ４３をさらに備え、ｘ軸の負の方向に非励振素子Ａ３９及びＡ３８をさらに備えている。ここで、励振素子Ａ０と、非励振素子Ａ４１，Ａ４２，Ａ３８，Ａ３９はｘ軸上で並置されている。半波長ダイポールの非励振素子Ａ４３は、ｙｚ平面と平行な平面内において、長手方向の中心がｘ軸上に位置するように、非励振素子Ａ４２からｘ軸の正の方向に所定距離だけ離れて配置される。非励振素子Ａ４３は、ｘ軸を回転軸として、鉛直方向に対して非励振素子Ａ４１及びＡ４２とは異なる角度（例えば１３５°）だけ回転されている。非励振素子Ａ４３の長手方向の中央部のポートには、可変リアクタンス素子１２−４３が装荷される。
【０１０６】
また、複数の非励振素子を励振素子Ａ０の前方（ｘ軸の正の方向）にのみ配置する必要はなく、図のように励振素子Ａ０の後方（ｘ軸の負の方向）にも配置し、それらを反射器として動作させることにより、アレーアンテナ装置の利得を向上できる。半波長ダイポールの非励振素子Ａ３９は、ｙｚ平面と平行な平面内において、長手方向の中心がｘ軸上に位置するように、励振素子Ａ０からｘ軸の負の方向に所定距離だけ離れて配置される。非励振素子Ａ３９は、ｘ軸を回転軸として、鉛直方向に対して非励振素子Ａ４１乃至Ａ４３とは異なる角度（例えば−４５°）だけ回転されている。非励振素子Ａ３９の長手方向の中央部のポートには、可変リアクタンス素子１２−３９が装荷される。同様に、半波長ダイポールの非励振素子Ａ３８は、ｙｚ平面と平行な平面内において、長手方向の中心がｘ軸上に位置するように、非励振素子Ａ３９からｘ軸の負の方向に所定距離だけ離れて配置される。非励振素子Ａ３８は、ｘ軸を回転軸として、鉛直方向に対して非励振素子Ａ３９とは異なる角度（例えば−９０°）だけ回転されている。非励振素子Ａ３８の長手方向の中央部のポートには、可変リアクタンス素子１２−３８が装荷される。
【０１０７】
アレーアンテナ装置１２２によれば、八木宇田アレーアンテナの原理に従って、偏波制御の自由度と利得とを向上させることが可能である。各アンテナ素子を必ずしも直線状に配置する必要はない。また、いくつかの非励振素子（図９の実施例では、非励振素子Ａ４２及びＡ３８）は励振素子Ａ０と直交した状態に配置することができる。また、複数のリアクタンス値を制御する処理を簡単化するために、すべての非励振素子に可変リアクタンス素子を装荷しなくてもよい。
【０１０８】
＜第４の実施形態＞
図１０は、本発明に係る第４の実施形態であるアレーアンテナ装置１３０の構成を示す斜視図である。このアレーアンテナ装置１３０は、励振素子Ａ０の周囲に、非励振素子が２重に配列され、偏波を変化させることができるアレーアンテナ装置である。この実施形態もまた、図１のアレーアンテナ装置の制御装置において、アレーアンテナ装置１００と置き換えて使用することができる。
【０１０９】
図１０に示されたｘｙｚ座標を参照すると、アレーアンテナ装置１３０は、第１の実施形態のアレーアンテナ装置１００の構成に加えて、原点Ｏを中心として円周２００よりも大きな半径を有するｘｙ平面内の円周２１０上に配置された、半波長ダイポールの非励振素子Ａ５１乃至Ａ５６をさらに備えたことを特徴とする。非励振素子Ａ５１乃至Ａ５６は、その長手方向を円周２１０の接線方向に合わせて配置され、非励振素子Ａ５１の長手方向の中心は、原点Ｏと非励振素子Ａ１の長手方向の中心との延長線上に位置し、非励振素子Ａ５２の長手方向の中心は、原点Ｏと非励振素子Ａ２の長手方向の中心との延長線上に位置し、以下、非励振素子Ａ５３乃至Ａ５６についても同様である。
【０１１０】
図１０のアレーアンテナ装置１３０の実施例では、非励振素子Ａ１乃至Ａ６とＡ５１乃至Ａ５６とを半径が異なる２つの円周上に配列したが、非励振素子は２重に限らず、３重、４重等に配列されてもよい。これにより、偏波制御の自由度と利得とを向上させることができる。１重の場合（すなわち第１の実施形態と同様の場合）は、励振素子Ａ０が垂直偏波であるので、水平偏波成分の励振が弱い。前述のように、第１の実施形態では、非励振素子Ａ１乃至Ａ６は励振素子Ａ０と直交してはならなかった。そこで、図１０のように外側の円周２１０上に、水平にダイポールの非励振素子Ａ５１乃至Ａ５６を配置することにより、水平偏波を増加し、例えば円偏波軸比（垂直成分と水平成分のレベル差）を改善できる。また、外側の円周２１０上の非励振素子Ａ５１乃至Ａ５６には可変リアクタンス素子を装荷しなくてもよい。これにより、制御の複雑化を回避できる。
【０１１１】
＜第５の実施形態＞
図１１は、本発明に係る第５の実施形態であるアレーアンテナ装置１４０の構成を示す斜視図である。この実施形態もまた、図１のアレーアンテナ装置の制御装置において、アレーアンテナ装置１００と置き換えて使用することができる。
【０１１２】
アレーアンテナ装置１４０は、第４の実施形態のアレーアンテナ装置１３０の構成に加えて、円周２００上で非励振素子Ａ１乃至Ａ６が位置する場所にそれぞれ、非励振素子Ａ１１乃至Ａ１６を非励振素子Ａ１乃至Ａ６とは逆の傾斜角（すなわち、−ω）で配置し、円周２００上に６個の十字型のダイポールを形成する。非励振素子Ａ１１乃至Ａ１６はそれぞれ、その長手方向の中央部のポートに可変リアクタンス素子１２−１１乃至１２−１６が装荷されている。従って、アレーアンテナ装置１４０は、第２の実施形態と同様に非励振素子Ａ１乃至Ａ６とＡ１１乃至Ａ１６とを備えたことにより右旋と左旋との対称な偏波を実現可能であり、第４の実施形態と同様に円周２００上に６対の十字ダイポール型アンテナを所定の同一間隔だけ離れて備えるとともに、円周２１０上にその長手方向が円周２１０の接線に平行である水平偏波用非励振素子Ａ５１乃至Ａ５６を所定の同一の間隔だけ離れて備えたことにより、２重に配列された非励振素子群を有し偏波を変化させることができるアレーアンテナ装置を構成できる。
【０１１３】
後述のシミュレーション結果からわかるように、図１のアレーアンテナ装置１００では右旋楕円偏波は実現しやすいが、左旋偏波は実現しにくい。そこで、対称な偏波特性を実現できるように、内側の非励振素子の配列の傾斜角が対称なペアを配置する。外側の円周２１０上に追加した水平なダイポールの非励振素子Ａ５１乃至Ａ５６は、非励振素子Ａ１乃至Ａ６の組に対しても、あるいは非励振素子Ａ１１乃至Ａ１６の組に対しても同様に動作するので、右旋偏波又は左旋偏波の無線信号に対して同様に水平偏波成分を増大させる効果をもたらす。
【０１１４】
【実施例】
以下のシミュレーションでは、第１の実施形態のアレーアンテナ装置１００を用いて、それの等価ウェイトベクトル表現を検証する。図２のような７素子のアレーアンテナ装置１００を解析する。各アンテナ素子の太さは０．０２λであり、ｘｙ平面内での各アンテナ素子の間隔はλ／４であり、非励振素子Ａ１乃至Ａ６の素子長はλ／２であり、励振素子Ａ０の素子長はλ／２^３／２であるとする。非励振素子Ａ１乃至Ａ６の傾斜角ωは全て等しく４５度とする。励振素子Ａ０と非励振素子Ａ１乃至Ａ６とのｚ軸方向の高さは等しい設定とした。図１２はアレーアンテナ装置１００の電気的構造パラメータを示す表である。図１２の表には、この構造のアレーアンテナ装置１００に対してモーメント法で計算して得られた電気的構造パラメータであるアドミタンス要素Ｙ_ｉｊと、励振素子Ａ０の給電ポートに同軸ケーブル５を接続しないときの励振素子Ａ０のベクトル実効長ｌｅ_０ ^（０）と、リアクタンス値が０Ωのときの非励振素子Ａｍのベクトル実効長ｌｅ_ｍ ^（０）と、数１４の比例定数α_ｍとが示されている。
【０１１５】
非励振素子Ａ１乃至Ａ６が傾斜角ωを持つため、従来の垂直な偏波面のみを有するアレーアンテナ装置１５０が有していた構造のｘｚ面に対する対称性はなくなったが、ｘ軸に対する１８０°の回転対称性が存在するため、アドミタンス要素Ｙ_ｉｊは数２６のような対称性を維持していることが分かった。
【０１１６】
【数２６】
Ｙ_１２＝Ｙ_１６
【数２７】
Ｙ_１３＝Ｙ_１５
【０１１７】
従って、独立なアドミタンス要素Ｙ_ｉｊは図１２の表に示す６個のみである。また、ベクトル実効長ｌｅ_ｍ ^（０）と比例定数α_ｍは、非特許文献５に従って、アンテナ素子上のアドミタンス分布から計算した。その結果、非特許文献４及び５で比例定数α_ｍはほぼ実数となっていたが、本実施形態のようにアンテナ素子を斜めに配置した場合には虚数部が無視できない程度に大きいことが分かったので、本実施形態で解析するアレーアンテナ装置１００では複素数として与える。
【０１１８】
図１３及び図１４は、図１２の表のパラメータを有するアレーアンテナ装置１００に対して、以下の表１に示されたケースＣ１及びＣ２の各リアクタンス値が設定されているときの当該アレーアンテナ装置１００の水平面内指向特性パターンをそれぞれ示すグラフである。
【０１１９】
【表１】

【０１２０】
ケース１のリアクタンス値は、アレーアンテナ装置１００の各可変リアクタンス素子１２−１乃至１２−６に設定されたときに、アレーアンテナ装置１００において所定の主ビーム方位角とビーム幅とを有するセクターパターンを形成するように選択されたものであり、一方、ケース２のリアクタンス値はランダムに選択されたものである。
【０１２１】
図１３及び図１４において、Ｅ^Ｖで示された曲線は電界の垂直偏波成分を示し、Ｅ^Ｈで示された曲線は電界の水平偏波成分を表す。方位角φによって垂直偏波と水平偏波の比率が変化していることが分かる。これは、前述されたように、励振素子Ａ０に対して反対の位置に配置される非励振素子同士で、励振される垂直偏波の向きが等しい時、水平偏波の向きは反対であるため、アレーアンテナ装置１００上で実現される偏波は方向によって異なると考察された内容と合致している。実線の曲線Ｅ^Ｖ（Ｍｏｍ）及びＥ^Ｈ（Ｍｏｍ）はモーメント法で計算した結果の電界を示し、粗い破線Ｅ^Ｖ（ｌｅ）及びＥ^Ｈ（ｌｅ）は等価ウェイトベクトルから計算した結果の電界を示す。両者はほぼ一致している。このことから、ベクトル実効長を方向依存性を有する実空間ベクトルとして扱うことにより、偏波を変化させることができるアレーアンテナ装置１００を、等価ウェイトベクトルを用いて表現できることが確認できた。
【０１２２】
しかしながら、特に垂直偏波の指向特性は非特許文献５に見られたほどの一致は見られない。この原因を調べるため、モーメント法で計算した素子上電流分布ｉ_ｍ（ｚ）と、等価ウェイトベクトルの計算で求めたポート電流ｉ_ｍ（０）とを図１５乃至図１８に示す。図１５は、アレーアンテナ装置１００にケースＣ１のリアクタンス値が設定されたときの、各アンテナ素子の素子上電流分布ｉ_ｍ（ｚ）とポート電流ｉ_ｍ（０）の振幅を示すグラフであり、図１６は、アレーアンテナ装置１００にケースＣ１のリアクタンス値が設定されたときの、各アンテナ素子の素子上電流分布ｉ_ｍ（ｚ）とポート電流ｉ_ｍ（０）の位相を示すグラフである。また、図１７は、アレーアンテナ装置１００にケースＣ２のリアクタンス値が設定されたときの、各アンテナ素子の素子上電流分布ｉ_ｍ（ｚ）とポート電流ｉ_ｍ（０）の振幅を示すグラフであり、図１８は、アレーアンテナ装置１００にケースＣ２のリアクタンス値が設定されたときの、各アンテナ素子の素子上電流分布ｉ_ｍ（ｚ）とポート電流ｉ_ｍ（０）の位相を示すグラフである。両計算法のポート電流ｉ_ｍ（０）は振幅及び位相とも良く一致していることが分かる。
【０１２３】
次にベクトル実効長の計算結果を調べる。図１９は、アレーアンテナ装置１００にケースＣ１のリアクタンス値が設定されたときの、各アンテナ素子のベクトル実効長を示すグラフであり、図２０は、アレーアンテナ装置１００にケースＣ２のリアクタンス値が設定されたときの、各アンテナ素子のベクトル実効長を示すグラフである。図１９及び図２０には、励振素子Ａ０のベクトル実効長ｌｅ_０で正規化したベクトル実効長ｌｅ_ｍの実数部と虚数部を示している。モーメント法による計算結果を中抜きの記号（中抜きの正方形□、及び４５°回転された正方形◇）で示し、数１４の等価ウエイトベクトルによる計算結果を中の詰まった記号（円●、及び中の詰まった正方形■）で示す。こちらも大きな違いはなく、数１４で素子上電流分布が精度良く表されていることが分かる。図１３及び図１４の指向特性において、垂直偏波に比べて水平偏波の指向特性の形は良く一致していることから、その差の原因は水平偏波に寄与しない励振素子Ａ０の放射波にあると推測できる。この放射波は無指向特性なので原因としてはその大きさが候補として残る。そこで、補正のために、励振素子Ａ０のベクトル実効長を相対的にγ倍した値を新たなベクトル実効長ｌｅ_ｍ ^（０）’とする。
【０１２４】
【数２８】
ｌｅ_ｍ ^（０）’＝γｌｅ_ｍ ^（０）
【０１２５】
補正係数γ＝１．１とした場合の結果を図１３及び図１４に、間隔の細かい破線Ｅ^Ｖ（ｌｅ’）及びＥ^Ｈ（ｌｅ’）で示す。垂直偏波、水平偏波ともにモーメント法の計算結果に近い結果が得られている。このことより、モーメント法の計算結果に合わせるためには、４５度の傾きを有する非励振素子Ａ１乃至Ａ６から放射される垂直偏波を小さく評価する必要があることが分かる。なお、数１９のように全てのアンテナ素子の素子パターンが等しいとしたが、図１２の表のように励振素子Ａ０と非励振素子Ａ１乃至Ａ６でベクトル実効長ｌｅ_ｍ ^（０）の相違が大きい場合には、素子上電流分布が異なっており素子パターンは等しくならないので、素子パターンの相違により、補正係数γ＝１．１の補正が必要となっている可能性がある。すなわち、最も好ましい実施形態では、補正係数γ＝１．１であるが、好ましくは、補正係数γは１．０を超えかつ１．２以下であり、より好ましくは、補正係数γは１．０５以上でかつ１．１５以下である。
【０１２６】
次に、水平方向の非励振素子Ａ０の方向（φ＝０°）と、非励振素子Ａ１及びＡ２の間の方向（φ＝３０°）とに注目して、アレーアンテナ装置１００において可変な偏波とビームパターンとを形成する能力を調べる。リアクタンス値の組み合わせで実現可能な電流のアレー配列（等価ウェイトベクトル）が明確でないため、解析的に最適解を見つけるのは困難なので、最急勾配法を用いる（非特許文献１０及び１１を参照）。ただし、最急勾配法で得られた収束状態は最適解とは限らない。リアクタンス値を変化させることができる範囲に制限はないものとする。また、反復におけるリアクタンス値の初期値は、非励振素子Ａ１（φ＝０）方向に注目するときは非励振素子Ａ１のリアクタンス値を−１００Ω、他の非励振素子Ａ２乃至Ａ６のリアクタンス値を０Ωとし、非励振素子Ａ１とＡ２の中間（φ＝３０）方向に注目するときには非励振素子Ａ１とＡ２のリアクタンス値を−１００Ω、他の非励振素子Ａ３乃至Ａ６のリアクタンス値を０Ωとする。なおベクトル実効長の計算では、数２８を用い補正係数γ＝１．１とした。最大化する評価関数として数２９乃至数３５のような量を用いる。
【０１２７】
【数２９】
｜Ｅ^Ｖ｜
【数３０】
｜Ｅ^Ｈ｜
【数３１】
｜Ｅ^Ｖ｜−｜Ｅ^Ｈ｜
【数３２】
｜Ｅ^Ｖ｜−｜Ｅ^Ｖ｜
【数３３】
｜Ｅ^Ｖ＋ｊＥ^Ｈ｜
【数３４】
｜Ｅ^Ｖ−ｊＥ^Ｈ｜
【数３５】
｜Ｅ^Ｖ｜＋｜Ｅ^Ｈ｜
【０１２８】
ここで、電界の垂直偏波成分Ｅ^Ｖと水平偏波成分Ｅ^Ｈとは、次式で定義される。
【０１２９】
【数３６】

