JP3660181B2

JP3660181B2 - Antenna measuring apparatus and antenna measuring method

Info

Publication number: JP3660181B2
Application number: JP33839799A
Authority: JP
Inventors: 博之出口; 勇千葉
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 1999-11-29
Filing date: 1999-11-29
Publication date: 2005-06-15
Anticipated expiration: 2019-11-29
Also published as: JP2001153906A

Description

【０００１】
【発明の属する技術分野】
この発明は、アンテナの放射特性と開口面分布を測定して評価するアンテナ測定装置及びアンテナ測定方法に関するものであり、特に、平面アレーアンテナ及び平面レドームアンテナの近傍電界、ミリ波サブミリ波反射鏡アンテナの鏡面誤差を短時間で精度良く評価するアンテナ測定装置及びアンテナ測定方法に関するものである。
【０００２】
【従来の技術】
図１１は例えば「測定距離の変化により反射波を除去する遠方界放射パターン測定法」電子情報通信学会論文誌（Ｂ−ＩＩ），Ｖｏｌ．Ｊ８０−Ｂ−ＩＩ，Ｎｏ．３，ｐｐ．２４８−２５６，１９９７年３月発行に示された従来のアンテナ測定装置を示す構成図であり、図において、１は送信機、２は送信機１に接続された供試アンテナ、３は受信機４に接続された測定用プローブ、４は受信機、５は測定用プローブ３を２次元で走査する平面スキャナ、６は平面スキャナ５の走査を制御するスキャナ制御装置、７は測定用プローブ３により受信された電界を蓄積して可視化するパターン表示器、８は供試アンテナ２を駆動して、供試アンテナ２と測定用プローブ３間の距離を変化させる測定距離可変機構、９は測定距離可変機構８を制御して供試アンテナ２の駆動／静止を繰り返す測定距離制御器、１０は測定距離を変化させて受信された電界を測定距離に関してフーリエ変換を施すパターン演算処理器である。
【０００３】
次に動作について説明する。
送信機１から送信された電波は供試アンテナ２から放射される。この空間に放射された電波は、測定用プローブ３で受信され、受信機４に受信信号として取り出される。
【０００４】
この受信信号には種々の測定誤差が含まれている。その理由は、供試アンテナ２以外に何も存在しない測定環境において、供試アンテナ２から放射された電波が測定用プローブ３により受信されたときの受信信号が本来の測定量となるが、実際の測定環境を見ると、送信機１，受信機４及び平面スキャナ５が散乱体として存在し、さらに屋内測定では建物による影響、屋外測定では周囲環境の影響によって電波が散乱するので、その受信信号には種々の測定誤差が含まれる。
【０００５】
そこで、この従来装置（以下、従来装置１という）では、その測定誤差を除去するために、測定距離可変機構８及び測定距離制御器９を用いて、供試アンテナ２と測定用プローブ３間の距離を変化させるとともに、パターン演算処理器１０が受信電界を測定距離に関してフーリエ変換して、その得られたスペクトラムの成分から距離に依存しない成分を取り出し、測定誤差を除去した測定値を推定するようにする。また、その他のスペクトラム成分からは周囲反射波の波源推定、即ち、測定誤差の評価が行われる。
なお、測定距離を変化させる理由は、周囲環境を変化させて測定誤差成分の振幅，位相を変化させるためである。従って、異なる条件下で電界を複数回測定することにより、測定精度の向上が図られている。
【０００６】
図１２は従来装置１と異なる従来装置（以下、従来装置２という）を示す構成図であり、図において、図１１と同一符号は同一または相当部分を示すので説明を省略する。
１１は測定用プローブ３により受信された電界の振幅成分のみを受信信号として取り出す電力受信機、１２は測定距離をｚ＝ｚ１，ｚ２としたときの電力測定値から繰返し演算によって位相パターンを復元する位相パターン復元器である。なお、従来装置２は、“Ｆａｒ−ｆｉｅｌｄｐａｔｔｅｒｎｄｅｔｅｒｍｉｎａｔｉｏｎｆｒｏｍｔｈｅｎｅａｒ−ｆｉｅｌｄａｍｐｌｉｔｕｄｅｏｎｔｗｏｓｕｒｆａｃｅ，”ＩＥＥＥＴｒａｎｓ．，ＡｎｔｅｎｎａｓＰｒｏｐａｇａｔ．，ｖｏｌ．ＡＰ−３８，Ｎｏ．１１，ｐｐ．１７７２−１７７９，Ｎｏｖ．１９９０に示されている。
【０００７】
次に動作について説明する。
送信機１から送信された電波は供試アンテナ２から放射される。この空間に放射された電波は、測定用プローブ３で受信され、電力受信機１１に受信信号として取り出される。
【０００８】
ただし、この受信信号には電界の振幅のみで位相は含まれない。位相を測定しない理由は、ミリ波やサブミリ波における測定では、位相変動が大きいため誤差が大きく、電力のみの測定が容易であるためである。
しかしながら、遠方放射パターンをフィールド変換によって求めるためには、近傍電界の振幅だけでなく、位相も必要となる。そのため、測定距離可変機構８及び測定距離制御器９によって、測定距離の異なるｚ＝ｚ１，ｚ２で２次元電界の振幅分布が測定され、位相パターン復元器１２により位相パターンが推定される。
【０００９】
測定値と推定した位相パターンとにより、遠方放射パターンが得られる。平面上の２次元分布を測定する平面スキャナ５を用いた場合、平面波展開法によって近傍電界から遠方放射パターンが求められる。
図１３を参照しながら、測定距離による位相パターン復元器１２の動作原理について説明する。
【００１０】
まず、ｚ＝ｚ１において振幅測定値を得て（ステップＳＴ１）、位相分布の初期値を計算によって仮定し、ｚ＝ｚ１における２次元電界分布を仮定する（ステップＳＴ２）。
このｚ＝ｚ１の位置での２次元電界分布から、平面波展開法によってｚ＝ｚ２の位置での２次元電界分布を計算し、ｚ＝ｚ２での位相分布を求める（ステップＳＴ３）。
【００１１】
また、ｚ＝ｚ２の位置での振幅分布としては測定値を用い（ステップＳＴ４）、ｚ＝ｚ２での２次元電界分布が仮定される（ステップＳＴ５）。
このｚ＝ｚ２の位置での２次元電界分布から、平面波展開法によってｚ＝ｚ１の位置での２次元電界分布を計算し、ｚ＝ｚ１の位置での位相分布を求める（ステップＳＴ６）。
【００１２】
この位相分布と初期値として仮定した位相分布の差を求める。上述した演算処理を繰り返すことによって、この位相分布の差を充分小さくし、そのときの位相分布を推定値とする（ステップＳＴ７〜ＳＴ９）。この位相分布推定値と振幅分布測定値から２次元電界分布が得られるので、平面波展開法によって遠方放射パターンを求めることができる。異なる条件下で電界の振幅を２回測定することにより位相が復元される。言い換えると、ミリ波やサブミリ波で生じる位相変動による誤差が除去され、測定精度の向上が図られる。
【００１３】
【発明が解決しようとする課題】
従来のアンテナ測定装置は以上のように構成されているので、従来装置１の場合、測定距離の異なる条件下で、電界を多数測定しなければならない。近傍界測定のように、２次元電界分布の測定が必要な場合、多数の２次元電界分布を測定しなければならないので、測定に長い時間を要する課題があった。
従来装置２の場合、測定距離の異なる条件下で電界の振幅を２次元で２回測定しなければならないので、この場合も測定時間が長くなる課題があった。
また、従来装置１，２では、測定距離を可変にする装置が必要で、測定距離を可変させるときの駆動精度は、測定波長に応じて高い精度が必要となる。従って、ミリ波やサブミリ波では極めて高精度な駆動装置が必要となり、製造コストが高くなる課題があった。
【００１４】
この発明は上記のような課題を解決するためになされたもので、測定距離を可変する駆動装置を設けることなく、短時間に高精度な測定を行うことができるアンテナ測定装置及びアンテナ測定方法を得ることを目的とする。
【００１５】
【課題を解決するための手段】
この発明に係るアンテナ測定装置は、測定手段により測定された２次元電界の振幅分布及び位相分布を供試アンテナの開口面位置にフィールド変換する第１のフィールド変換手段と、その第１のフィールド変換手段によりフィールド変換された２次元電界の振幅分布及び位相分布を不要波の仮想的な波源位置にフィールド変換して、その２次元電界の振幅分布及び位相分布に含まれる不要波成分を計算し、その不要波成分を供試アンテナの開口面位置にフィールド変換する第２のフィールド変換手段とを設け、その第１のフィールド変換手段によりフィールド変換された２次元電界の振幅分布及び位相分布から第２のフィールド変換手段によりフィールド変換された不要波成分を除去するようにしたものである。
【００１６】
この発明に係るアンテナ測定装置は、測定手段により測定された２次元電界の振幅分布を供試アンテナの開口面位置にフィールド変換して、その開口面における外側領域の振幅分布を零に置き換える振幅分布置換手段と、その置換後の２次元電界の振幅分布を測定手段におけるプローブの測定面位置にフィールド変換して、その測定面における位相分布を推定する位相推定手段とを設けたものである。
【００１７】
この発明に係るアンテナ測定装置は、測定手段により測定された２次元放射電界の振幅分布及び位相分布を供試アンテナの開口面位置にフィールド変換して、その開口面における外側領域の振幅分布及び位相分布を零に置き換える電界置換手段と、その置換後の２次元放射電界の振幅分布及び位相分布を測定用プローブの測定面位置にフィールド変換して、その測定用プローブにおける測定角度範囲の外側領域の振幅分布及び位相分布を推定する電界推定手段とを設けたものである。
【００１８】
この発明に係るアンテナ測定装置は、測定手段により測定された２次元放射電界の振幅分布を供試アンテナの開口面位置にフィールド変換して、その開口面における外側領域の振幅分布を零に置き換える振幅分布置換手段と、その置換後の２次元放射電界の振幅分布を測定用プローブの測定面位置にフィールド変換して、その測定面における位相分布を推定する位相推定手段とを設けたものである。
【００１９】
この発明に係るアンテナ測定方法は、２次元電界の振幅分布及び位相分布を供試アンテナの開口面位置にフィールド変換する一方、その２次元電界の振幅分布及び位相分布を不要波の仮想的な波源位置にフィールド変換して、その２次元電界の振幅分布及び位相分布に含まれる不要波成分を計算するとともに、その不要波成分を供試アンテナの開口面位置にフィールド変換し、供試アンテナの開口面位置にある２次元電界の振幅分布及び位相分布から上記不要波成分を除去するようにしたものである。
【００２０】
この発明に係るアンテナ測定方法は、２次元電界の振幅分布を供試アンテナの開口面位置にフィールド変換して、その開口面における外側領域の振幅分布を零に置き換え、その置換後の２次元電界の振幅分布を測定用プローブの測定面位置にフィールド変換して、その測定面における位相分布を推定するようにしたものである。
【００２１】
この発明に係るアンテナ測定方法は、２次元放射電界の振幅分布及び位相分布を供試アンテナの開口面位置にフィールド変換して、その開口面における外側領域の振幅分布及び位相分布を零に置き換え、その置換後の２次元放射電界の振幅分布及び位相分布を測定用プローブの測定面位置にフィールド変換して、その測定用プローブにおける測定角度範囲の外側領域の振幅分布及び位相分布を推定するようにしたものである。
【００２２】
この発明に係るアンテナ測定方法は、２次元放射電界の振幅分布を供試アンテナの開口面位置にフィールド変換して、その開口面における外側領域の振幅分布を零に置き換え、その置換後の２次元放射電界の振幅分布を測定用プローブの測定面位置にフィールド変換して、その測定面における位相分布を推定するようにしたものである。
【００２３】
【発明の実施の形態】
以下、この発明の実施の一形態を説明する。
実施の形態１．
図１はこの発明の実施の形態１によるアンテナ測定装置を示す構成図であり、図において、２１は電波を供試アンテナ２２に送信する送信機、２２は送信機２１に接続され、送信機２１から送信された電波を空間に放射する供試アンテナ、２３は供試アンテナ２２の近傍位置における２次元電界の振幅分布及び位相分布を測定する測定用プローブ、２４は測定用プローブ２３により測定された２次元電界の振幅分布及び位相分布を受信信号として取り込む受信機である。
なお、測定用プローブ２３及び受信機２４から測定手段が構成される。
【００２４】
２５は測定用プローブ２３を２次元で走査する平面スキャナ、２６は平面スキャナ２５の走査を制御するスキャナ制御器、２７は２次元電界を蓄積して可視化するパターン表示器、２８は２次元電界の振幅分布及び位相分布を不要波の仮想的な波源位置にフィールド変換して、その２次元電界の振幅分布及び位相分布に含まれる不要波成分を計算し、その２次元電界の振幅分布及び位相分布から不要波成分を除去する不要波除去演算処理器（第１及び第２のフィールド変換手段、不要波除去手段）、２９は平面スキャナ２５のｘ方向の走査、３０は平面スキャナ２５のｙ方向の走査である。
図２はこの発明の実施の形態１によるアンテナ測定方法を示すフローチャートである。
【００２５】
次に動作について説明する。
送信機２１から送信された電波は供試アンテナ２２から放射される。この空間に放射された電波は、測定用プローブ２３で受信され、受信機２４に受信信号として取り出される。
【００２６】
即ち、測定用プローブ２３の平面スキャナ２５によるｘ方向の走査２９，ｙ方向の走査３０によって２次元電界分布が受信される（ステップＳＴ１１）。
以下、図３を参照しながら、不要波除去演算処理器２８が受信信号から不要波成分を除去する原理について説明する。
【００２７】
まず、不要波除去演算処理器２８は、測定用プローブ２３の測定面をｚ＝ｚｍとすると、平面波展開法によって、２次元電界分布（２次元電界の振幅分布及び位相分布）の測定値を供試アンテナ２２の開口面を含む面上の位置（ｚ＝０）にフィールド変換することにより、供試アンテナ２２の開口面における２次元電界分布を求める（ステップＳＴ１２）。
【００２８】
そして、不要波除去演算処理器２８は、供試アンテナ２２における開口面の外側の電界（振幅、位相）を０に変えて、その開口面の内側の電界分布を求める（ステップＳＴ１３）。
一方、受信信号に含まれる不要波成分を求めるため、供試アンテナ２２における開口面の内側の電界（振幅、位相）を０に変えて、平面波展開法によってｚの負方向である不要波の波源位置（ｚ＝ｚｉ）にフィールド変換する（ステップＳＴ１４）。
ここで、不要波の波源位置は、ビームウエストによって推定できるので、ｚ＝ｚｉはビームウエスト位置に取ることにする。この部分には実際には、波源はないが、仮想的に不要波の波源があると考えられるので、不要波のイメージと呼ぶことにする。