【数３７】

【０１３０】
ここで、補正係数γ≒１．１であり、ｋは伝搬定数２π／λであり、ｄはアンテナ素子の間隔であって、本実施形態ではλ／４であり、さらに、方位角φ_ｍは次式で表される。
【数３８】
φ_ｍ＝２π（ｍ−１）／６
ｍ＝１，…，６
【０１３１】
それぞれ、数２９は垂直偏波、数３０は水平偏波、数３３は左旋円偏波、数３４は右旋円偏波が強くなる条件である。また、数３１は垂直偏波に対する水平偏波の交差偏波識別度、数３２は水平偏波に対する垂直偏波の交差偏波識別度が、また、数３５は放射電力が強くなる条件である。図２１は、所望波方向を０°とした場合と３０°とした場合とのそれぞれについて、適応制御型コントローラ２０が異なる評価関数を用いたときの各収束リアクタンス値を示す表である。図２２乃至図３５は、図２１の各所望波方向と各評価関数に対応する収束リアクタンス値がアレーアンテナ装置１００に設定されているときの水平面内指向特性パターンを示すグラフである。図２２乃至図３５において、図２１の表のリアクタンス値でモーメント法により計算した結果を、実線Ｅ^Ｖ（Ｍｏｍ）及びＥ^Ｈ（Ｍｏｍ）で表し、数２８の補正を行いベクトル実効長を考慮した等価ウェイトベクトル表現の結果を、破線Ｅ^Ｖ（ｌｅ’）及びＥ^Ｈ（ｌｅ’）で表す。また、垂直偏波成分Ｅ^Ｖ（Ｍｏｍ）及びＥ^Ｖ（ｌｅ’）を細線で、水平偏波成分Ｅ^Ｈ（Ｍｏｍ）及びＥ^Ｈ（ｌｅ’）を太線で示す。
【０１３２】
収束リアクタンス値の結果はモーメント法の結果に良く一致しており、拡張したベクトル実効長による等価ウェイトベクトル表現と、最急勾配法による最適化の手法の有効性が確認できる。全体的に垂直偏波に対し水平偏波のレベルが低い。これは大きな電流の流れる励振素子Ａ０から水平偏波成分が放射されないためである。このため、評価関数の収束状態の決定において垂直偏波が支配的な役割をしている。しかし、数３２の評価関数では、非励振素子が位置する方向と非励振素子間の方向に対して水平偏波を垂直偏波より強くすることは可能であることが分かる。逆に水平偏波を抑え、約１３ｄＢの交差偏波識別度を有する垂直偏波も実現できている。数３４の値を評価関数値とした場合、０度方向で１．９（５．６ｄＢ）、３０度方向で２．０（６．０ｄＢ）の円偏波軸比が得られている。軸比の良い円偏波は得られていない。また、右旋偏波を実現しようとすると、水平偏波成分が大きくなるが、左旋偏波を実現しようとすると水平偏波が小さくなる。また、数３２、数３４と数３５の収束結果がほぼ等しくなる。これらは水平偏波の励振位相が中央部の励振素子Ａ０の垂直偏波より進む傾向にあるためと考えられる。
【０１３３】
以上説明したように、実施形態に係るアレーアンテナの等価ウエイトベクトル表現によれば、ベクトルの性質と方向依存性を考慮したアレーアンテナ装置の等価ウエイトベクトル表現を提供することができる。従って、この等価ウエイトベクトル表現を用いると、アレーアンテナ装置の指向特性をより正確に計算することができる。
【０１３４】
以上説明したように、本発明に係る実施形態のアレーアンテナ装置によれば、ダイポールの非励振素子を傾けて配置することにより、励振素子が送受信する無線信号の偏波面に対して交差した偏波（又は直交した偏波）にアンテナ利得を有するアレーアンテナ装置を提供することができる。偏波を制御することにより所望波の送受信強度を増加し、干渉波抑圧の自由度を増加することができる。また、ダイポールのアンテナ素子のベクトル実効長に実空間ベクトルの特性と方向依存性とを考慮することにより、等価ウェイトベクトル表現が可能であることを示した。さらに、シミュレーションでは、最急勾配法を用いて、所望方向の偏波の可変能力を調べた。シミュレーション結果からは、素子方向及び素子間方向において、水平偏波を垂直偏波より強くすることが可能であること分かった。また、所望方向に軸比約２（６ｄＢ）の円偏波を実現できることが分かった。さらに、実現できる円偏波旋回方向の対称性を持たせるために、対称な傾きのダイポールのアンテナ素子を重ねて配置するアレーアンテナ装置も提案した。これにより、偏波が切り替え可能であり、また偏波の設定自由度が高いアレーアンテナ装置を実現することができる。
【０１３５】
【発明の効果】
以上詳述したように、本発明に係るアレーアンテナ装置によれば、電子制御導波器アレーアンテナ装置やリニアアレーアンテナ装置において、少なくとも１つの非励振素子を、励振素子に対して傾斜するように設けることにより、垂直偏波成分に加えて水平偏波成分の無線信号を送受信し、上記可変リアクタンス素子のリアクタンス値を変化させることにより、送受信する無線信号の垂直偏波成分及び水平偏波成分を制御する。これにより、当該アレーアンテナ装置の偏波を変化させることができる。従って、図３６に図示された無線環境などのマルチパス環境であっても、種々の偏波成分の無線信号を所定のアンテナ利得以上で送受信することができる。
【０１３６】
また、本発明に係るアレーアンテナ装置の制御方法又は装置によれば、上記アレーアンテナ装置の励振素子によって受信された受信信号に基づいて、非線形計画法における反復的な数値解法を用いて、上記受信信号を含む所定の評価関数の値が最大又は最小となるように、上記アレーアンテナの主ビームを所望波の方向に向けかつ干渉波の方向にヌルを向けるための可変リアクタンス素子のリアクタンス値を計算して設定する。従って、図３６に図示された無線環境などのマルチパス環境であっても、当該アレーアンテナ装置の放射パターン及びその偏波を実質的に最良の状態に設定して無線通信を行うことができる。
【図面の簡単な説明】
【図１】本発明に係る第１の実施形態であるアレーアンテナ装置の制御装置の構成を示すブロック図である。
【図２】図１のアレーアンテナ装置１００の詳細構成を示す斜視図である。
【図３】鉛直方向からの図２の非励振素子Ａ１の傾斜角ωと、ベクトル実効長の垂直成分及び水平成分とを示す図である。
【図４】図１のアレーアンテナ装置１００と従来のアレーアンテナ装置とにおいてベクトル実効長を計算するときに考慮されている概念を示す表である。
【図５】本発明に係る第２の実施形態であるアレーアンテナ装置１１０の構成を示す斜視図である。
【図６】本発明に係る第２の実施形態の変形例であるアレーアンテナ装置１１１の構成を示す斜視図である。
【図７】本発明に係る第３の実施形態であるアレーアンテナ装置１２０の構成を示す斜視図である。
【図８】本発明に係る第３の実施形態の第１の変形例であるアレーアンテナ装置１２１の構成を示す斜視図である。
【図９】本発明に係る第３の実施形態の第２の変形例であるアレーアンテナ装置１２２の構成を示す斜視図である。
【図１０】本発明に係る第４の実施形態であるアレーアンテナ装置１３０の構成を示す斜視図である。
【図１１】本発明に係る第５の実施形態であるアレーアンテナ装置１４０の構成を示す斜視図である。
【図１２】図１のアレーアンテナ装置１００の電気的構造パラメータを示す表である。
【図１３】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、アレーアンテナ装置１００にケースＣ１のリアクタンス値が設定されているときの水平面内指向特性パターンを示すグラフである。
【図１４】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、アレーアンテナ装置１００にケースＣ２のリアクタンス値が設定されているときの水平面内指向特性パターンを示すグラフである。
【図１５】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、アレーアンテナ装置１００にケースＣ１のリアクタンス値が設定されたときの、各アンテナ素子の素子上電流分布ｉ_ｍ（ｚ）とポート電流ｉ_ｍ（０）の振幅を示すグラフである。
【図１６】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、アレーアンテナ装置１００にケースＣ１のリアクタンス値が設定されたときの、各アンテナ素子の素子上電流分布ｉ_ｍ（ｚ）とポート電流ｉ_ｍ（０）の位相を示すグラフである。
【図１７】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、アレーアンテナ装置１００にケースＣ２のリアクタンス値が設定されたときの、各アンテナ素子の素子上電流分布ｉ_ｍ（ｚ）とポート電流ｉ_ｍ（０）の振幅を示すグラフである。
【図１８】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、アレーアンテナ装置１００にケースＣ２のリアクタンス値が設定されたときの、各アンテナ素子の素子上電流分布ｉ_ｍ（ｚ）とポート電流ｉ_ｍ（０）の位相を示すグラフである。
【図１９】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、アレーアンテナ装置１００にケースＣ１のリアクタンス値が設定されたときの、各アンテナ素子のベクトル実効長を示すグラフである。
【図２０】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、アレーアンテナ装置１００にケースＣ２のリアクタンス値が設定されたときの、各アンテナ素子のベクトル実効長を示すグラフである。
【図２１】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、適応制御型コントローラ２０が異なる評価関数を用いたときの各収束リアクタンス値を示す表である。
【図２２】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、所望波方向φ＝０°、評価関数｜Ｅ^Ｖ｜のときの収束リアクタンス値がアレーアンテナ装置１００に設定されているときの水平面内指向特性パターンを示すグラフである。
【図２３】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、所望波方向φ＝０°、評価関数｜Ｅ^Ｈ｜のときの収束リアクタンス値がアレーアンテナ装置１００に設定されているときの水平面内指向特性パターンを示すグラフである。
【図２４】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、所望波方向φ＝０°、評価関数｜Ｅ^Ｖ｜−｜Ｅ^Ｈ｜のときの収束リアクタンス値がアレーアンテナ装置１００に設定されているときの水平面内指向特性パターンを示すグラフである。
【図２５】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、所望波方向φ＝０°、評価関数｜Ｅ^Ｈ｜−｜Ｅ^Ｖ｜のときの収束リアクタンス値がアレーアンテナ装置１００に設定されているときの水平面内指向特性パターンを示すグラフである。
【図２６】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、所望波方向φ＝０°、評価関数｜Ｅ^Ｖ＋ｊＥ^Ｈ｜のときの収束リアクタンス値がアレーアンテナ装置１００に設定されているときの水平面内指向特性パターンを示すグラフである。
【図２７】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、所望波方向φ＝０°、評価関数｜Ｅ^Ｖ−ｊＥ^Ｈ｜のときの収束リアクタンス値がアレーアンテナ装置１００に設定されているときの水平面内指向特性パターンを示すグラフである。
【図２８】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、所望波方向φ＝０°、評価関数｜Ｅ^Ｖ｜＋｜Ｅ^Ｈ｜のときの収束リアクタンス値がアレーアンテナ装置１００に設定されているときの水平面内指向特性パターンを示すグラフである。
【図２９】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、所望波方向φ＝０°、評価関数｜Ｅ^Ｖ｜のときの収束リアクタンス値がアレーアンテナ装置１００に設定されているときの水平面内指向特性パターンを示すグラフである。
【図３０】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、所望波方向φ＝３０°、評価関数｜Ｅ^Ｈ｜のときの収束リアクタンス値がアレーアンテナ装置１００に設定されているときの水平面内指向特性パターンを示すグラフである。
【図３１】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、所望波方向φ＝３０°、評価関数｜Ｅ^Ｖ｜−｜Ｅ^Ｈ｜のときの収束リアクタンス値がアレーアンテナ装置１００に設定されているときの水平面内指向特性パターンを示すグラフである。
【図３２】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、所望波方向φ＝３０°、評価関数｜Ｅ^Ｈ｜−｜Ｅ^Ｖ｜のときの収束リアクタンス値がアレーアンテナ装置１００に設定されているときの水平面内指向特性パターンを示すグラフである。
【図３３】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、所望波方向φ＝３０°、評価関数｜Ｅ^Ｖ＋ｊＥ^Ｈ｜のときの収束リアクタンス値がアレーアンテナ装置１００に設定されているときの水平面内指向特性パターンを示すグラフである。
【図３４】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、所望波方向φ＝３０°、評価関数｜Ｅ^Ｖ−ｊＥ^Ｈ｜のときの収束リアクタンス値がアレーアンテナ装置１００に設定されているときの水平面内指向特性パターンを示すグラフである。
【図３５】図１のアレーアンテナ装置の制御装置のシミュレーション結果であって、所望波方向φ＝３０°、評価関数｜Ｅ^Ｖ｜＋｜Ｅ^Ｈ｜のときの収束リアクタンス値がアレーアンテナ装置１００に設定されているときの水平面内指向特性パターンを示すグラフである。
【図３６】従来技術に係るアレーアンテナ装置１５０に到来する無線信号の偏波成分を説明するための図である。
【符号の説明】
Ａ０…励振素子、
Ａ１乃至Ａ６，Ａ１１乃至Ａ１６，Ａ２１乃至Ａ２６，Ａ３８乃至Ａ４３，Ａ５１乃至Ａ５６…非励振素子、
１…低雑音増幅器（ＬＮＡ）、
２…ダウンコンバータ、
３…Ａ／Ｄ変換器、
４…復調器、
５…同軸ケーブル、
６…サーキュレータ、
７…無線送信機、
１１…接地導体、
１２−１乃至１２−６，１２−１１乃至１２−１６，１２−２１乃至１２−２６，１２−３８乃至１２−４３…可変リアクタンス素子、
２０…適応制御型コントローラ、
２１…学習シーケンス信号発生器、
２２…入力装置、
１００，１１０，１１１，１２０，１２１，１２２，１３０，１４０…アレーアンテナ装置、
２００，２１０…円周。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides an array antenna device such as an electronically steerable passive array radiator antenna device or a linear array antenna device which includes a plurality of antenna elements and can change directional characteristics, such as an electronically steerable passive array radiator antenna device. Method and apparatus.
[0002]
[Prior art]
Conventional electronically controlled waveguide array antenna devices have been proposed in, for example, Patent Document 1 and Non-Patent Document 1. The array antenna device is provided with an excitation element to which a radio signal is supplied, at least one non-excitation element to which a radio signal is not supplied, provided at a predetermined distance from the excitation element, and connected to the non-excitation element. And a variable reactance element, and by changing a reactance value of the variable reactance element, a directional characteristic of the array antenna can be changed.
[0003]
This array antenna device is an antenna which is constituted by one feed system and can obtain variable directional characteristics by using an inexpensive variable capacitance diode as a variable reactance element. For this reason, it has features such as small size, light weight, low power consumption, and low cost, so that it is expected to be a leader in the spread of adaptive antennas. In the adaptive control of the array antenna device, a signal of a received signal is controlled by directing a beam in a direction where a communication partner is located and controlling a directional characteristic of the array antenna device so as to direct null in a direction of arrival of an interference wave. The interference to noise power ratio (SINR) value can be improved.
[0004]
Non-Patent Documents 2 to 8 disclose the operation analysis, formulation, and control method of this array antenna device. Non-Patent Documents 9 to 11 disclose a method of controlling a current distribution on an antenna element in the array antenna apparatus to change a vector effective length of the antenna element.
[0005]
[Patent Document 1]
JP 2001-24431 A.
[Non-patent document 1]
Takashi Ohira et al., "Electronic control of antenna directional characteristics: Adaptive array from the viewpoint of high-frequency hardware design", IEICE Journal, IEICE, Vol. 83, no. 12, pp. 920-926, December 2000.
[Non-patent document 2]
Takahira Ohira et al., "Equivalent Weight Vector and Array Factor Expression of ESPAR Antenna", IEICE Technical Report, IEICE Technical Report, AP2000-44, SAT2000-41, MW2000-44, pp. 7-12, July 2000.
[Non-Patent Document 3]
Takashi Ohira et al., "Basic Formulation on Equivalent Weight Vector of ESPAR Antenna and Its Gradient," IEICE Technical Report, IEICE Technical Report, AP2001-16, SAT2001-3, pp. 15-20, May 2001.
[Non-patent document 4]
Kyoichi Iigusa et al., "High-precision Equivalent Weight Vector Based on Current Distribution on Element of ESPAR Antenna", IEICE Technical Report, IEICE Technical Report, AP2002-44, pp. 25-30, July 2002.
[Non-Patent Document 5]
Kyoichi Iigusa et al., "Consideration of vector effective length by admittance distribution on linear antenna array element", IEICE Technical Report, IEICE Technical Report, AP2002-109, pp. 45-52, October 2002.
[Non-Patent Document 6]
Kyoichi Iigusa, et al., "A Simple Method for Calculating the Current Distribution on Elements of a Linear Array Antenna from Port Current and Voltage", IEICE Technical Report, IEICE Technical Report, AP2002-117, pg. 31-38, December 2002.
[Non-Patent Document 7]
Hoshitoshi et al., "Experiment on Adaptive Control of ESPAR Antenna by MCCC and MMC Standards", IEICE General Conference, published by IEICE, B-1-117, 2002.
[Non-Patent Document 8]
Kenichi Takizawa et al., "Espa Antenna Adaptive Beamforming Norm Using SNR Blind Estimation", IEICE Technical Report, IEICE Technical Report, A-P2002-114, December 2002.
[Non-Patent Document 9]
Kyoichi Iigusa et al., "Reconfigurable Array Antenna for Making Elements Transparent by Reactance Control," IEICE Technical Report, IEICE Technical Report, AP2002-122, pp. 139-143. 19-24, January 2003.
[Non-Patent Document 10]
J. Cheng, et al. , "Adaptive Beamforming of ESPAR antenna based on graded algorithm", IEICE Transaction on Communication, E84-B, 7, July 2001.
[Non-Patent Document 11]
Kyoichi Iigusa, et al., "Study on beam null formation of ESPAR antenna by steepest gradient method", IEICE technical report, IEICE published by AP2002-27, pp. 33-38, May 2002.
[0006]
[Problems to be solved by the invention]
FIG. 36 is a diagram for explaining a polarization component of a radio signal arriving at the electronically controlled waveguide array antenna device 150 according to the related art disclosed in Patent Document 1 or the like. In the wireless environment in FIG. 36, the transmitting antenna device 160 transmits a linearly polarized wireless signal. In indoor wireless communication and the like, a large number of multipath waves exist, and the polarization of the multipath wave changes depending on the angle of incidence on the surface of the scatterer such as the reflection surfaces S1 and S2. The wave or the interference wave has a polarization component orthogonal to the transmitted wireless signal. However, the conventional electronically controlled waveguide array antenna device 150 has a problem that it can only receive a linearly polarized radio signal in a predetermined direction. In addition, this causes a problem that a radio signal to be received cannot be received with an optimum radiation pattern or polarization.
[0007]
An object of the present invention is to solve the above problems and to provide an array antenna apparatus capable of changing the polarization of a radio signal to be transmitted and received, and a control method and apparatus therefor.
[0008]
[Means for Solving the Problems]
An array antenna device according to a first aspect of the present invention provides an excitation element for transmitting and receiving a radio signal, at least one non-excitation element provided at a predetermined distance from the excitation element, and at least one non-excitation element And at least one variable reactance element connected to each of the variable reactance elements, and by changing a reactance value of each of the variable reactance elements, the at least one non-excitation element is operated as a director or a reflector, respectively, so that a directivity characteristic is obtained. In an array antenna device that changes
The at least one non-excitation element is formed of a dipole antenna and is provided so as to be inclined with respect to the excitation element, so that a radio signal of a horizontal polarization component in addition to a vertical polarization component parallel to the excitation element is provided. Is transmitted and received.
[0009]
In the above-mentioned array antenna apparatus, a vertical polarization component and a horizontal polarization component of a radio signal to be transmitted and received are controlled by changing a reactance value of the variable reactance element.
[0010]
Further, in the array antenna apparatus, a first non-excitation element inclined at a predetermined positive angle with respect to the excitation element, and a predetermined negative angle relative to the excitation element with a direction opposite to the angle. At least one set of a non-exciting element and a second non-exciting element that is inclined with respect to the reactance value of the variable reactance element connected to the first non-exciting element, and connected to the second non-exciting element. By changing the reactance value of the variable reactance element to be operated, at least one of the first parasitic element and the second parasitic element is operated.
[0011]
Further, in the array antenna apparatus, a reactance value such that an integral value of a current on one of the first and second parasitic elements becomes substantially zero is provided to the parasitic element. By setting the connected variable reactance element to make the vector effective length of the antenna element substantially zero and electrically removing the antenna element, only the other parasitic element is selectively operated. It is characterized by the following.
[0012]
Still further, in the above array antenna device, the first parasitic element and the second parasitic element in each set of the parasitic elements are provided at substantially the same position. Alternatively, in the array antenna apparatus, the first parasitic element and the second parasitic element in each set of the parasitic elements are provided at a predetermined distance from each other.
[0013]
Further, the array antenna apparatus is characterized in that at least one third non-excitation element is provided so as to be orthogonal to the excitation element.
[0014]
Further, in the array antenna device, instead of the plurality of non-excitation elements provided at a predetermined distance from the excitation element, a plurality of the excitation elements and the plurality of non-excitation elements are arranged so as to be arranged in a straight line. Characterized in that the non-excitation element is provided.
[0015]
A method for controlling an array antenna device according to a second aspect of the present invention is the method for controlling an array antenna device according to the present invention, wherein the iterative numerical solution in a nonlinear programming method is used based on a reception signal received by the excitation element. The reactance of the variable reactance element for directing the main beam of the array antenna in the direction of the desired wave and nulling in the direction of the interference wave so that the value of the predetermined evaluation function including the received signal is maximum or minimum. It is characterized by calculating and setting a value.