【００２９】
不要波除去演算処理器２８は、ｚ＝ｚｉの位置にフィールド変換した２次元電界分布において、この不要波のイメージである電界（振幅、位相）を０にして、ｚ＝ｚｉの位置での２次元電界分布から再度ｚ＝０の位置にフィールド変換し、供試アンテナ２２における開口面の外側の電界分布を推定する（ステップＳＴ１５）。
【００３０】
そして、不要波除去演算処理器２８は、供試アンテナ２２における開口面の外側の電界分布推定値と、先に求めた供試アンテナ２２における開口面の内側の電界分布とを合成して、不要波成分が除去された供試アンテナ２２の開口面の２次元電界分布を求める（ステップＳＴ１６）。
これにより、供試アンテナ２２と測定用プローブ２３間の距離を変化させることなく、平面波展開法によってフィールド変換することにより、更に遠方放射パターンを得ることができる。
【００３１】
図４は実際に測定して得られた結果を示し、同図（ａ）は電波暗室での近傍界測定から直接フィールド変換して求めた不要波を含む水平面内及び垂直面内の遠方放射パターンであり、同図（ｂ）はこの実施の形態１により電波暗室での測定を実際に行い、フィールド変換して得られる水平面内及び垂直面内の遠方放射パターンを示すものである。
【００３２】
比較のため、測定環境の良好な屋外を選んで、直接遠方界測定した水平面内遠方放射パターンを点線で示す。同図（ａ）では不要波の影響によって主ビームの形が大きく変化しているのに対し、同図（ｂ）では主ビームが点線と良く一致しており、不要波が除去されていることが分かる。
【００３３】
以上で明らかなように、この実施の形態１によれば、２次元電界の振幅分布及び位相分布を不要波の仮想的な波源位置にフィールド変換して、その２次元電界の振幅分布及び位相分布に含まれる不要波成分を計算し、その２次元電界の振幅分布及び位相分布から不要波成分を除去するように構成したので、測定距離を可変する駆動装置を設けることなく、短時間に高精度な測定を行うことができる効果を奏する。
【００３４】
実施の形態２．
図５はこの発明の実施の形態２によるアンテナ測定装置を示す構成図であり、図において、図１と同一符号は同一または相当部分を示すので説明を省略する。３１は測定用プローブ２３により測定された２次元電界の振幅分布を受信信号として取り込む電力受信機（測定手段）、３２は電力受信機３１が出力する２次元電界の振幅分布を供試アンテナ２２の開口面位置にフィールド変換して、その開口面における外側領域の振幅分布を零に置き換えるとともに、その置換後の２次元電界の振幅分布を測定用プローブ２３の測定面位置にフィールド変換して、その測定面における位相分布を推定する近傍位相パターン復元器（振幅分布置換手段、位相推定手段）である。
図６はこの発明の実施の形態２によるアンテナ測定方法を示すフローチャートである。
【００３５】
次に動作について説明する。
送信機２１から送信された電波は供試アンテナ２２から放射される。この空間に放射された電波は、測定用プローブ２３で受信され、電力受信機３１に受信電界分布の電力（振幅分布）のみが信号として取り出される。
【００３６】
以下、近傍位相パターン復元器３２が近傍界の位相パターンを推定する原理について説明する。
まず、近傍位相パターン復元器３２は、ｚ＝ｚ１において振幅測定値を得ると（ステップＳＴ２１）、位相分布の初期値を計算によって仮定し、ｚ＝ｚ１における２次元電界分布（振幅分布）を仮定する。
【００３７】
そして、近傍位相パターン復元器３２は、ｚ＝ｚ１の位置での２次元電界分布から、平面波展開法によって供試アンテナ２２の開口面を含むｚ＝０の位置での２次元電界分布を計算する（ステップＳＴ２２）。
近傍位相パターン復元器３２は、供試アンテナ２２における開口面の外側領域の電界（振幅）を０に変えて（ステップＳＴ２３）、平面波展開法によってｚ＝ｚ１の位置にフィールド変換して、ｚ＝ｚ１の位置での２次元電界分布を計算し、ｚ＝ｚ１の位置での位相分布を求める（ステップＳＴ２４）。
【００３８】
この位相分布と初期値として仮定した位相分布の差を求める。上述した演算処理を繰り返すことによって、上記位相分布の差を充分小さくし、収束した位相分布を推定値とする（ステップＳＴ２５〜ＳＴ２７）。この位相分布推定値と振幅分布測定値からｚ＝ｚ１の２次元電界分布が得られるので、平面波展開法によって遠方放射パターンを求めることができる。
これにより、ミリ波やサブミリ波で生じる位相変動による誤差が除去され、測定精度を向上させることができる。
【００３９】
以上で明らかなように、この実施の形態２によれば、２次元電界の振幅分布を供試アンテナ２２の開口面位置にフィールド変換して、その開口面における外側領域の振幅分布を零に置き換え、その置換後の２次元電界の振幅分布を測定用プローブ２３の測定面位置にフィールド変換して、その測定面における位相分布を推定するように構成したので、測定距離を可変する駆動装置を設けることなく、測定用プローブ２３の測定面における位相分布を推定することができるようになり、その結果、短時間に高精度な測定を行うことができる効果を奏する。
【００４０】
実施の形態３．
図７はこの発明の実施の形態３によるアンテナ測定装置を示す構成図であり、図において、図１と同一符号は同一または相当部分を示すので説明を省略する。４１は供試アンテナ２２を搭載し、２軸で姿勢を変える回転台、４２は回転台４１の駆動を制御する回転台制御器、４３は回転台４１の仰角走査、４４は回転台４１の方位角走査、４５は受信機２４が出力する２次元放射電界の振幅分布及び位相分布を供試アンテナ２２の開口面位置にフィールド変換して、その開口面における外側領域の振幅分布及び位相分布を零に置き換えるとともに、その置換後の２次元放射電界の振幅分布及び位相分布を測定用プローブ２３の測定面位置にフィールド変換して、その測定用プローブ２３における測定角度範囲の外側領域の振幅分布及び位相分布を推定する分解能復元器（電界置換手段、電界推定手段）である。
【００４１】
次に動作について説明する。
送信機２１から送信された電波は測定用プローブ２３から放射される。この空間に放射された電波は、供試アンテナ２２で受信され、受信機２４に受信信号として取り出される。
【００４２】
回転台４１を仰角走査４３及び方位角走査４４により２軸でもって姿勢変化させることにより、供試アンテナ２２の２次元放射電界分布（振幅分布及び位相分布）が測定される。その測定角度範囲は周囲反射の影響及び測定時間を考慮して有限に取られる。
【００４３】
分解能復元器４５は、２次元放射電界分布の測定値から測定範囲の外側の角度範囲の放射電界を推定し、空間分解能を向上させた開口面分布を取得する。
以下、図８を参照しながら、分解能復元器４５によって開口面上の分解能を向上させる原理について説明する。
【００４４】
まず、分解能復元器４５は、距離Ｒ＝Ｒｍにおける球面上で２次元放射電界分布（振幅分布及び位相分布）を測定する。測定角度範囲の外側領域の放射電界としては初期値０を仮定する。この測定角度範囲より広い角度範囲の２次元放射電界分布（初期値含）を平面波展開法によって、供試アンテナ２２の開口面位置にフィールド変換して、供試アンテナ２２の開口面を含む面内ｚ＝０の開口面電界分布を求める。
【００４５】
そして、分解能復元器４５は、供試アンテナ２２における開口面の外側領域の電界を０に変えて、再度、平面波展開法によってフィールド変換し、Ｒ＝Ｒｍの球面上の放射電界分布を求め、測定角度範囲の外側の放射電界分布を推定する。