[0016]
A control device for an array antenna device according to a third invention is the control device for the array antenna device, wherein the control device uses an iterative numerical solution in a nonlinear programming method based on a reception signal received by the excitation element. The reactance of the variable reactance element for directing the main beam of the array antenna in the direction of the desired wave and nulling in the direction of the interference wave so that the value of the predetermined evaluation function including the received signal is maximum or minimum. A control means for calculating and setting a value is provided.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
In the wireless environment of FIG. 36 described in the section of the related art, for example, the number of received signals can be increased by receiving orthogonal polarization components of a desired wave. Also, interference wave removal can be realized by making the polarization of the electronically controlled waveguide array antenna device orthogonal to the polarization direction of the interference wave in that direction without forming a null in the direction of arrival of the interference wave. it can. Furthermore, since the interference wave arrives from several directions, it is considered that the degree of freedom of the polarization may be used so as to reduce the total of the reception signals of the interference wave without reducing each interference wave. The electronically controlled waveguide array antenna device proposed so far has been a vertically polarized antenna using a monopole or a dipole. In the present embodiment, an electronically controlled director array antenna device having a predetermined antenna gain with respect to horizontal polarization is proposed, and it is shown that polarization in a desired direction can be controlled by a reactance value of a variable reactance element. In this case, the steepest gradient method is used because the optimum state of polarization cannot be obtained analytically. For this purpose, a method for obtaining an equivalent weight vector expression for the proposed electronically controlled waveguide array antenna device will be described below.
[0019]
<First embodiment>
FIG. 1 is a block diagram showing a configuration of a control device of an array antenna device including an array antenna device 100 which is an electronically controlled waveguide array antenna device according to a first embodiment of the present invention. As shown in FIG. 1, the control device of the array antenna device according to this embodiment includes one excitation element A0 and six non-excitation elements A1 to A6 loaded with variable reactance elements 12-1 to 12-6, respectively. And an adaptive control type controller 20. The array antenna apparatus 100 is an antenna capable of communicating not only vertically polarized components but also horizontally polarized components. It has a gain and can change the polarization of the array antenna device 100.
[0020]
In the following description, the xyz coordinates in FIG. 1 are used, the longitudinal direction of the excitation element A0 is the z-axis, and the plane of the ground conductor 11 is orthogonal to the z-axis and the xy plane. Here, the component of the vertical polarization radiated from the excitation element A0 has a plane of polarization parallel to the z-axis, and the polarization orthogonal to the plane of polarization is called horizontal polarization.
[0021]
FIG. 2 is a perspective view showing a detailed configuration of the array antenna device 100 of FIG. As shown in FIG. 2, the array antenna device 100 includes seven half-wavelength dipole antenna elements, that is, an excitation element A0 and a non-excitation element provided on a circumference 200 having a predetermined radius centered on the excitation element A0. It is composed of elements A1 to A6. Specifically, with reference to the xyz coordinates in FIG. 2, the excitation element A0 is arranged with the center in the longitudinal direction on the z-axis at the origin O, and the non-excitation elements A1 to A6 have respective longitudinal elements. The centers of the directions are arranged at equal intervals on the circumference 200 in the xy plane centered on the origin O. The radius of the circumference 200 is configured to be, for example, about λ / 4 with respect to the wavelength λ of the desired wave. Here, in the conventional array antenna device 150, the excitation element A0 and the non-excitation elements A1 to A6 are arranged in parallel with each other, but in the array antenna device 100 of the present embodiment, the orientation of each of the non-excitation elements A1 to A6. Are twisted with respect to the longitudinal direction (vertical direction) of the excitation element A0. Specifically, as shown in FIG. 3, the parasitic element A1 has an inclination angle ω from a vertical direction with a straight line having a radius passing through the origin O and a center point OA1 in the longitudinal direction of the parasitic element A1 as an axis. Just being rotated. The inclination angle ω is 0 ° <ω <90 °, and is preferably 45 °. Each of the parasitic elements A2 to A6 is also rotated from a vertical direction by, for example, the same inclination angle ω about a straight line having a radius passing through the origin O and a center point in the longitudinal direction of each parasitic element. However, even if the inclination direction of the parasitic elements A1 to A6 is not a rotation about an axis passing through the origin and the center in the longitudinal direction of each parasitic element, a variable polarization characteristic can be obtained. Rotation about another axis such as a tangential axis may be used. In this embodiment, the number of non-excited elements is 6, but if it is one or more, the polarization is variable.
[0022]
A feed point (referred to as a port of the excitation element A0) located at the center in the longitudinal direction of the excitation element A0 is connected to a low noise amplifier (LNA) 1 via a coaxial cable 5 and a circulator 6. Further, the parasitic elements A1 to A6 are connected to the variable reactance elements 12-1 to 12-6 at the centers in the longitudinal direction, respectively. Specifically, for example, as shown in FIG. 1, the parasitic element A3 is a dipole antenna composed of a pair of antenna elements, and a variable reactance element 12 -3 is connected. Similarly, the other variable reactance elements 12-1, 12-2, 12-4 to 12-6 are connected to the non-excitation elements A1, A2, A4 to A6. These variable reactance elements 12-1 to 12-6 change their reactance values in response to a control voltage signal from the adaptive control type controller 20. In FIG. 2 and FIGS. 5 to 11, for simplification of the notation, the central parts on the parasitic elements to which the variable reactance elements 12-1 to 12-6 are connected are denoted by reference numerals 12-1 to 12-6. Indicates that the variable reactance elements 12-1 to 12-6 are provided.
[0023]
The operation of the variable reactance elements 12-1 to 12-6 will be described. For example, when the longitudinal lengths of the excitation element A0 and the non-excitation elements A1 to A6 are substantially the same, for example, the variable reactance element 12-1 Has an inductance property (L property), the variable reactance element 12-1 becomes an extension coil, and the electrical length of the non-exciting elements A1 to A6 becomes longer than that of the exciting element A0, thus acting as a reflector. On the other hand, for example, when the variable reactance element 12-1 has a capacitance property (C property), the variable reactance element 12-1 becomes a shortening capacitor, and the electrical length of the non-excitation element A1 becomes shorter than that of the excitation element A0. , Work as a director. The same applies to the non-exciting elements A2 to A6 connected to the other variable reactance elements 12-2 to 12-6.
[0024]
In the present embodiment, the array antenna device 100 can transmit and receive a radio signal including a horizontally polarized component by disposing the non-exciting elements A1 to A6 obliquely to the vertical direction. In the case of transmission, the excitation element A0 directly transmits the vertically polarized wave and simultaneously excites the non-excitation elements A1 to A6 installed at an angle. The excited non-exciting elements A1 to A6 transmit the vertical polarization component of the radio signal and simultaneously transmit the horizontal polarization component. As described above, the horizontal polarization component of the radio signal is radiated only from the non-exciting elements A1 to A6. Therefore, in the array antenna apparatus 100 of FIG. 1, the bias voltage value applied to the variable reactance elements 12-1 to 12-6 connected to the respective non-exciting elements A1 to A6 is changed, and the reactance corresponding to the junction capacitance value is changed. By changing the value, it is possible to change the planar directivity characteristics of the array antenna device 100 and the polarization of a radio signal transmitted and received by the array antenna device 100.
[0025]
Assuming that the inclination angles ω of the non-exciting elements A1 to A6 from the vertical direction are all equal, the non-exciting elements disposed at positions opposite to each other with respect to the exciting element A0 have the same direction of the vertically polarized wave excited. At times, the directions of horizontal polarization are opposite. Therefore, the polarization realized on the array antenna device 100 differs depending on the direction. This will be described in detail later.
[0026]
In FIG. 1, an adaptive control type controller 20 is constituted by a digital computer such as a computer. At the time of reception, the adaptive control type controller 20 transmits the learning sequence signal included in the radio signal transmitted from the counterpart transmitter to the excitation element A0 of the array antenna apparatus 100 before starting the radio communication by the demodulator 4. Based on the received signal y (t) when received by the learning sequence signal r (t) generated by the learning sequence signal generator 21 having the same signal pattern as the learning sequence signal. An adaptive control process based on the steepest gradient method is executed using the evaluation function. In this adaptive control process, a bias voltage applied to each of the variable reactance elements 12-1 to 12-6 for directing the main beam of the array antenna apparatus 100 in the direction of a desired wave and in nulling in the direction of an interference wave. The value is searched and set using the control voltage signal.
[0027]
The transmitting station transmitting the radio signal received by the array antenna 100 is a digital data of a predetermined symbol rate including a learning sequence signal having the same signal pattern as the predetermined learning sequence signal generated by the learning sequence signal generator 21. According to the signal, the carrier signal of the radio frequency is modulated using a digital modulation method such as BPSK or QPSK, and the modulated signal is power-amplified and transmitted to the array antenna device 100 of the receiving station. In the present embodiment, before performing data communication, a wireless signal including a learning sequence signal is transmitted from the transmitting station to the receiving station, and the adaptive control type controller 20 executes adaptive control processing at the receiving station.
[0028]
The array antenna device 100 receives a radio signal from a transmitting station, and the received signal is input to a low noise amplifier (LNA) 1 via a coaxial cable 5 and a circulator 6 and amplified, and then downconverted ( The D / C 2 converts the amplified signal into a signal of a predetermined intermediate frequency (IF signal). Further, the A / D converter 3 A / D converts the low-frequency converted analog signal into a digital signal, and outputs the digital signal to the adaptive control type controller 20 and the demodulator 4. Next, the adaptive control type controller 20 sequentially perturbs the reactance value of the variable reactance element by a predetermined difference width based on the received signal y (t) and the learning sequence signal r (t), and obtains each reactance value. Calculate a predetermined evaluation function value for, and, based on the calculated evaluation function value, for example, using the steepest gradient method, repeat each reactance value so that the evaluation function value is maximized. Thus, the control is performed such that the reactance value of each variable reactance element for directing the main beam of the array antenna apparatus 100 in the direction of the desired wave and nulling in the direction of the interference wave is calculated and set. Thereby, the bias voltage value of each variable reactance element for directing the main beam of the array antenna apparatus 100 in the direction of the desired wave and nulling in the direction of the interference wave is searched so that the evaluation function value becomes the maximum. Then, the control voltage signal having the searched bias voltage value is output to each variable reactance element and set.
[0029]
In the above embodiment, the steepest gradient method is used, but the present invention is not limited to this, and another adaptive control method may be used. Further, a specific example of the evaluation function will be described later in detail.
[0030]
The wireless transmitter 7 modulates a wireless carrier by a predetermined modulation method based on an input transmission baseband signal, and modulates a wireless signal as a modulated wireless carrier via the circulator 6 and the coaxial cable 5 into an array antenna device. 100 to the excitation element A0, whereby a radio signal is radiated from the array antenna device 100. At the time of transmission, the adaptive control type controller 20 sets, for example, the reactance values of the respective variable reactance elements 12-1 to 12-6 set at the time of reception to the respective variable reactance elements 12-1 to 12-6. .
[0031]
As described above, according to the present embodiment, in the array antenna device 100, the bias voltage applied to the variable reactance elements 12-1 to 12-6 connected to the non-exciting elements A1 to A6 is changed. By changing the reactance value, which is the junction capacitance value, it is possible to change the planar directivity characteristics of the array antenna device 100 and the polarization of a radio signal transmitted and received by the array antenna device 100.
[0032]
Next, in order to explain the control method of the array antenna device of the present embodiment, first, a signal model of a signal received by the array antenna device 100 is formulated.
[0033]
At a time t represented by a continuous time, the transmitted radio signal u (t) has an azimuth φ (centered on the origin O and an xy plane from the center of the parasitic element A1) as shown in FIG. ) And an elevation angle (an angle from the vertical direction which is the z-axis direction) θ. s_m(T) (m = 0, 1,..., 6) indicates a signal arriving at the m-th element of the array antenna apparatus 100, and s (t) indicates the m-th component s_mAssuming that the column vector has (t), the column vector s (t) can be expressed as follows.
[0034]
(Equation 1)
s (t) = a (θ, φ)^Tu (t)
[0035]
Here, the superscript T represents a transposed matrix. The steering vector a (θ, φ) is represented by the following equation as a function of the elevation angle θ and the azimuth angle φ of the radio signal arriving at the array antenna device 100.
[0036]
(Equation 2)

[0037]
Here, β is a propagation constant 2π / λ, d is an interval between antenna elements, and in the present embodiment, λ / 4, and
(Equation 3)
φ_m= 2π (m-1) / 6
m = 1, ..., 6
It is.
[0038]
According to this signal model, the received signal y (t) received by the array antenna device 100 can be expressed as follows.
[0039]
(Equation 4)
y (t) = i^Ts (t) = i^Ta (θ, φ) u (t)
[0040]
Here, the vector i = [i₀, I₁, ..., i₆]^TDenotes a high-frequency current vector of the array antenna apparatus 100, which has the same role as a weight vector in a conventional array antenna capable of observing signals on each element, and is referred to as an "equivalent weight vector" in the present embodiment. The equivalent weight vector i is formulated as follows.
[0041]
(Equation 5)

Or
(Equation 6)
i = (Y^-1+ X)^-1[V_s, 0, ..., 0]^T
[0042]
Where v_sIs a constant representing the feed voltage, and Zs is a constant representing the output impedance of the array antenna device 100. The diagonal matrix X is called a reactance matrix, and is a matrix having components of the output impedance Zs of the array antenna device 100 and the reactance value Xm (m = 1,..., 6) of the variable reactance element multiplied by the imaginary unit j. It is. Further, in Equation 5, Y = [Y_kl]_{(6 + 1) × (6 + 1)}Is called an admittance matrix, and its element Y_klRepresents a mutual admittance element between the element Ak and the element Al (0 ≦ k, l ≦ 6) of the array antenna apparatus 100. Admittance element Y_klAccording to the well-known reciprocity theorem, the value of_kl= Y_lkHolds. Admittance element Y_klIs constant depending on the physical structure of the antenna, for example, the radius, the spacing between the spaces, and the length of the element. Further, the rotational symmetry of the array antenna device 100 satisfies the following relationship.
[0043]
(Equation 7)
Y₁₁= Y₂₂= Y₃₃= Y₄₄= Y₅₅= Y₆₆
(Equation 8)
Y₀₁= Y₀₂= Y₀₃= Y₀₄= Y₀₅= Y₀₆
(Equation 9)
Y₁₂= Y₂₃= Y₃₄= Y₄₅= Y₅₆= Y₆₁
(Equation 10)
Y_Thirteen= Y₂₄= Y₃₅= Y₄₆= Y₅₁= Y₆₂
(Equation 11)
Y₁₄= Y₂₅= Y₃₆
[0044]
Therefore, the admittance matrix Y has six components Y of the admittance element.₀₀, Y₁₀, Y₁₁, Y₂₁, Y₃₁And Y₄₁It is understood that it is determined only by. Hereinafter, for the sake of simplicity, the received signal output from the array antenna device 100 and the received signal output from the A / D converter 3 are identified as y (t).
[0045]
Next, the concept of the vector effective length related to each antenna element of the array antenna device 100 will be introduced, and the fact that the vector effective length has vector properties and direction dependency will be described.
[0046]
The array antenna device 100 of the present embodiment and the array antenna device as disclosed in Patent Document 1, unlike a normal array antenna, cannot directly control the current excited on each antenna element and can be realized by a reactance value. It is difficult to analytically determine a reactance value for realizing a desired directional characteristic or polarization because the array arrangement of the currents (equivalent weight vector) is not clear. Therefore, a convergent solution by iteration using the steepest gradient method is used. For this purpose, the equivalent weight vector expression (see Non-Patent Documents 2 and 3) is convenient, and therefore, the array antenna device 100 of the present embodiment is formulated.
[0047]
Ports of the antenna elements Am (m = 0, 1,..., 6) (in the present embodiment, located at the central portion in the longitudinal direction of each antenna element and refer to ports at feed points of a pair of antenna elements). Flowing current i_mIs an important value for signal processing and reactance control because it is equal to the current flowing through the circuit elements such as the feed line and the variable reactance element 12-m. Also, this current i_mCan be calculated by circuit theory. This current i_mIs defined as an equivalent weight vector i, and an array factor (that is, the directivity characteristic of the array antenna apparatus 100) E (θ, φ) is calculated by the product of the equivalent weight vector i and the steering vector a (θ, φ). (See Non-Patent Documents 2 and 3). However, the radio wave is transmitted at the port current i_mIt is radiated by the entire current flowing not only from the antenna element but also over the antenna element, and similarly at the time of reception, the arriving radio wave generates a current flowing through the entire antenna element. The current distribution (magnitude, phase and shape) on the antenna element Am is the vector effective length le_mCan be expressed by Note that the vector effective length le of the antenna element having no variable reactance element is loaded._m ⁽⁰⁾Can be represented by γ × Lm which is almost proportional to the physical length Lm of each antenna element Am. Here, the proportionality constant γ is about 0.65. The proportionality constant γ depends exactly on the antenna structure, but does not change significantly. Here, a new current i ′ flowing through each antenna element Am_mIs represented by Expression 12.
[0048]
(Equation 12)
i '_m= Le_mi_m
[0049]
i '_mIf a new equivalent weight vector having a component as is represented by i ′, the array factor E (θ, φ) is calculated by Expression 13.
[0050]
(Equation 13)
E (θ, φ) = a^T(Θ, φ) i ′
[0051]
In Non-Patent Documents 4 and 5, the vector effective length le_mIs not constant and varies for each antenna element. In Non-Patent Document 6, the vector effective length le_mIs the port current i_mAnd voltage v_mIt has been shown that the expression can be expressed as shown in Expression 14.
[0052]
[Equation 14]
le_m= Le_m ⁽⁰⁾(1-jα_mv_m/ I_m)
[0053]
le_m ⁽⁰⁾Is the vector effective length when nothing is connected to the port, and α_mIs a proportionality constant. In Equation 14, the vector effective length le_mIs a complex scalar representing the magnitude and phase of the current. However, in general, the vector effective length is a vector quantity in the real space, and has direction dependency. As described above, the vector effective length le of Expressions 12 and 14_mIs expanded from a complex scalar quantity to a vector quantity having direction dependency, thereby an array antenna apparatus 100 capable of changing the polarization as shown in FIG. 1 can be expressed.
[0054]
Therefore, as shown in FIG. 3, the vector effective length le of each of the parasitic elements A1 to A6 is set._mIs the vertical component le parallel to the z-axis._m ^VAnd a horizontal component le orthogonal to the z axis_m ^HThink separately. These vectors are vectors in the real space, and are different from the vectors representing the array arrangement of the antenna elements in the equivalent weight vector i 'and the like. As shown in FIG. 3, if the parasitic element Am has an inclination angle ω that is perpendicular to the vertical direction, the vertical component le of the vector effective length_m ^VAnd the horizontal component le_m ^HAre elevation angles θ = 90 and azimuth angles φ = φ, which are front directions of the respective parasitic elements Am._mAre represented as in Equations 15 and 16.
[0055]
[Equation 15]
le_m ^V= Le_mcos ω
(Equation 16)
le_m ^H= Le_msinω
[0056]
The dependence of the vector effective length on the direction (θ, φ) differs between the vertical component and the horizontal component of the vector effective length, and is expressed as in Expressions 17 and 18.
[0057]
[Equation 17]
le_m ^V(Θ, φ) = le_m ^Vf_m(Θ-90)
(Equation 18)
le_m ^H(Θ, φ) = le_m ^Hf_m(Φ-φ_m)
[0058]
Where f_m(Ξ) represents an element pattern. When the antenna element length is shorter than about half a wavelength, it can be approximated by Expression 19.
[0059]
[Equation 19]
f_m(Ξ) ≒ cos (ξ)
[0060]
Therefore, the vertical component le of the effective vector length of each parasitic element Am_m ^V(Θ, φ) is the vector effective length le_mFunction of the elevation angle of the array antenna based on_mThe horizontal component le of the vector effective length of each parasitic element Am calculated using (θ−90)_m ^H(Θ, φ) is the vector effective length le_mBased on the function f of the azimuth of the array antenna_m(Φ-φ_m).
[0061]
In the conventional array antenna device 150 shown in FIG. 36 and the array antenna devices described in Non-Patent Documents 4, 5, and 9, since the inclination angle ω of the antenna element from the vertical direction is 0, Since there is no more horizontally polarized component, the vector effective length is set to the scalar quantity le_m= Le_m ^VCould be treated as Further, as can be seen from Equations 17 and 19, the dependence of the vector effective length on the azimuth (θ, φ) is the same for all antenna elements, so that the element pattern f_m(Θ-90) could be considered separately. Further, the vector effective length le_mIs considered to be constant regardless of the antenna element, so the vector effective length le_mThat is, the array factor is calculated without considering the element pattern (see Non-Patent Document 2). On the other hand, as discussed above, the horizontal polarization component le of the vector effective length_m ^H(Θ, φ) is characterized in that the dependence on the azimuth angle φ differs depending on the antenna element Am as shown in Expression 18 because the direction of the antenna element changes.
[0062]
According to the above description, the vertical component le of the vector effective length of Expression 17_m ^VThe vertical component of the equivalent weight vector corrected by (θ, φ) is i^VAnd the horizontal component le of the vector effective length of Equation 18_m ^HThe horizontal component of the equivalent weight vector corrected by (θ, φ) is i^HAnd the equation of the received signal y (t) in Equation 4 is modified as follows.
[0063]
(Equation 20)
y (t) = ｛(i^V+ I^H)^Ta (θ, φ)｝ × u (t)
= ｛(I^V)^Ta (θ, φ)｝ × u (t)
+ ｛(I^H)^Ta (θ, φ)｝ × u (t)
= E^V× u (t) + E^H× u (t)
[0064]
Where E^V= ｛(I^V)^Ta (θ, φ)} represents the vertical component of the array factor,^H= ｛(I^H)^Ta (θ, φ)} represents the horizontal component of the array factor. Therefore, the array factor E (θ, φ) in Expression 13 is expressed by the vertical component E^VAnd the horizontal component E^HAnd can be expressed as the sum of
[0065]
(Equation 21)
E (θ, φ) = E^V+ E^H
[0066]
Hereinafter, the vertical component E of the array factor^VIs called the vertical component of the electric field of the array antenna device 100, and the horizontal component E of the array factor.^HCan be referred to as a horizontal component of the electric field of the array antenna device 100. Therefore, the former is the directional characteristic in the vertical plane of the array antenna device 100, and the latter is the directional characteristic in the horizontal plane. That is, the directional characteristics of the array antenna device 100 can be calculated using the following procedure.
[0067]
(1) In the array antenna device 100, the admittance matrix Y composed of the admittances between the elements A0 to A7 (these seven elements) including the excitation element A0 and the non-excitation elements A1 to A6, and the variable reactance elements Based on the reactance matrix X including the reactance values of 12-1 to 12-6, the equivalent weight vector i of the array distribution of the current flowing through each of the elements A0 to A7 is calculated using Expression 5.
(2) Vector effective length le of each of the elements A0 to A7 when the variable reactance elements 12-1 to 12-6 are not loaded_m ⁽⁰⁾And the port current and the port voltage on each of the variable reactance elements 12-1 to 12-6, and using the above equation 14, the vector effective length le of each of the elements A0 to A7._mIs calculated.
(3) The calculated vector effective length le of each of the elements A0 to A7_m, The vector effective length le of each of the elements A0 to A7_mAnd the inclination angle ω of each of the non-excitation elements A1 to A7 with respect to the excitation element A0, the elevation angle φ which is an inclination angle from a direction parallel to the excitation element A0, and the azimuth θ in a plane orthogonal to the non-excitation element A0. Using the equation (Equation 15 to Eq. 19) indicating the relationship, the component le of the vector effective length of each element A0 to A7 parallel to the excitation element A0_m ^V(Θ, φ) and a component le of a vector effective length orthogonal to the excitation element A0_m ^H(Θ, φ) is calculated.
(4) The component le of the vector effective length parallel to the excitation element A0 for each of the calculated elements A0 to A7_m ^V(Θ, φ) and a component le of a vector effective length orthogonal to the excitation element A0_m ^H(Θ, φ) is multiplied by the calculated equivalent weight vector i and multiplied by the steering vector a (φ, θ) indicating the radiation direction of the array antenna apparatus 100 (Equations 12 and 13 above). Is used.), And a directional characteristic E in a vertical plane parallel to the excitation element A0.^v(Θ, φ) and the directional characteristic E in the horizontal plane orthogonal to the excitation element A0.^H(Θ, φ) is calculated.
[0068]
In the calculation of the directional characteristics, as will be described later in detail, the vector effective length le_mIs multiplied by a correction coefficient γ that is substantially 1.1 to obtain a vector effective length le_mIs preferably corrected, whereby the calculation accuracy of the directional characteristics can be greatly improved.
[0069]
By the way, in the conventional array antenna apparatus 150, the horizontal polarization component of the incoming radio signal could not be received.^V× u (t) only could be obtained. On the other hand, in the array antenna apparatus 100 of the present embodiment, as can be seen from Equation 20, both the vertical polarization component and the horizontal polarization component of the incoming radio signal are included in the received signal y (t). Therefore, the antenna gain of the array antenna device 100 is expected to be improved as compared with the array antenna device 150 of the related art.
[0070]
FIG. 4 is a table showing a concept considered when calculating the vector effective length in the array antenna device according to the present invention and the array antenna device according to the related art. In particular, this table summarizes the progress of the extension of the concept of the vector effective length in the equivalent weight vector expression for the array antenna so far. First, the present inventors have found in Non-Patent Documents 4 and 5 (referred to as a first conventional example) that the current distribution on the elements of an array antenna is not constant, and proposed the introduction of a vector effective length. It was shown that the vector effective length was almost proportional to the reactance value of the variable reactance element loaded on each parasitic element. Since the direction dependencies are all the same, they were separately discussed as element patterns. Next, in Non-Patent Document 6 (referred to as a second conventional example), the present inventors have determined that the vector effective length of the array antenna is the port current i._mAnd voltage v_mIt is shown that At this stage, the vector effective length has been extended to a complex number and has phase information. Then, in the equivalent weight vector expression for the array antenna device 110 according to the present embodiment, in addition to the content of the second conventional example, the vector characteristic in real space, the direction dependency, and the vector effective length are further determined. Was introduced.
[0071]
The adaptive control type controller 20 of FIG. 1 controls the array antenna device 100 using a predetermined evaluation function based on the above principle. Hereinafter, a method of controlling the array antenna device 100 by the adaptive control type controller 20 when using some evaluation functions will be described.
[0072]
In the embodiment already described with reference to FIG. 1, the adaptive control type controller 20 receives the learning sequence signal included in the radio signal transmitted from the counterpart transmitter by the excitation element A0 of the array antenna device 100. A predetermined evaluation function value is calculated based on the received signal y (t) at the time and the learning sequence signal r (t) generated by the learning sequence signal generator 21 having the same signal pattern as the learning sequence signal. Then, adaptive control processing by the steepest gradient method was performed. At this time, a cross-correlation coefficient between the received signal y (t) and the learning sequence signal r (t) defined by the following equation can be used as the evaluation function (see Non-Patent Document 7).
[0073]
(Equation 22)

[0074]
Here, the continuous time parameter t is represented by a discrete parameter n. y (n) represents a vector composed of reception signals of predetermined P symbols received from predetermined time n, and r (n) is a learning sequence of predetermined P symbols received from time n. The adaptive control type controller 20 expresses the evaluation function value J based on the vectors y (n) and r (n) by using Expression 22.₁Is calculated. The adaptive control type controller 20 sequentially perturbs the reactance value of the variable reactance element by a predetermined difference width, and for each reactance value, the evaluation function value J₁, And the calculated evaluation function value J₁, The evaluation function value J using the steepest gradient method, for example.₁Is calculated so that each reactance value is maximized, so that each variable reactance element for directing the main beam of the array antenna apparatus 100 in the direction of the desired wave and nulling in the direction of the interference wave. Control is performed to calculate and set the reactance value. Thereby, the bias voltage value of each variable reactance element for directing the main beam of the array antenna apparatus 100 in the direction of the desired wave and nulling in the direction of the interference wave is searched so that the evaluation function value becomes the maximum. Then, the control voltage signal having the searched bias voltage value is output to each variable reactance element and set.
[0075]
Instead, the adaptive control type controller 20 can use an evaluation function that does not require the learning sequence signal r (t) and can be calculated only from the received signal y (t). Such estimation of the reactance value is called blind estimation. In this case, the learning sequence signal generator 21 can be eliminated from the configuration of FIG. As such an evaluation function, for example, the equation of Equation 23 disclosed in Non-Patent Document 7 and the equations of Equation 24 and Equation 25 disclosed in Non-Patent Document 8 can be used.
[0076]
(Equation 23)

[Equation 24]

(Equation 25)