分解能復元器４５は、この推定した放射電界分布と、測定した放射電界分布を合成し、測定角度範囲の外側の推定した放射電界分布が収束するまで、同図の太い矢印で示した演算処理を繰返す。広角の電界分布はこのような推定値により周囲反射の影響を受けないので、これを基に高い分解能の開口面分布をより正確に求めることができる。
【００４６】
以上で明らかなように、この実施の形態３によれば、２次元放射電界の振幅分布及び位相分布を供試アンテナ２２の開口面位置にフィールド変換して、その開口面における外側領域の振幅分布及び位相分布を零に置き換え、その置換後の２次元放射電界の振幅分布及び位相分布を測定用プローブ２３の測定面位置にフィールド変換して、その測定用プローブ２３における測定角度範囲の外側領域の振幅分布及び位相分布を推定するように構成したので、測定距離を可変する駆動装置を設けることなく、短時間に高精度な測定を行うことができる効果を奏する。
【００４７】
実施の形態４．
図９はこの発明の実施の形態４によるアンテナ測定装置を示す構成図であり、図において、図７と同一符号は同一または相当部分を示すので説明を省略する。
４６は電力受信機３１が出力する２次元放射電界の振幅分布を供試アンテナ２２の開口面位置にフィールド変換して、その開口面における外側領域の振幅分布を零に置き換えるとともに、その置換後の２次元放射電界の振幅分布を測定用プローブ２３の測定面位置にフィールド変換して、その測定面における位相分布を推定する遠方位相パターン復元器（振幅分布置換手段、位相推定手段）である。
図１０はこの発明の実施の形態４によるアンテナ測定方法を示すフローチャートである。
【００４８】
次に動作について説明する。
送信機２１から送信された電波は測定用プローブ２３から放射される。この空間に放射された電波は、供試アンテナ２２で受信され、電力受信機３１に受信電界の電力（振幅分布）のみが信号として取り出される。
回転台４１を仰角走査４３及び方位角走査４４により２軸でもって姿勢変化させることによって、供試アンテナ２２の２次元電界振幅放射パターンが測定される。
【００４９】
以下、遠方位相パターン復元器４６が遠方界の位相パターンを推定する原理について説明する。
まず、遠方位相パターン復元器４６は、Ｒ＝Ｒ１において振幅測定値を得ると（ステップＳＴ３１）、位相分布の初期値を計算によって仮定し、Ｒ＝Ｒ１における２次元放射電界分布を仮定する。
【００５０】
そして、遠方位相パターン復元器４６は、Ｒ＝Ｒ１の位置での２次元放射電界分布から、平面波展開法によって供試アンテナ２２の開口面を含むｚ＝０の位置での２次元放射電界分布を計算する（ステップＳＴ３２）。
遠方位相パターン復元器４６は、供試アンテナ２２における開口面の外側領域の電界（振幅）を０に変えて（ステップＳＴ３３）、平面波展開法によってＲ＝Ｒ１の位置にフィールド変換して、Ｒ＝Ｒ１の位置での２次元放射電界分布を計算し、Ｒ＝Ｒ１の位置での位相分布を求める（ステップＳＴ３４）。
【００５１】
この位相分布と初期値として仮定した位相分布の差を求める。上述した演算処理を繰り返すことによって、上記位相分布の差を充分小さくし、収束した位相分布を推定値とする（ステップＳＴ３５〜ＳＴ３７）。この位相分布推定値と振幅分布測定値からＲ＝Ｒ１の２次元電界分布が得られるので、平面波展開法によって開口面電界分布を求めることができる。
これにより、ミリ波やサブミリ波で生じる位相変動による誤差が除去され、測定精度を向上させることができる。
【００５２】
以上で明らかなように、この実施の形態４によれば、２次元放射電界の振幅分布を供試アンテナ２２の開口面位置にフィールド変換して、その開口面における外側領域の振幅分布を零に置き換え、その置換後の２次元放射電界の振幅分布を測定用プローブ２３の測定面位置にフィールド変換して、その測定面における位相分布を推定するように構成したので、測定距離を可変する駆動装置を設けることなく、測定用プローブ２３の測定面における位相分布を推定することができるようになり、その結果、短時間に高精度な測定を行うことができる効果を奏する。
【００５３】
【発明の効果】
以上のように、この発明によれば、測定手段により測定された２次元電界の振幅分布及び位相分布を供試アンテナの開口面位置にフィールド変換する第１のフィールド変換手段と、その第１のフィールド変換手段によりフィールド変換された２次元電界の振幅分布及び位相分布を不要波の仮想的な波源位置にフィールド変換して、その２次元電界の振幅分布及び位相分布に含まれる不要波成分を計算し、その不要波成分を供試アンテナの開口面位置にフィールド変換する第２のフィールド変換手段とを設け、その第１のフィールド変換手段によりフィールド変換された２次元電界の振幅分布及び位相分布から第２のフィールド変換手段によりフィールド変換された不要波成分を除去するように構成したので、測定距離を可変する駆動装置を設けることなく、短時間に高精度な測定を行うことができる効果がある。
【００５４】
この発明によれば、測定手段により測定された２次元電界の振幅分布を供試アンテナの開口面位置にフィールド変換して、その開口面における外側領域の振幅分布を零に置き換える振幅分布置換手段と、その置換後の２次元電界の振幅分布を測定手段におけるプローブの測定面位置にフィールド変換して、その測定面における位相分布を推定する位相推定手段とを設けるように構成したので、測定距離を可変する駆動装置を設けることなく、測定用プローブの測定面における位相分布を推定することができるようになり、その結果、短時間に高精度な測定を行うことができる効果がある。
【００５５】
この発明によれば、測定手段により測定された２次元放射電界の振幅分布及び位相分布を供試アンテナの開口面位置にフィールド変換して、その開口面における外側領域の振幅分布及び位相分布を零に置き換える電界置換手段と、その置換後の２次元放射電界の振幅分布及び位相分布を測定用プローブの測定面位置にフィールド変換して、その測定用プローブにおける測定角度範囲の外側領域の振幅分布及び位相分布を推定する電界推定手段とを設けるように構成したので、測定距離を可変する駆動装置を設けることなく、短時間に高精度な測定を行うことができる効果がある。
【００５６】
この発明によれば、測定手段により測定された２次元放射電界の振幅分布を供試アンテナの開口面位置にフィールド変換して、その開口面における外側領域の振幅分布を零に置き換える振幅分布置換手段と、その置換後の２次元放射電界の振幅分布を測定用プローブの測定面位置にフィールド変換して、その測定面における位相分布を推定する位相推定手段とを設けるように構成したので、測定距離を可変する駆動装置を設けることなく、測定用プローブの測定面における位相分布を推定することができるようになり、その結果、短時間に高精度な測定を行うことができる効果がある。
【００５７】
この発明によれば、２次元電界の振幅分布及び位相分布を供試アンテナの開口面位置にフィールド変換する一方、その２次元電界の振幅分布及び位相分布を不要波の仮想的な波源位置にフィールド変換して、その２次元電界の振幅分布及び位相分布に含まれる不要波成分を計算するとともに、その不要波成分を供試アンテナの開口面位置にフィールド変換し、供試アンテナの開口面位置にある２次元電界の振幅分布及び位相分布から上記不要波成分を除去するように構成したので、測定距離を可変する駆動装置を設けることなく、短時間に高精度な測定を行うことができる効果がある。