[0077]
In Equation 23, the received signal y_p(N), (p = 1,..., P) correspond to the P symbols received from time n, and the evaluation function J₂Is the received signal y_pThis is an evaluation function based on maximizing the moment of (n). 24 evaluation function J₃Is the received signal y_nSecond moment E ｛| y_n|²｝ And fourth moment E ｛| y_n|⁴This is an evaluation function based on｝. In Equation 25, the received signal y_nIs an m-phase PSK signal, and the evaluation function J of Expression 25 is₄Is the received signal y_nIs a functional that represents the higher moment ratio of.
[0078]
The adaptive control type controller 20 sequentially perturbs the reactance value of the variable reactance element by a predetermined difference width, and evaluates each reactance value by an evaluation function J.₂Or J₄Is calculated, and based on the calculated evaluation function value, for example, by using the steepest gradient method, each reactance value is repeated so that the evaluation function value is maximized. By the calculation, the control is performed so as to calculate and set the reactance value of each variable reactance element for directing the main beam of the array antenna apparatus 100 in the direction of the desired wave and nulling in the direction of the interference wave. Thereby, the bias voltage value of each variable reactance element for directing the main beam of the array antenna apparatus 100 in the direction of the desired wave and nulling in the direction of the interference wave is searched so that the evaluation function value becomes the maximum. Then, the control voltage signal having the searched bias voltage value is output to each variable reactance element and set.
[0079]
When the evaluation functions of Expressions 23 to 25 are used, the learning sequence signal generator 21 is not required, so that the configuration of the control device of the array antenna device is simplified. The evaluation function that can be used by the application control type controller 20 is the evaluation function J described above.₁Or J₄It is not limited to only. Further, in the above embodiments, the steepest gradient method is used, but the present invention is not limited to this, and for example, iterative numerical solutions in nonlinear programming methods such as a sequential random method, a random method, and a high-dimensional bisection method Can be used.
[0080]
In the case of an array antenna for transmitting and receiving only a component of a radio signal that is polarized in one direction (for example, the array antenna device 150 in FIG. 36), instead of a half-wavelength dipole element, 1 / Although a four-wavelength monopole antenna element could be used, if a monopole antenna element inclined at an angle to the vertical direction is installed on the ground conductor, the vertically polarized wave will appear in the same direction in the mirror image of the radio wave. In order to transmit and receive a radio signal including a horizontal polarization component parallel to the ground conductor, a monopole non-exciting element provided on the ground conductor is used because horizontal polarization is reflected in the opposite direction and cancels each other. It is inappropriate. Therefore, only a half-wave dipole antenna element can be used as the non-excitation element of the present embodiment. However, a quarter-wave monopole antenna element on the ground conductor may be used as the excitation element. Of course, a dipole excitation element A0 can also be used.
[0081]
As described above, according to the control device of the array antenna device of the present embodiment, the array antenna that can change the antenna gain with respect to the polarization of the radio signal to be received and change the polarization of the radio signal to be transmitted The apparatus 100 is controlled, and particularly, at the time of reception, the polarization plane receivable by the array antenna apparatus 100 is matched with the polarization plane in the desired wave direction, and the interference wave is receivable by the array antenna apparatus 100. The array antenna device 100 can be controlled so that the polarization directions are orthogonal. Further, according to the equivalent weight vector expression of the array antenna described above, it is possible to provide an equivalent weight vector expression of the array antenna apparatus 100 in consideration of the nature and direction dependency of the vector. Thus, the directional characteristics of the array antenna device 100 can be calculated more accurately.
[0082]
<Second embodiment>
FIG. 5 is a perspective view illustrating a configuration of an array antenna device 110 according to a second embodiment of the present invention. FIG. 6 is a perspective view illustrating an array antenna device 111 according to a modification of the second embodiment of the present invention. It is a perspective view which shows a structure of. These embodiments are array antenna devices capable of changing the polarization so as to realize right-handed elliptical polarization and left-handed elliptical polarization symmetrically.
[0083]
In the array antenna device 110 of FIG. 5, in addition to the configuration of the array antenna device 100 of the first embodiment, the non-exciting elements A11 to A16 are respectively provided at positions where the non-exciting elements A1 to A6 are located on the circumference 200. The non-exciting elements A1 to A6 are arranged at an inclination angle opposite to the inclination angle ω (that is, −ω), and six pairs of cross-shaped dipole antennas are formed on the circumference 200 at predetermined intervals. . As in the first embodiment, the inclination angle ω is 0 ° <ω <90 °, and is preferably 45 °. Each of the non-excitation elements A11 to A16 is provided with a variable reactance element 12-11 to 12-16 at a central port in the longitudinal direction.
[0084]
In the wireless environment of FIG. 36, the circularly polarized (or elliptically polarized) wireless signal has its polarization turning direction reversed by reflection on the reflection surfaces S1, S2 and the like. For effective reception of a desired wave and removal of an interference wave, it is considered desirable to be able to receive any elliptically polarized wave of right or left rotation. From the simulation results described later, it can be seen that the array antenna device 100 of the first embodiment has a difference in the circularly polarized wave turning direction that is easy to form, but this is due to the non-excited element in the vertical direction in the array antenna device 100. Since the inclinations of A1 to A6 are only in one direction, that is, referring to FIG. 2, the non-exciting elements A1 to A6 are straight lines connecting the origin O to the longitudinal center of each of the non-exciting elements A1 to A6. It is considered that both are rotated in the positive direction at an angle ω with the rotation axis as a rotation axis. When the same reactance value is set, if the inclination angle of each non-excitation element is set to an angle −ω opposite to that of the first embodiment, a polarization direction opposite to that of the first embodiment can be obtained. .
[0085]
On the other hand, as described in Non-Patent Document 9, a dipole antenna element loaded with a variable reactance element can be electrically removed by giving an appropriate reactance value. That is, the vector effective length le in the direction orthogonal to the i-th (1 ≦ i ≦ 6) parasitic element Ai_iIs the reactance value X of the variable reactance element loaded on the i-th parasitic element._iUsing, le_i= Le_i ⁽⁰⁾(1-αX_i). Where le_i ⁽⁰⁾Is the vector effective length when the reactance value is 0 [Ω] or when no variable reactance element is loaded, and takes about 65% of the physical antenna element length. The proportionality constant α is a constant substantially determined by the structure of the antenna, particularly the length and thickness of the antenna element itself. From the above equation, the vector effective length does not depend on the array distribution (equivalent weight vector) of the current realized in the control result, but is determined by the reactance value which is a control parameter. Also, the reactance value X of the variable reactance element loaded on the parasitic element itself_iSince it is determined only by the value, it can be seen that the control can be performed independently of the reactance values of the other parasitic elements. Further, from the linearity of the above equation, the reactance value X_iIs set to a predetermined value so that the vector effective length le of the parasitic element Ai is independent of the state of the other parasitic elements._iCan always be set to 0. To summarize the above, by setting a reactance value such that an integral value of a current on a predetermined antenna element becomes substantially zero in a variable reactance element connected to the antenna element, a vector of the antenna element is set. The antenna element can be electrically removed by setting the effective length to substantially zero.
[0086]
Therefore, in order to transmit and receive right-handed elliptical polarization and left-handed elliptical polarization, an array antenna device as shown in FIG. 5 and FIG. suggest. The array antenna device 110 of FIG. 5 includes non-exciting elements A1 to A6 as antenna elements for right-handed elliptically polarized light, and non-exciting elements A11 to A16 as antenna elements for left-handed elliptically polarized light. When transmitting and receiving right-handed elliptically polarized radio signals, the non-excited elements A11 to A16 are electrically connected by setting appropriate reactance values to the variable reactance elements 12-11 to 12-16 according to the method described in Non-Patent Document 9. And control the reactance values of the variable reactance elements 12-1 to 12-6 loaded on the non-excitation elements A1 to A6 in the same manner as in the first embodiment to form a right-handed elliptically polarized wave. . Similarly, when transmitting and receiving a radio signal of left-handed elliptical polarization, the parasitic elements A1 to A6 are set by setting appropriate reactance values to the variable reactance elements 12-1 to 12-6 according to the method described in Non-Patent Document 9. By electrically removing and controlling the reactance values of the variable reactance elements 12-11 to 12-16 loaded on the parasitic elements A11 to A16 as in the first embodiment, a left-handed elliptically polarized wave can be formed. it can. The directional characteristics in the horizontal plane of the array antenna device 110 are symmetric between right-handed elliptical polarization and left-handed elliptical polarization.
[0087]
That is, in the array antenna device 111 of FIG. 5, non-exciting elements A1 to A6 as antenna elements for right-handed elliptical polarization and non-exciting elements A11 to A16 as antenna elements for left-handed elliptical polarization are included. , Are alternately arranged with different polarizations at a predetermined same interval on the circumference 200, so that it can be said that the different polarization alternate arrangement type is used.
[0088]
In the array antenna device 111 of FIG. 6, the parasitic elements A21 to A26 are shifted by 30 degrees on the circumference 200 from the positions of the parasitic elements A1 to A6, respectively, so that the adjacent parasitic elements A1 and A2 are shifted. , The position between adjacent parasitic elements A2 and A3, the position between adjacent parasitic elements A3 and A4, the position between adjacent parasitic elements A4 and A5, the adjacent parasitic elements A5 and A6 5 and the position between adjacent parasitic elements A6 and A1, the same effect as that of the array antenna device 110 of FIG. 5 can be obtained. That is, in the array antenna device 111 of FIG. 6, in addition to the configuration of the array antenna device 100 of the first embodiment, each of the parasitic elements A1 to A6 is shifted by 30 ° on the circumference 200 from the parasitic elements A1 to A6. A21 to A26 are arranged at an inclination angle -ω opposite to that of the parasitic elements A1 to A6. The non-exciting elements A21 to A26 are loaded with variable reactance elements 12-21 to 12-26, respectively, at their central ports in the longitudinal direction. The array antenna device 111 includes non-exciting elements A1 to A6 as antenna elements for right-handed elliptically polarized light, and non-exciting elements A21 to A26 as antenna elements for left-handed elliptically polarized light. Similar to the array antenna device 110 of FIG. 5, the array antenna device 111 includes one of a set of non-exciting elements A1 to A6 and a set of non-exciting elements A21 to A26, as described above. According to the described method, the signal is electrically removed, and the remaining set of parasitic elements can transmit and receive a right-handed elliptically polarized wave or a left-handed elliptically polarized radio signal.
[0089]
In the above embodiments, the array antenna devices 110 and 111 that transmit and receive elliptically polarized waves have been described. However, the array antennas that transmit and receive circularly polarized waves by changing the inclination angle ω and the reactance value of the variable reactance element. The device can be configured.
[0090]
Hereinafter, a description will be given of a control method when the array antenna device of FIG. 1 includes an array antenna device 110 instead of the array antenna device 100 of the first embodiment.
[0091]
An input device 22 such as a keyboard is connected to the adaptive control type controller 20. Before starting the wireless communication using the demodulator or the wireless transmitter 7, the user uses the input device 22 to electrically connect the non-excited elements A1 to A6 or the non-excited elements A11 to A16. A set of parasitic elements to be removed is selected and input, and in response thereto, an instruction signal including the instruction content is input from the input device 22 to the adaptive control type controller 20. The adaptive control type controller 20 outputs a reactance value such that the integral value of the current on the selected parasitic element becomes substantially zero to a variable reactance element connected to the parasitic element to set the reactance value. Thereby, the vector effective length of the parasitic element is made substantially zero, and the parasitic element is electrically removed.
[0092]
Also at the time of transmission, based on the instruction signal from the input device 22, the integrated value of the current on the set of passive elements (A1 to A6 or A11 to A16) selected by the user becomes substantially zero. By setting such a reactance value to a variable reactance element connected to the parasitic element, the vector effective length of the parasitic element is made substantially zero, and the parasitic element is electrically connected. It can also be removed.
[0093]
After electrically removing any of the parasitic elements A1 to A6 or the parasitic elements A11 to A16, the adaptive control type controller 20 uses a predetermined evaluation function as in the first embodiment. , For directing the main beam of the array antenna device 110 or 111 in the direction of the desired wave and nulling in the direction of the interference wave, among the variable reactance elements, connected to a non-excited element that is not electrically removed. A bias voltage value applied to the variable reactance element is searched for and set using a control voltage signal.
[0094]
In the embodiment described above, the parasitic element to be electrically removed is set in advance by the user using the input device 22. Instead, the adaptive control type controller 20 automatically sets the parasitic element based on the received signal y (t). May also be set. At this time, the adaptive control type controller 20 assumes that the radio signal to be received is right-handed polarization and electrically removes the non-exciting elements A11 to A16, and the radio signal to be received is left-handed polarization. Then, a predetermined evaluation function value (for example, received signal power) for the received signal is compared with the case where the parasitic elements A1 to A6 are electrically removed assuming that. More specifically, the adaptive control type controller 20 electrically removes the parasitic elements A11 to A16 and adaptively controls the reactance values corresponding to the parasitic elements A1 to A6. The elements A1 to A6 are electrically removed and the reactance values corresponding to the non-excited elements A11 to A16 are compared with an evaluation function value when adaptively controlled, and the reactance corresponding to the larger evaluation function value is compared. Value, that is, a set of non-excited elements capable of receiving a polarization such that the evaluation function value becomes large (that is, a set of non-excited elements A1 to A6 or a set of non-excited elements A11 to A16) A reactance value that electrically removes the set of parasitic elements is set for each of the parasitic elements A1 to A6 and A11 to A16.
[0095]
Since it is not necessary to electrically remove one of the set of the parasitic elements A1 to A6 and the set of the parasitic elements A11 to A16, it is possible to effectively use the parameters of 6 × 2 reactance values. For example, the degree of freedom regarding the directional characteristics and the polarization is further improved. Also in this case, if the reactance values are exchanged for each pair of the non-excited elements A1, A11, A2 and A12,..., A6 and A16, the direction of the polarization is also reversed. This is because the vertical polarization does not change, but the direction of the horizontal polarization changes.
[0096]
As described above, according to the array antenna device of the present embodiment, it is possible to provide an array antenna device capable of transmitting and receiving a right-handed elliptically polarized radio signal and a left-handed elliptically polarized radio signal.
[0097]
<Third embodiment>
In the present embodiment, a description will be given of a linear array antenna device in which one or a plurality of non-exciting elements loaded with variable reactance elements are arranged and the polarization can be changed. The following embodiment can also be used in the control device of the array antenna device of FIG.
[0098]
FIG. 7 is a perspective view showing a configuration of an array antenna device 120 according to a third embodiment of the present invention. In the array antenna apparatus 120, a non-excitation element A41 is arranged in a direction that is not parallel and not orthogonal to the excitation element A0 in the vertical state, and the variable excitation element 12-41 (specifically, A variable capacitance diode is mounted, and the reactance value is controlled to change the polarization. Specifically, referring to the xyz coordinates in FIG. 7, the excitation element A0 of the half-wavelength dipole is arranged on the z-axis so that the center in the longitudinal direction is aligned with the origin O, and the non-excitation element A41 of the half-wavelength dipole is arranged. Are arranged side by side at a predetermined distance from the excitation element A0 in the positive direction of the x-axis such that the center in the longitudinal direction is located on the x-axis in a plane parallel to the yz plane. The non-exciting element A41 is rotated by a predetermined angle (for example, 45 °) from the vertical direction about the x-axis as the rotation axis, similarly to the first embodiment shown in FIG.
[0099]
In the array antenna apparatus 120, the radio signal radiated by the excitation element A0 and containing only the vertical polarization component excites the non-excitation element A41, and then the non-excitation element A41 converts the vertical polarization component and the horizontal polarization component. Can radiate radio waves, including: According to the array antenna device 120 of the present embodiment, the tilt angle with the x-axis as the rotation axis with respect to the excitation element A0, even if a plurality of non-excitation elements are not provided unlike the first and second embodiments. The presence of one or more parasitic elements having the above can change the polarization of a radio signal transmitted and received by the array antenna device.
[0100]
In the present embodiment, the non-exciting element A41 rotates around the x-axis as a rotation axis. However, the present invention is not limited to this. It may be configured to be shifted and inclined with respect to the excitation element A0. This is the same in a modified example of the third embodiment described below.
[0101]
FIG. 8 is a perspective view showing a configuration of an array antenna device 121 which is a first modification of the third embodiment according to the present invention. This array antenna device 121 is a linear array antenna device in which an excitation element A0 and two non-excitation elements A41 and A42 are arranged.
[0102]
In the array antenna device 121 of FIG. 8, by disposing the non-excitation element A42 before (not necessarily on a straight line) the non-excitation element A41 of FIG. The elements A41 and A42 are juxtaposed on the x-axis. Specifically, referring to the xyz coordinates in FIG. 8, the non-excitation element A42 of the half-wave dipole has a non-excitation element such that the center in the longitudinal direction is located on the x-axis in a plane parallel to the yz plane. It is arranged at a predetermined distance from the element A41 in the positive direction of the x-axis. The non-exciting element A42 is rotated by an angle different from that of the non-exciting element A41 in the vertical direction about the x-axis as a rotation axis. In the embodiment shown in FIG. 8, the non-exciting element A42 is rotated by 90 ° with respect to the exciting element A0.
[0103]
According to the array antenna device 121 configured as described above, gain improvement and increase in horizontal polarization component can be obtained. The added parasitic element A42 may be orthogonal to the excitation element A0 as shown in FIG. The non-excitation element A42 is not directly excited by the excitation element A0, but the horizontal polarization component increases due to the provision of the non-excitation element A42 because the non-excitation element A42 is replaced with the non-excitation element loaded with the variable reactance element 12-41. This is because it is possible to excite via the excitation element A41. Further, it is not always necessary to load the variable reactance element 12-42 on the additional parasitic element A42. Even when the variable reactance element 12-42 is not loaded, it is possible to operate as a director by designing it short beforehand and operate as a reflector by designing it long according to the principle of the Yagi Uda array antenna. Can be expected to reduce the complexity and cost of
[0104]
FIG. 9 is a perspective view showing a configuration of an array antenna device 122 which is a second modification of the third embodiment according to the present invention. The array antenna device 122 is a linear array in which three or more non-excitation elements are arranged before and after the excitation element A0.
[0105]
In the array antenna device 122, specifically, referring to the xyz coordinates in FIG. 9, in addition to the configuration of the array antenna device 121 in FIG. 8, a parasitic element A43 is further provided in the positive direction of the x-axis. Parasitic elements A39 and A38 are further provided in the negative direction of the axis. Here, the excitation element A0 and the non-excitation elements A41, A42, A38, and A39 are juxtaposed on the x-axis. The parasitic element A43 of the half-wavelength dipole is separated from the parasitic element A42 by a predetermined distance in the positive direction of the x axis so that the center in the longitudinal direction is located on the x axis in a plane parallel to the yz plane. Be placed. The non-exciting element A43 is rotated about the x axis by a different angle (for example, 135 °) with respect to the vertical direction from the non-exciting elements A41 and A42. A variable reactance element 12-43 is loaded on a central port in the longitudinal direction of the non-exciting element A43.
[0106]
Further, it is not necessary to dispose a plurality of non-excitation elements only in front of the excitation element A0 (positive direction of the x-axis), and as shown in the figure, also behind the excitation element A0 (negative direction of the x-axis). By operating them as reflectors, the gain of the array antenna device can be improved. The non-exciting element A39 of the half-wave dipole is arranged at a predetermined distance in the negative x-axis direction from the exciting element A0 such that the center in the longitudinal direction is located on the x-axis in a plane parallel to the yz plane. Is done. The non-exciting element A39 is rotated around the x-axis by a different angle (for example, −45 °) with respect to the vertical direction from the non-exciting elements A41 to A43. A variable reactance element 12-39 is loaded in the central port in the longitudinal direction of the non-exciting element A39. Similarly, the parasitic element A38 of the half-wave dipole is located at a predetermined distance from the parasitic element A39 in the negative direction of the x axis such that the center in the longitudinal direction is located on the x axis in a plane parallel to the yz plane. Just placed away. The non-exciting element A38 is rotated by an angle (for example, −90 °) different from that of the non-exciting element A39 in the vertical direction about the x-axis as the rotation axis. A variable reactance element 12-38 is loaded on a central port in the longitudinal direction of the non-exciting element A38.
[0107]
According to the array antenna device 122, the degree of freedom and the gain of the polarization control can be improved in accordance with the principle of the Yagi-Uda array antenna. It is not necessary to arrange each antenna element linearly. Also, some parasitic elements (parasitic elements A42 and A38 in the embodiment of FIG. 9) can be arranged orthogonal to the exciting element A0. Further, in order to simplify the process of controlling a plurality of reactance values, it is not necessary to load the variable reactance elements on all the non-excitation elements.
[0108]
<Fourth embodiment>
FIG. 10 is a perspective view illustrating a configuration of an array antenna device 130 according to a fourth embodiment of the present invention. The array antenna apparatus 130 is an array antenna apparatus in which non-excitation elements are arranged doubly around an excitation element A0 and can change the polarization. This embodiment can also be used in place of the array antenna device 100 in the control device for the array antenna device of FIG.
[0109]
Referring to the xyz coordinates shown in FIG. 10, the array antenna device 130 has an xy plane having a radius larger than the circumference 200 around the origin O in addition to the configuration of the array antenna device 100 of the first embodiment. And a half-wavelength dipole non-exciting elements A51 to A56 arranged on the inner circumference 210. The non-exciting elements A51 to A56 are arranged so that the longitudinal direction thereof is aligned with the tangential direction of the circumference 210, and the center of the non-exciting element A51 in the longitudinal direction is an extension between the origin O and the longitudinal center of the non-exciting element A1. The center of the non-exciting element A52 in the longitudinal direction is located on the line, and is located on an extension of the origin O and the center of the non-exciting element A2 in the longitudinal direction. The same applies to the non-exciting elements A53 to A56.
[0110]
In the embodiment of the array antenna apparatus 130 in FIG. 10, the non-exciting elements A1 to A6 and A51 to A56 are arranged on two circumferences having different radii. They may be arranged in quadruple or the like. Thereby, the degree of freedom and the gain of the polarization control can be improved. In a single case (that is, a case similar to the first embodiment), the excitation of the horizontal polarization component is weak because the excitation element A0 is a vertically polarized wave. As described above, in the first embodiment, the non-excitation elements A1 to A6 must not be orthogonal to the excitation element A0. Therefore, by disposing the non-exciting elements A51 to A56 of the dipole horizontally on the outer circumference 210 as shown in FIG. 10, the horizontal polarization is increased, and for example, the circular polarization axis ratio (vertical component and horizontal component Level difference) can be improved. Further, the non-exciting elements A51 to A56 on the outer circumference 210 do not need to be loaded with the variable reactance element. Thereby, complication of control can be avoided.
[0111]
<Fifth embodiment>
FIG. 11 is a perspective view illustrating a configuration of an array antenna device 140 according to a fifth embodiment of the present invention. This embodiment can also be used in place of the array antenna device 100 in the control device for the array antenna device of FIG.
[0112]
The array antenna device 140 has the same configuration as that of the array antenna device 130 of the fourth embodiment, except that the parasitic elements A11 to A16 are respectively located at positions where the parasitic elements A1 to A6 are located on the circumference 200. Arranged at an inclination angle opposite to A1 to A6 (that is, −ω), and six cross-shaped dipoles are formed on the circumference 200. Each of the non-excitation elements A11 to A16 is provided with a variable reactance element 12-11 to 12-16 at a central port in the longitudinal direction. Therefore, the array antenna device 140 can realize symmetric polarization of right-handed rotation and left-handed rotation by providing the non-exciting elements A1 to A6 and A11 to A16 similarly to the second embodiment. In the same manner as in the embodiment, six pairs of cruciform dipole antennas are provided on the circumference 200 at predetermined predetermined intervals, and the longitudinal direction is parallel to the tangent of the circumference 210 on the circumference 210. By providing the passive elements A51 to A56 at predetermined intervals, it is possible to configure an array antenna device having a double array of passive elements and capable of changing the polarization.
[0113]
As can be seen from the simulation results described later, the right-handed elliptical polarization is easily realized in the array antenna apparatus 100 of FIG. 1, but the left-handed polarization is hardly realized. Therefore, in order to realize a symmetric polarization characteristic, a pair in which the inclination angle of the arrangement of the inner parasitic elements is symmetric is arranged. The horizontal dipole passive elements A51 to A56 added on the outer circumference 210 operate similarly for the set of passive elements A1 to A6 or for the set of passive elements A11 to A16. Therefore, an effect of increasing the horizontal polarization component is similarly obtained for a right-handed or left-handed polarized radio signal.
[0114]
【Example】
In the following simulation, the equivalent weight vector expression of the array antenna device 100 of the first embodiment is verified. The seven-element array antenna device 100 shown in FIG. 2 is analyzed. The thickness of each antenna element is 0.02λ, the interval between each antenna element in the xy plane is λ / 4, the element length of the non-exciting elements A1 to A6 is λ / 2, and the Element length is λ / 2^3/2And The inclination angles ω of the parasitic elements A1 to A6 are all equal to 45 degrees. The height in the z-axis direction of the excitation element A0 and the non-excitation elements A1 to A6 was set to be equal. FIG. 12 is a table showing the electrical structure parameters of the array antenna device 100. The table of FIG. 12 shows an admittance element Y which is an electrical structure parameter obtained by calculating the array antenna apparatus 100 having this structure by the moment method._ijAnd the vector effective length le of the excitation element A0 when the coaxial cable 5 is not connected to the power supply port of the excitation element A0.₀ ⁽⁰⁾And the effective vector length le of the parasitic element Am when the reactance value is 0Ω._m ⁽⁰⁾And the proportionality constant α of Equation 14_mAre shown.
[0115]
Since the non-exciting elements A1 to A6 have the inclination angle ω, the symmetry with respect to the xz plane of the structure of the conventional array antenna device 150 having only the vertical polarization plane is lost, Due to the existence of rotational symmetry, the admittance element Y_ijHas been found to maintain the symmetry shown in Equation 26.
[0116]
(Equation 26)
Y₁₂= Y₁₆
[Equation 27]
Y_Thirteen= Y_Fifteen
[0117]
Therefore, the independent admittance element Y_ijAre only six shown in the table of FIG. Also, the vector effective length le_m ⁽⁰⁾And the proportionality constant α_mWas calculated from the admittance distribution on the antenna element according to Non-Patent Document 5. As a result, in Non-patent Documents 4 and 5, the proportionality constant α_mWas almost a real number, but when the antenna elements were arranged obliquely as in the present embodiment, it was found that the imaginary part was so large that it could not be ignored. Therefore, in the array antenna device 100 analyzed in the present embodiment, Give as a complex number.
[0118]
FIGS. 13 and 14 show the array antenna apparatus when the reactance values of the cases C1 and C2 shown in Table 1 below are set for the array antenna apparatus 100 having the parameters shown in FIG. It is a graph which shows 100 directional characteristic patterns in a horizontal plane, respectively.
[0119]
[Table 1]