【００５８】
この発明によれば、２次元電界の振幅分布を供試アンテナの開口面位置にフィールド変換して、その開口面における外側領域の振幅分布を零に置き換え、その置換後の２次元電界の振幅分布を測定用プローブの測定面位置にフィールド変換して、その測定面における位相分布を推定するように構成したので、測定距離を可変する駆動装置を設けることなく、測定用プローブの測定面における位相分布を推定することができるようになり、その結果、短時間に高精度な測定を行うことができる効果がある。
【００５９】
この発明によれば、２次元放射電界の振幅分布及び位相分布を供試アンテナの開口面位置にフィールド変換して、その開口面における外側領域の振幅分布及び位相分布を零に置き換え、その置換後の２次元放射電界の振幅分布及び位相分布を測定用プローブの測定面位置にフィールド変換して、その測定用プローブにおける測定角度範囲の外側領域の振幅分布及び位相分布を推定するように構成したので、測定距離を可変する駆動装置を設けることなく、短時間に高精度な測定を行うことができる効果がある。
【００６０】
この発明によれば、２次元放射電界の振幅分布を供試アンテナの開口面位置にフィールド変換して、その開口面における外側領域の振幅分布を零に置き換え、その置換後の２次元放射電界の振幅分布を測定用プローブの測定面位置にフィールド変換して、その測定面における位相分布を推定するように構成したので、測定距離を可変する駆動装置を設けることなく、測定用プローブの測定面における位相分布を推定することができるようになり、その結果、短時間に高精度な測定を行うことができる効果がある。
【図面の簡単な説明】
【図１】この発明の実施の形態１によるアンテナ測定装置を示す構成図である。
【図２】この発明の実施の形態１によるアンテナ測定方法を示すフローチャートである。
【図３】不要波除去演算処理器の動作原理を示す説明図である。
【図４】水平面内及び垂直面内の遠方放射パターンを示すグラフ図である。
【図５】この発明の実施の形態２によるアンテナ測定装置を示す構成図である。
【図６】この発明の実施の形態２によるアンテナ測定方法を示すフローチャートである。
【図７】この発明の実施の形態３によるアンテナ測定装置を示す構成図である。
【図８】分解能復元器の動作原理を示す説明図である。
【図９】この発明の実施の形態４によるアンテナ測定装置を示す構成図である。
【図１０】この発明の実施の形態４によるアンテナ測定方法を示すフローチャートである。
【図１１】従来のアンテナ測定装置を示す構成図である。
【図１２】従来のアンテナ測定装置を示す構成図である。
【図１３】従来のアンテナ測定装置の動作を示すフローチャートである。
【符号の説明】
２１送信機、２２供試アンテナ、２３測定用プローブ（測定手段）、２４受信機（測定手段）、２５平面スキャナ、２６スキャナ制御器、２７パターン表示器、２８不要波除去演算処理器（第１及び第２のフィールド変換手段、不要波除去手段）、２９平面スキャナ２５のｘ方向の走査、３０平面スキャナ２５のｙ方向の走査、３１電力受信機（測定手段）、３２近傍位相パターン復元器（振幅分布置換手段、位相推定手段）、４１回転台、４２回転台制御器、４３回転台４１の仰角走査、４４回転台４１の方位角走査、４５分解能復元器（電界置換手段、電界推定手段）、４６遠方位相パターン復元器（振幅分布置換手段、位相推定手段）。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an antenna measuring device and an antenna measuring method for measuring and evaluating the radiation characteristics and aperture distribution of an antenna, and in particular, a near-field electric field of a planar array antenna and a planar radome antenna, a millimeter wave submillimeter wave reflector antenna The present invention relates to an antenna measuring apparatus and an antenna measuring method for accurately evaluating a mirror surface error in a short time.
[0002]
[Prior art]
FIG. 11 shows, for example, “Far-field radiation pattern measurement method for removing reflected wave by changing measurement distance”, IEICE Transactions (B-II), Vol. J80-B-II, No. 3, pp. 248-256, is a block diagram showing a conventional antenna measuring apparatus disclosed in March 1997, in which 1 is a transmitter, 2 is a test antenna connected to the transmitter 1, 3 is a receiver The measurement probe connected to 4, 4 is a receiver, 5 is a planar scanner that scans the measurement probe 3 in two dimensions, 6 is a scanner control device that controls scanning of the planar scanner 5, and 7 is a measurement probe 3. A pattern indicator that accumulates and visualizes the received electric field, 8 is a measurement distance variable mechanism that drives the test antenna 2 to change the distance between the test antenna 2 and the measurement probe 3, and 9 is a variable measurement distance. A measurement distance controller 10 that repeats driving / resting of the antenna 2 under control of the mechanism 8 is a pattern arithmetic processing unit that performs Fourier transform on the measured distance by changing the measurement distance.
[0003]
Next, the operation will be described.
The radio wave transmitted from the transmitter 1 is radiated from the test antenna 2. The radio wave radiated to this space is received by the measurement probe 3 and taken out as a received signal by the receiver 4.
[0004]
This received signal includes various measurement errors. The reason is that in a measurement environment where nothing exists other than the test antenna 2, the received signal when the radio wave radiated from the test antenna 2 is received by the measurement probe 3 becomes the original measurement amount. In the measurement environment, the transmitter 1, the receiver 4 and the flat scanner 5 exist as scatterers. Furthermore, in indoor measurement, radio waves are scattered by the influence of the building and in the outdoor measurement by the influence of the surrounding environment. Includes various measurement errors.
[0005]
Therefore, in this conventional apparatus (hereinafter referred to as the conventional apparatus 1), in order to remove the measurement error, the measurement distance variable mechanism 8 and the measurement distance controller 9 are used to connect the test antenna 2 and the measurement probe 3 to each other. While changing the distance, the pattern arithmetic processing unit 10 performs Fourier transform on the measured electric field with respect to the measurement distance, extracts a component independent of the distance from the obtained spectrum component, and estimates the measurement value from which the measurement error is removed. To. Further, from the other spectrum components, the wave source estimation of the ambient reflected wave, that is, the measurement error is evaluated.
The reason for changing the measurement distance is to change the amplitude and phase of the measurement error component by changing the surrounding environment. Therefore, measurement accuracy is improved by measuring the electric field multiple times under different conditions.
[0006]
FIG. 12 is a block diagram showing a conventional apparatus (hereinafter referred to as conventional apparatus 2) different from the conventional apparatus 1. In the figure, the same reference numerals as those in FIG.
11 is a power receiver that extracts only the amplitude component of the electric field received by the measurement probe 3 as a received signal, and 12 is a phase pattern that is reconstructed by iterative calculation from the measured power value when the measurement distance is z = z1, z2. It is a phase pattern restorer. The conventional apparatus 2 is known as “Far-field pattern determination the near-field amplified on two surface,” IEEE Trans. , Antenna Propagate. , Vol. AP-38, no. 11, pp. 1772-1779, Nov. 1990.
[0007]
Next, the operation will be described.
The radio wave transmitted from the transmitter 1 is radiated from the test antenna 2. The radio wave radiated into this space is received by the measurement probe 3 and taken out as a received signal by the power receiver 11.
[0008]
However, this received signal includes only the amplitude of the electric field and does not include the phase. The reason for not measuring the phase is that the measurement in millimeter wave or submillimeter wave has a large error due to large phase fluctuation, and it is easy to measure only the power.
However, in order to obtain the far radiation pattern by field conversion, not only the amplitude of the near electric field but also the phase is required. Therefore, the measurement distance variable mechanism 8 and the measurement distance controller 9 measure the amplitude distribution of the two-dimensional electric field at different measurement distances z = z1 and z2, and the phase pattern restorer 12 estimates the phase pattern.
[0009]
A far radiation pattern is obtained from the measured value and the estimated phase pattern. When the planar scanner 5 that measures a two-dimensional distribution on a plane is used, a far radiation pattern is obtained from a near electric field by a plane wave expansion method.
With reference to FIG. 13, the operation principle of the phase pattern restorer 12 based on the measurement distance will be described.
[0010]
First, an amplitude measurement value is obtained at z = z1 (step ST1), an initial value of the phase distribution is assumed by calculation, and a two-dimensional electric field distribution at z = z1 is assumed (step ST2).
From the two-dimensional electric field distribution at the position of z = z1, the two-dimensional electric field distribution at the position of z = z2 is calculated by the plane wave expansion method to obtain the phase distribution at z = z2 (step ST3).
[0011]
Further, a measured value is used as the amplitude distribution at the position of z = z2 (step ST4), and a two-dimensional electric field distribution at z = z2 is assumed (step ST5).
From the two-dimensional electric field distribution at the position z = z2, the two-dimensional electric field distribution at the position z = z1 is calculated by the plane wave expansion method, and the phase distribution at the position z = z1 is obtained (step ST6).
[0012]
The difference between this phase distribution and the phase distribution assumed as an initial value is obtained. By repeating the arithmetic processing described above, the difference in phase distribution is made sufficiently small, and the phase distribution at that time is used as an estimated value (steps ST7 to ST9). Since a two-dimensional electric field distribution is obtained from the estimated phase distribution value and the measured amplitude distribution value, a far radiation pattern can be obtained by a plane wave expansion method. The phase is restored by measuring the amplitude of the electric field twice under different conditions. In other words, errors due to phase fluctuations caused by millimeter waves and submillimeter waves are eliminated, and measurement accuracy is improved.
[0013]
[Problems to be solved by the invention]
Since the conventional antenna measurement apparatus is configured as described above, in the case of the conventional apparatus 1, a large number of electric fields must be measured under different measurement distance conditions. When the measurement of the two-dimensional electric field distribution is necessary as in the near field measurement, a large number of two-dimensional electric field distributions must be measured.
In the case of the conventional apparatus 2, the amplitude of the electric field has to be measured twice in two dimensions under different measurement distances, and this also has a problem that the measurement time becomes long.
In addition, the conventional devices 1 and 2 require a device for changing the measurement distance, and the driving accuracy when changing the measurement distance requires high accuracy according to the measurement wavelength. Therefore, the millimeter wave and the submillimeter wave require a highly accurate drive device, and there is a problem that the manufacturing cost increases.
[0014]
The present invention has been made to solve the above-described problems, and provides an antenna measurement device and an antenna measurement method capable of performing high-precision measurement in a short time without providing a drive device that varies the measurement distance. The purpose is to obtain.
[0015]
[Means for Solving the Problems]
  The antenna measuring apparatus according to the present invention provides the amplitude distribution and phase distribution of the two-dimensional electric field measured by the measuring means.First field conversion means for field conversion to the aperture surface position of the antenna under test, and the amplitude distribution and phase distribution of the two-dimensional electric field field-converted by the first field conversion means as virtual wave source positions of unnecessary waves Second field conversion means for performing field conversion, calculating unnecessary wave components included in the amplitude distribution and phase distribution of the two-dimensional electric field, and field-converting the unnecessary wave components to the aperture position of the antenna under test is provided; The unnecessary wave component field-converted by the second field conversion means is removed from the amplitude distribution and phase distribution of the two-dimensional electric field field-converted by the first field conversion means.
[0016]
The antenna measuring apparatus according to the present invention field-converts the amplitude distribution of the two-dimensional electric field measured by the measuring means to the aperture position of the antenna under test, and replaces the amplitude distribution of the outer region on the aperture plane with zero. A replacement means and a phase estimation means for estimating the phase distribution on the measurement surface by field-converting the amplitude distribution of the two-dimensional electric field after the replacement into the measurement surface position of the probe in the measurement means are provided.