[0120]
When the reactance value of Case 1 is set in each of the variable reactance elements 12-1 to 12-6 of the array antenna device 100, a sector pattern having a predetermined main beam azimuth and a beam width in the array antenna device 100 is obtained. The reactance values of Case 2 are randomly selected to form.
[0121]
13 and FIG.^VThe curve shown by indicates the vertical polarization component of the electric field, and E^HThe curve shown by represents the horizontal polarization component of the electric field. It can be seen that the ratio of vertical polarization to horizontal polarization changes depending on the azimuth angle φ. This is because, as described above, when the directions of the vertically polarized waves to be excited are the same between the non-excited elements arranged at positions opposite to the excited element A0, the directions of the horizontally polarized waves are opposite. The polarization realized on the array antenna apparatus 100 is consistent with the content considered to be different depending on the direction. Solid curve E^V(Mom) and E^H(Mom) indicates the electric field calculated by the moment method, and is indicated by a coarse broken line E.^V(Le) and E^H(Le) shows the electric field calculated from the equivalent weight vector. Both are almost the same. From this, it was confirmed that by treating the vector effective length as a real space vector having direction dependency, the array antenna apparatus 100 capable of changing the polarization can be expressed using the equivalent weight vector.
[0122]
However, in particular, the directivity characteristics of the vertical polarization do not match as much as those described in Non-Patent Document 5. To investigate the cause, the current distribution i on the element calculated by the moment method_m(Z) and the port current i obtained by calculating the equivalent weight vector_m(0) is shown in FIGS. FIG. 15 shows a current distribution i on each antenna element when the reactance value of case C1 is set in array antenna apparatus 100._m(Z) and port current i_mFIG. 16 is a graph showing the amplitude of (0), and FIG. 16 shows the current distribution i on each antenna element when the reactance value of the case C1 is set in the array antenna apparatus 100._m(Z) and port current i_mIt is a graph which shows the phase of (0). FIG. 17 shows a current distribution i on each antenna element when the reactance value of case C2 is set in array antenna apparatus 100._m(Z) and port current i_mFIG. 18 is a graph showing the amplitude of (0). FIG. 18 shows the current distribution i on each antenna element when the reactance value of the case C2 is set in the array antenna apparatus 100._m(Z) and port current i_mIt is a graph which shows the phase of (0). Port current i for both methods_mIt can be seen that (0) matches well with both amplitude and phase.
[0123]
Next, the calculation result of the vector effective length is examined. FIG. 19 is a graph showing the vector effective length of each antenna element when the reactance value of case C1 is set in the array antenna device 100. FIG. 20 is a graph showing the reactance value of case C2 set in the array antenna device 100. 9 is a graph showing a vector effective length of each antenna element when the operation is performed. FIGS. 19 and 20 show the vector effective length le of the excitation element A0.₀Vector effective length le normalized by_mThe real part and the imaginary part of are shown. The calculation results by the moment method are shown by hollow symbols (open squares □ and 45 ° rotated squares ◇), and the calculation results by the equivalent weight vector of Equation 14 are filled with hollow symbols (circles ● and ■). There is no significant difference here, and it can be seen from Equation 14 that the current distribution on the element is accurately expressed. In the directional characteristics of FIGS. 13 and 14, since the shape of the directional characteristics of the horizontal polarization matches well with that of the vertical polarization, the difference is caused by the radiation wave of the excitation element A0 that does not contribute to the horizontal polarization. Can be guessed. Since the radiation wave is omnidirectional, its size remains as a candidate. Therefore, for correction, a value obtained by relatively multiplying the vector effective length of the excitation element A0 by γ is added to the new vector effective length le._m ⁽⁰⁾’.
[0124]
[Equation 28]
le_m ⁽⁰⁾’= Γle_m ⁽⁰⁾
[0125]
The results obtained when the correction coefficient γ = 1.1 are shown in FIGS.^V(Le ') and E^H(Le '). The results close to the calculation results of the moment method are obtained for both vertically polarized waves and horizontally polarized waves. From this, it can be seen that it is necessary to evaluate the vertical polarization radiated from the non-exciting elements A1 to A6 having the inclination of 45 degrees to be small in order to match the calculation result of the moment method. It is assumed that the element patterns of all the antenna elements are equal as shown in Expression 19, but as shown in the table of FIG. 12, the excitation element A0 and the non-excitation elements A1 to A6 have a vector effective length le._m ⁽⁰⁾When the difference is large, the current distributions on the elements are different and the element patterns are not equal. Therefore, there is a possibility that the correction of the correction coefficient γ = 1.1 is required due to the difference in the element patterns. That is, in the most preferred embodiment, the correction coefficient γ is 1.1, but preferably, the correction coefficient γ is more than 1.0 and equal to or less than 1.2, and more preferably, the correction coefficient γ is 1.05 or less. It is not less than 1.15.
[0126]
Next, paying attention to the horizontal direction of the parasitic element A0 (φ = 0 °) and the direction between the parasitic elements A1 and A2 (φ = 30 °), the variable polarization in the array antenna apparatus 100 is changed. Examine the ability to form waves and beam patterns. The steepest gradient method is used because it is difficult to analytically find the optimal solution because the current array arrangement (equivalent weight vector) that can be realized by the combination of reactance values is not clear (see Non-Patent Documents 10 and 11). . However, the convergence state obtained by the steepest gradient method is not always the optimal solution. There is no limitation on the range in which the reactance value can be changed. The initial value of the reactance value in the repetition is as follows: when focusing on the parasitic element A1 (φ = 0), the reactance value of the parasitic element A1 is -100Ω, and the reactance values of the other parasitic elements A2 to A6 are 0Ω. When focusing on the direction (φ = 30) between the parasitic elements A1 and A2, the reactance values of the parasitic elements A1 and A2 are set to −100Ω, and the reactance values of the other parasitic elements A3 to A6 are set to 0Ω. In the calculation of the vector effective length, the correction coefficient γ was set to 1.1 using Equation 28. A quantity such as Equations 29 to 35 is used as the evaluation function to be maximized.
[0127]
(Equation 29)
| E^V|
[Equation 30]
| E^H|
[Equation 31]
| E^V|-| E^H|
(Equation 32)
| E^V|-| E^V|
[Equation 33]
| E^V+ JE^H|
[Equation 34]
| E^V−jE^H|
(Equation 35)
| E^V| + | E^H|
[0128]
Here, the vertical polarization component E of the electric field^VAnd the horizontal polarization component E^HIs defined by the following equation.
[0129]
[Equation 36]

(37)