[0017]
The antenna measuring apparatus according to the present invention field-converts the amplitude distribution and phase distribution of the two-dimensional radiated electric field measured by the measuring means into the aperture position of the antenna under test, and the amplitude distribution and phase of the outer region on the aperture plane. Electric field replacement means for replacing the distribution with zero, and the amplitude distribution and phase distribution of the two-dimensional radiation electric field after the replacement are field-converted to the measurement surface position of the measurement probe, and the region outside the measurement angle range of the measurement probe And an electric field estimating means for estimating the amplitude distribution and the phase distribution.
[0018]
The antenna measuring apparatus according to the present invention field-converts the amplitude distribution of the two-dimensional radiated electric field measured by the measuring means to the aperture position of the antenna under test, and replaces the amplitude distribution of the outer region in the aperture plane with zero. A distribution replacement unit and a phase estimation unit that field-converts the amplitude distribution of the two-dimensional radiation electric field after the replacement into the measurement surface position of the measurement probe and estimates the phase distribution on the measurement surface are provided.
[0019]
  The antenna measurement method according to the present invention is adapted to obtain the amplitude distribution and phase distribution of a two-dimensional electric fieldWhile field-converting the aperture position of the antenna under test, the amplitude distribution and phase distribution of the two-dimensional electric field are field-converted to the virtual wave source position of the unwanted wave and included in the amplitude distribution and phase distribution of the two-dimensional electric field The unnecessary wave component is calculated, and the unnecessary wave component is field-converted to the aperture surface position of the antenna under test.The unwanted wave component is removed.
[0020]
In the antenna measurement method according to the present invention, the amplitude distribution of the two-dimensional electric field is field-converted to the aperture surface position of the test antenna, the amplitude distribution of the outer region in the aperture surface is replaced with zero, and the two-dimensional electric field after the replacement Is converted into a measurement surface position of the measurement probe, and the phase distribution on the measurement surface is estimated.
[0021]
In the antenna measurement method according to the present invention, the amplitude distribution and phase distribution of the two-dimensional radiation electric field are field-converted to the aperture surface position of the test antenna, and the amplitude distribution and phase distribution of the outer region in the aperture surface are replaced with zero, The amplitude distribution and phase distribution of the two-dimensional radiated electric field after the replacement are field-converted to the measurement surface position of the measurement probe, and the amplitude distribution and phase distribution in the region outside the measurement angle range in the measurement probe are estimated. It is a thing.
[0022]
In the antenna measurement method according to the present invention, the amplitude distribution of the two-dimensional radiated electric field is field-converted to the aperture position of the antenna under test, the amplitude distribution of the outer region in the aperture plane is replaced with zero, and the two-dimensional after the replacement The amplitude distribution of the radiated electric field is field-converted to the measurement surface position of the measurement probe, and the phase distribution on the measurement surface is estimated.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below.
Embodiment 1 FIG.
FIG. 1 is a block diagram showing an antenna measurement apparatus according to Embodiment 1 of the present invention. In the figure, 21 is a transmitter for transmitting radio waves to a test antenna 22, 22 is connected to a transmitter 21, and a transmitter 21 is shown. A test antenna that radiates radio waves transmitted from the space, 23 is a measurement probe that measures the amplitude distribution and phase distribution of a two-dimensional electric field in the vicinity of the test antenna 22, and 24 is measured by the measurement probe 23. This is a receiver that takes in the amplitude distribution and phase distribution of a two-dimensional electric field as a received signal.
The measurement probe 23 and the receiver 24 constitute measurement means.
[0024]
  25 is a planar scanner that scans the measurement probe 23 in two dimensions, 26 is a scanner controller that controls the scanning of the planar scanner 25, 27 is a pattern display that accumulates and visualizes the two-dimensional electric field, and 28 is a two-dimensional electric field. Field conversion of the amplitude distribution and phase distribution into virtual wave source positions of unnecessary waves, and calculation of unnecessary wave components included in the amplitude distribution and phase distribution of the two-dimensional electric field, the amplitude distribution and phase distribution of the two-dimensional electric field Unnecessary wave removal processor to remove unwanted wave components fromFirst and second field conversion means;Unnecessary wave removing means) 29 is a scanning of the planar scanner 25 in the x direction, and 30 is a scanning of the planar scanner 25 in the y direction.
  FIG. 2 is a flowchart showing an antenna measurement method according to Embodiment 1 of the present invention.
[0025]
Next, the operation will be described.
The radio wave transmitted from the transmitter 21 is radiated from the test antenna 22. The radio wave radiated into this space is received by the measurement probe 23 and taken out as a received signal by the receiver 24.
[0026]
That is, the two-dimensional electric field distribution is received by the scanning 29 in the x direction and the scanning 30 in the y direction by the planar scanner 25 of the measurement probe 23 (step ST11).
Hereinafter, the principle by which the unnecessary wave removal arithmetic processor 28 removes the unnecessary wave component from the received signal will be described with reference to FIG.
[0027]
First, when the measurement surface of the measurement probe 23 is set to z = zm, the unnecessary wave elimination arithmetic processor 28 provides a measurement value of a two-dimensional electric field distribution (amplitude distribution and phase distribution of a two-dimensional electric field) by a plane wave expansion method. By performing field conversion to a position (z = 0) on the surface including the aperture surface of the test antenna 22, a two-dimensional electric field distribution on the aperture surface of the test antenna 22 is obtained (step ST12).
[0028]
Then, the unnecessary wave removal arithmetic processing unit 28 changes the electric field (amplitude, phase) outside the opening surface of the antenna under test 22 to 0, and obtains the electric field distribution inside the opening surface (step ST13).
On the other hand, in order to obtain the unwanted wave component included in the received signal, the electric field (amplitude, phase) inside the aperture surface of the antenna under test 22 is changed to 0, and the wave source of the unwanted wave in the negative z direction by the plane wave expansion method. Field conversion is performed to the position (z = zi) (step ST14).
Here, since the wave source position of the unnecessary wave can be estimated by the beam waist, z = zi is taken as the beam waist position. There is actually no wave source in this part, but since it is considered that there is a virtual wave source of unnecessary waves, it will be called an image of unnecessary waves.
[0029]
In the two-dimensional electric field distribution field-converted to the position of z = zi, the unnecessary wave elimination arithmetic processor 28 sets the electric field (amplitude, phase), which is an image of this unnecessary wave, to 0, and 2 at the position of z = zi. Field conversion is again performed from the three-dimensional electric field distribution to the position of z = 0, and the electric field distribution outside the aperture surface of the antenna 22 is estimated (step ST15).
[0030]
Then, the unnecessary wave elimination arithmetic processor 28 combines the estimated electric field distribution outside the aperture surface of the antenna under test 22 with the electric field distribution inside the aperture surface of the antenna under test 22 previously obtained, and is unnecessary. The two-dimensional electric field distribution on the aperture surface of the antenna under test 22 from which the wave component has been removed is obtained (step ST16).
Thereby, a far radiation pattern can be obtained by performing field conversion by the plane wave expansion method without changing the distance between the antenna under test 22 and the measurement probe 23.