[0130]
Here, a correction coefficient γ ≒ 1.1, k is a propagation constant 2π / λ, d is an interval between antenna elements, which is λ / 4 in the present embodiment, and an azimuth angle φ_mIs represented by the following equation.
[Equation 38]
φ_m= 2π (m-1) / 6
m = 1, ..., 6
[0131]
Equation 29 is a condition for increasing vertical polarization, Equation 30 is for horizontal polarization, Equation 33 is for left-hand circular polarization, and Equation 34 is for right-hand circular polarization. Further, Equation 31 is the cross polarization discrimination degree of the horizontal polarization with respect to the vertical polarization, Equation 32 is the cross polarization discrimination degree of the vertical polarization with respect to the horizontal polarization, and Equation 35 is the condition that the radiated power becomes strong. . FIG. 21 is a table showing the respective convergent reactance values when the adaptive control type controller 20 uses different evaluation functions when the desired wave direction is set to 0 ° and 30 °. FIGS. 22 to 35 are graphs showing directivity patterns in the horizontal plane when the convergent reactance values corresponding to the respective desired wave directions and the respective evaluation functions in FIG. 21 are set in the array antenna apparatus 100. 22 to 35, the results calculated by the moment method using the reactance values in the table of FIG.^V(Mom) and E^H(Mom), and the result of the equivalent weight vector expression taking into account the vector effective length after correcting equation 28 is shown by the broken line E^V(Le ') and E^H(Le '). The vertical polarization component E^V(Mom) and E^V(Le ') is a thin line, and the horizontal polarization component E^H(Mom) and E^H(Le ') is indicated by a thick line.
[0132]
The result of the convergent reactance value agrees well with the result of the moment method, confirming the effectiveness of the equivalent weight vector expression using the extended vector effective length and the optimization method using the steepest gradient method. Overall, the level of horizontal polarization is lower than that of vertical polarization. This is because a horizontally polarized component is not radiated from the excitation element A0 through which a large current flows. Therefore, vertical polarization plays a dominant role in determining the convergence state of the evaluation function. However, it can be seen from the evaluation function of Equation 32 that it is possible to make the horizontal polarization stronger than the vertical polarization in the direction where the parasitic element is located and in the direction between the parasitic elements. Conversely, horizontal polarization is suppressed, and vertical polarization having a cross polarization discrimination of about 13 dB can be realized. When the value of Equation 34 is used as the evaluation function value, a circular polarization axis ratio of 1.9 (5.6 dB) in the 0-degree direction and 2.0 (6.0 dB) in the 30-degree direction is obtained. A circularly polarized wave with a good axial ratio has not been obtained. Further, when trying to realize right-handed polarization, the horizontal polarization component increases, but when trying to realize left-handed polarization, the horizontal polarization decreases. Also, the convergence results of Equations 32, 34, and 35 become substantially equal. It is considered that these are due to the fact that the excitation phase of the horizontal polarization tends to advance from the vertical polarization of the central excitation element A0.
[0133]
As described above, according to the equivalent weight vector expression of the array antenna according to the embodiment, it is possible to provide an equivalent weight vector expression of the array antenna device in consideration of the properties of the vector and the direction dependency. Therefore, by using the equivalent weight vector expression, the directional characteristics of the array antenna device can be calculated more accurately.
[0134]
As described above, according to the array antenna device of the embodiment according to the present invention, by arranging the non-excitation element of the dipole at an angle, the polarization crossing the polarization plane of the radio signal transmitted and received by the excitation element An array antenna device having an antenna gain for (or orthogonal polarization) can be provided. By controlling the polarization, the transmission / reception intensity of the desired wave can be increased, and the degree of freedom in suppressing the interference wave can be increased. In addition, it was shown that the equivalent weight vector can be expressed by considering the characteristic and direction dependency of the real space vector in the vector effective length of the antenna element of the dipole. Furthermore, in the simulation, the steepness gradient method was used to examine the ability to change the polarization in the desired direction. From the simulation results, it was found that the horizontal polarization can be made stronger than the vertical polarization in the element direction and the inter-element direction. It was also found that circular polarization with an axial ratio of about 2 (6 dB) can be realized in a desired direction. Furthermore, an array antenna device in which dipole antenna elements having a symmetrical inclination are arranged in an overlapping manner in order to have a achievable symmetry in a circularly polarized wave turning direction has been proposed. As a result, it is possible to realize an array antenna device that can switch the polarization and has a high degree of freedom in setting the polarization.
[0135]
【The invention's effect】
As described in detail above, according to the array antenna device of the present invention, in the electronically controlled waveguide array antenna device or the linear array antenna device, at least one non-exciting element is inclined with respect to the exciting element. By providing, by transmitting and receiving the radio signal of the horizontal polarization component in addition to the vertical polarization component, by changing the reactance value of the variable reactance element, the vertical polarization component and the horizontal polarization component of the radio signal to be transmitted and received Control. Thereby, the polarization of the array antenna device can be changed. Therefore, even in a multipath environment such as the wireless environment shown in FIG. 36, wireless signals of various polarization components can be transmitted and received with a predetermined antenna gain or more.
[0136]
Further, according to the control method or apparatus of the array antenna apparatus according to the present invention, based on the received signal received by the excitation element of the array antenna apparatus, the reception method is performed by using an iterative numerical solution in a nonlinear programming method. Calculate the reactance value of the variable reactance element for directing the main beam of the array antenna in the direction of the desired wave and nulling in the direction of the interference wave so that the value of the predetermined evaluation function including the signal becomes maximum or minimum. And set. Therefore, even in a multipath environment such as the wireless environment shown in FIG. 36, wireless communication can be performed by setting the radiation pattern of the array antenna device and its polarization to substantially the best state.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a control device of an array antenna device according to a first embodiment of the present invention.
FIG. 2 is a perspective view showing a detailed configuration of the array antenna device 100 of FIG.
FIG. 3 is a diagram showing an inclination angle ω of the parasitic element A1 of FIG. 2 from a vertical direction, and a vertical component and a horizontal component of a vector effective length.
4 is a table showing a concept considered when calculating a vector effective length in the array antenna device 100 of FIG. 1 and a conventional array antenna device.
FIG. 5 is a perspective view showing a configuration of an array antenna device 110 according to a second embodiment of the present invention.
FIG. 6 is a perspective view showing a configuration of an array antenna device 111 which is a modification of the second embodiment according to the present invention.
FIG. 7 is a perspective view illustrating a configuration of an array antenna device 120 according to a third embodiment of the present invention.
FIG. 8 is a perspective view showing a configuration of an array antenna device 121 which is a first modification of the third embodiment according to the present invention.
FIG. 9 is a perspective view showing a configuration of an array antenna device 122 which is a second modification of the third embodiment according to the present invention.
FIG. 10 is a perspective view showing a configuration of an array antenna device 130 according to a fourth embodiment of the present invention.
FIG. 11 is a perspective view showing a configuration of an array antenna device 140 according to a fifth embodiment of the present invention.
FIG. 12 is a table showing electrical structure parameters of the array antenna device 100 of FIG. 1;
13 is a graph showing a simulation result of the control device of the array antenna device of FIG. 1 and showing a directional characteristic pattern in a horizontal plane when the reactance value of the case C1 is set in the array antenna device 100. FIG.
14 is a graph showing a simulation result of the control device of the array antenna device of FIG. 1 and showing a directional characteristic pattern in a horizontal plane when the reactance value of the case C2 is set in the array antenna device 100. FIG.
FIG. 15 is a simulation result of the control device of the array antenna device of FIG. 1, and shows a current distribution i on each antenna element when the reactance value of the case C1 is set in the array antenna device 100;_m(Z) and port current i_mIt is a graph which shows the amplitude of (0).
FIG. 16 is a simulation result of the control device of the array antenna device of FIG. 1, and shows a current distribution i on the element of each antenna element when the reactance value of the case C1 is set in the array antenna device 100;_m(Z) and port current i_mIt is a graph which shows the phase of (0).
FIG. 17 is a simulation result of the control device of the array antenna device of FIG. 1 and shows a current distribution i on the element of each antenna element when the reactance value of the case C2 is set in the array antenna device 100;_m(Z) and port current i_mIt is a graph which shows the amplitude of (0).
FIG. 18 is a simulation result of the control device of the array antenna device of FIG. 1, and shows a current distribution i on the element of each antenna element when the reactance value of the case C2 is set in the array antenna device 100;_m(Z) and port current i_mIt is a graph which shows the phase of (0).
19 is a graph showing a simulation result of the control device of the array antenna device of FIG. 1 and showing a vector effective length of each antenna element when the reactance value of the case C1 is set in the array antenna device 100. FIG.
20 is a graph showing a simulation result of the control device of the array antenna device of FIG. 1 and showing a vector effective length of each antenna element when the reactance value of the case C2 is set in the array antenna device 100. FIG.
21 is a table showing simulation results of the control device of the array antenna device of FIG. 1 and showing respective convergent reactance values when the adaptive control type controller 20 uses different evaluation functions.
FIG. 22 is a simulation result of the control device of the array antenna device of FIG. 1, where a desired wave direction φ = 0 ° and an evaluation function | E^V6 is a graph showing a directional characteristic pattern in a horizontal plane when a convergent reactance value when | is set in the array antenna device 100.
23 is a simulation result of the control device of the array antenna device of FIG. 1, which shows a desired wave direction φ = 0 °, and an evaluation function | E.^H6 is a graph showing a directional characteristic pattern in a horizontal plane when a convergent reactance value when | is set in the array antenna device 100.
24 is a simulation result of the control device of the array antenna device of FIG. 1, which shows a desired wave direction φ = 0 °, and an evaluation function | E.^V|-| E^H6 is a graph showing a directional characteristic pattern in a horizontal plane when a convergent reactance value when | is set in the array antenna device 100.
FIG. 25 is a simulation result of the control device of the array antenna device of FIG. 1, which shows a desired wave direction φ = 0 °, and an evaluation function | E.^H|-| E^V6 is a graph showing a directional characteristic pattern in a horizontal plane when a convergent reactance value when | is set in the array antenna device 100.
26 is a simulation result of the control device of the array antenna device of FIG. 1, where a desired wave direction φ = 0 ° and an evaluation function | E^V+ JE^H6 is a graph showing a directional characteristic pattern in a horizontal plane when a convergent reactance value when | is set in the array antenna device 100.
27 is a simulation result of the control device of the array antenna device of FIG. 1, where a desired wave direction φ = 0 ° and an evaluation function | E^V−jE^H6 is a graph showing a directional characteristic pattern in a horizontal plane when a convergent reactance value when | is set in the array antenna device 100.
FIG. 28 is a simulation result of the control device of the array antenna device of FIG. 1, where a desired wave direction φ = 0 ° and an evaluation function | E^V| + | E^H6 is a graph showing a directional characteristic pattern in a horizontal plane when a convergent reactance value when | is set in the array antenna device 100.
FIG. 29 is a simulation result of the control device of the array antenna device of FIG. 1, where a desired wave direction φ = 0 ° and an evaluation function | E^V6 is a graph showing a directional characteristic pattern in a horizontal plane when a convergent reactance value when | is set in the array antenna device 100.
30 is a simulation result of the control device of the array antenna device of FIG. 1, where a desired wave direction φ = 30 °, and an evaluation function | E^H6 is a graph showing a directional characteristic pattern in a horizontal plane when a convergent reactance value when | is set in the array antenna device 100.
31 is a simulation result of the control device of the array antenna device of FIG. 1, which shows a desired wave direction φ = 30 ° and an evaluation function | E^V|-| E^H6 is a graph showing a directional characteristic pattern in a horizontal plane when a convergent reactance value when | is set in the array antenna device 100.
FIG. 32 is a simulation result of the control device of the array antenna device of FIG. 1, where a desired wave direction φ = 30 °, and an evaluation function | E^H|-| E^V6 is a graph showing a directional characteristic pattern in a horizontal plane when a convergent reactance value when | is set in the array antenna device 100.
FIG. 33 shows simulation results of the control device of the array antenna device of FIG. 1, in which a desired wave direction φ = 30 ° and an evaluation function | E^V+ JE^H6 is a graph showing a directional characteristic pattern in a horizontal plane when a convergent reactance value when | is set in the array antenna device 100.
FIG. 34 is a simulation result of the control device of the array antenna device of FIG. 1, where a desired wave direction φ = 30 °, and an evaluation function | E^V−jE^H6 is a graph showing a directional characteristic pattern in a horizontal plane when a convergent reactance value when | is set in the array antenna device 100.
FIG. 35 is a simulation result of the control device of the array antenna device of FIG. 1, where a desired wave direction φ = 30 °, and an evaluation function | E^V| + | E^H6 is a graph showing a directional characteristic pattern in a horizontal plane when a convergent reactance value when | is set in the array antenna device 100.
FIG. 36 is a diagram illustrating a polarization component of a radio signal arriving at an array antenna device 150 according to the related art.
[Explanation of symbols]
A0: Exciting element,
A1 to A6, A11 to A16, A21 to A26, A38 to A43, A51 to A56...
1. Low noise amplifier (LNA),
2. Down converter,
3. A / D converter,
4 demodulator,
5 ... coaxial cable,
6 ... Circulator,
7 ... wireless transmitter,
11 ground conductor
12-1 to 12-6, 12-11 to 12-16, 12-21 to 12-26, 12-38 to 12-43 ... variable reactance element,
20 ... Adaptive control type controller,
21: learning sequence signal generator
22 input device,
100, 110, 111, 120, 121, 122, 130, 140 ... array antenna device,
200, 210 ... circumference.

Claims (10)

An excitation element for transmitting and receiving a radio signal, at least one non-excitation element provided at a predetermined distance from the excitation element, and at least one variable reactance element respectively connected to the at least one non-excitation element By changing the reactance value of each of the variable reactance elements, an array antenna device that changes the directional characteristics by operating the at least one non-excitation element as a director or a reflector, respectively.
The at least one non-excitation element is formed of a dipole antenna and is provided so as to be inclined with respect to the excitation element, so that a radio signal of a horizontal polarization component in addition to a vertical polarization component parallel to the excitation element is provided. An array antenna device for transmitting and receiving data. 2. The array antenna device according to claim 1, wherein a vertical polarization component and a horizontal polarization component of a radio signal to be transmitted and received are controlled by changing a reactance value of the variable reactance element. A first non-excitation element inclined at a predetermined positive angle with respect to the excitation element, and a second non-excitation element inclined at a predetermined negative angle with respect to the excitation element in a direction opposite to the angle; And a reactance value of a variable reactance element connected to the first parasitic element and a reactance value of a variable reactance element connected to the second parasitic element. 3. The array antenna device according to claim 2, wherein at least one of the first parasitic element and the second parasitic element is operated by changing the following. A reactance value such that the integrated value of the current on one of the first and second parasitic elements becomes substantially zero is set in the variable reactance element connected to the parasitic element. 4. The method according to claim 3, wherein the vector effective length of the antenna element is set to substantially zero, and the antenna element is electrically removed to selectively operate only the other parasitic element. An array antenna device as described in the above. 5. The array antenna device according to claim 3, wherein the first parasitic element and the second parasitic element in each set of the parasitic elements are provided at substantially the same position. 5. The array antenna device according to claim 3, wherein the first parasitic element and the second parasitic element in each of the parasitic element sets are provided at a predetermined distance from each other. The array antenna device according to any one of claims 1 to 6, further comprising at least one third non-excitation element provided so as to be orthogonal to the excitation element. Instead of the plurality of non-excitation elements provided at a predetermined distance from the excitation element, a plurality of non-excitation elements are provided so that the excitation element and the plurality of non-excitation elements are arranged in a straight line. The array antenna device according to any one of claims 1 to 7, wherein: A method for controlling an array antenna device according to any one of claims 1 to 8, wherein a repetitive numerical solution in a nonlinear programming method is used based on a reception signal received by the excitation element. The reactance of the variable reactance element for directing the main beam of the array antenna in the direction of the desired wave and nulling in the direction of the interference wave so that the value of the predetermined evaluation function including the received signal is maximum or minimum. A method for controlling an array antenna device, comprising calculating and setting a value. The control device for an array antenna device according to any one of claims 1 to 8, wherein the control device uses an iterative numerical solution in a nonlinear programming method based on a received signal received by the excitation element. A reactance of a variable reactance element for directing a main beam of the array antenna in a direction of a desired wave and directing null in a direction of an interference wave so that a value of a predetermined evaluation function including the received signal is maximum or minimum. A control device for an array antenna device, comprising control means for calculating and setting a value.

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