[0031]
FIG. 4 shows the result obtained by actual measurement. FIG. 4A shows a far radiation pattern in a horizontal plane and a vertical plane including unnecessary waves obtained by direct field conversion from near-field measurement in an anechoic chamber. FIG. 6B shows far radiation patterns in the horizontal plane and the vertical plane obtained by actually performing the measurement in the anechoic chamber according to the first embodiment and performing field conversion.
[0032]
For comparison, the far-field radiation pattern in the horizontal plane measured directly in the far-field by selecting the outdoor with a good measurement environment is indicated by a dotted line. In the figure (a), the shape of the main beam is greatly changed due to the influence of unnecessary waves, whereas in the figure (b), the main beam is in good agreement with the dotted line, and unnecessary waves are removed. I understand.
[0033]
As is apparent from the above, according to the first embodiment, the amplitude distribution and phase distribution of the two-dimensional electric field are field-converted into virtual wave source positions of unnecessary waves, and the amplitude distribution and phase distribution of the two-dimensional electric field are converted. The unnecessary wave component included in the calculation is calculated, and the unnecessary wave component is removed from the amplitude distribution and phase distribution of the two-dimensional electric field. Therefore, high accuracy is achieved in a short time without providing a driving device that can change the measurement distance. The effect which can perform a simple measurement is produced.
[0034]
Embodiment 2. FIG.
5 is a block diagram showing an antenna measurement apparatus according to Embodiment 2 of the present invention. In the figure, the same reference numerals as those in FIG. Reference numeral 31 denotes a power receiver (measuring means) that takes in the amplitude distribution of the two-dimensional electric field measured by the measurement probe 23 as a received signal, and 32 denotes the amplitude distribution of the two-dimensional electric field output from the power receiver 31 of the test antenna 22. Field conversion to the position of the aperture surface replaces the amplitude distribution of the outer region in the aperture surface with zero, and field conversion of the amplitude distribution of the two-dimensional electric field after the replacement to the measurement surface position of the measurement probe 23 It is a neighborhood phase pattern restorer (amplitude distribution replacement means, phase estimation means) for estimating the phase distribution on the measurement surface.
FIG. 6 is a flowchart showing an antenna measurement method according to Embodiment 2 of the present invention.
[0035]
Next, the operation will be described.
The radio wave transmitted from the transmitter 21 is radiated from the test antenna 22. The radio wave radiated into this space is received by the measurement probe 23, and only the power (amplitude distribution) of the received electric field distribution is extracted as a signal by the power receiver 31.
[0036]
Hereinafter, the principle by which the near phase pattern restoring unit 32 estimates the near field phase pattern will be described.
First, when the neighboring phase pattern restoration unit 32 obtains an amplitude measurement value at z = z1 (step ST21), the initial value of the phase distribution is assumed by calculation, and a two-dimensional electric field distribution (amplitude distribution) at z = z1 is assumed. To do.
[0037]
Then, the near phase pattern restoring unit 32 calculates the two-dimensional electric field distribution at the position of z = 0 including the opening surface of the antenna 22 to be tested by the plane wave expansion method from the two-dimensional electric field distribution at the position of z = z1. (Step ST22).
The near phase pattern restoring unit 32 changes the electric field (amplitude) in the outer region of the aperture surface of the antenna under test 22 to 0 (step ST23), performs field conversion to the position of z = z1 by the plane wave expansion method, and z = A two-dimensional electric field distribution at the position z1 is calculated to obtain a phase distribution at the position z = z1 (step ST24).
[0038]
The difference between this phase distribution and the phase distribution assumed as an initial value is obtained. By repeating the arithmetic processing described above, the difference in the phase distribution is made sufficiently small, and the converged phase distribution is set as an estimated value (steps ST25 to ST27). Since a two-dimensional electric field distribution of z = z1 is obtained from the phase distribution estimated value and the amplitude distribution measurement value, a far radiation pattern can be obtained by a plane wave expansion method.
As a result, errors due to phase fluctuations caused by millimeter waves and submillimeter waves are eliminated, and measurement accuracy can be improved.
[0039]
As is apparent from the above, according to the second embodiment, the amplitude distribution of the two-dimensional electric field is field-converted to the position of the aperture surface of the antenna under test 22 and the amplitude distribution in the outer region on the aperture surface is replaced with zero. Since the configuration is such that the amplitude distribution of the two-dimensional electric field after the replacement is field-converted to the measurement surface position of the measurement probe 23 and the phase distribution on the measurement surface is estimated, a driving device that varies the measurement distance is provided. Therefore, it is possible to estimate the phase distribution on the measurement surface of the measurement probe 23, and as a result, it is possible to perform highly accurate measurement in a short time.
[0040]
Embodiment 3 FIG.
7 is a block diagram showing an antenna measurement apparatus according to Embodiment 3 of the present invention. In the figure, the same reference numerals as those in FIG. 41 is a turntable that mounts the antenna under test 22 and changes its posture in two axes, 42 is a turntable controller that controls the drive of the turntable 41, 43 is an elevation scan of the turntable 41, and 44 is the orientation of the turntable 41. An angular scan 45 field-converts the amplitude distribution and phase distribution of the two-dimensional radiated electric field output from the receiver 24 to the position of the aperture surface of the test antenna 22, and zeros the amplitude distribution and phase distribution of the outer region on the aperture surface. And the field distribution of the amplitude distribution and phase distribution of the two-dimensional radiated electric field after the replacement into the measurement surface position of the measurement probe 23, and the amplitude distribution and phase in the region outside the measurement angle range in the measurement probe 23 This is a resolution restorer (electric field replacement means, electric field estimation means) for estimating the distribution.
[0041]
Next, the operation will be described.
The radio wave transmitted from the transmitter 21 is radiated from the measurement probe 23. The radio wave radiated into this space is received by the antenna under test 22 and taken out as a received signal by the receiver 24.
[0042]
By changing the posture of the turntable 41 with two axes by the elevation scanning 43 and the azimuth scanning 44, the two-dimensional radiation electric field distribution (amplitude distribution and phase distribution) of the antenna 22 under test is measured. The measurement angle range is finite in consideration of the influence of ambient reflection and the measurement time.
[0043]
The resolution restoring unit 45 estimates the radiated electric field in the angular range outside the measurement range from the measured value of the two-dimensional radiated electric field distribution, and acquires the aperture distribution with improved spatial resolution.
Hereinafter, the principle of improving the resolution on the aperture plane by the resolution restoring unit 45 will be described with reference to FIG.
[0044]
First, the resolution restoring unit 45 measures a two-dimensional radiation electric field distribution (amplitude distribution and phase distribution) on a spherical surface at a distance R = Rm. An initial value of 0 is assumed as the radiation electric field in the region outside the measurement angle range. The two-dimensional radiation electric field distribution (including the initial value) in an angle range wider than the measurement angle range is field-converted to the aperture surface position of the antenna under test 22 by the plane wave expansion method, and the in-plane including the aperture surface of the antenna under test 22 is obtained. An aperture electric field distribution at z = 0 is obtained.
[0045]
Then, the resolution restoring unit 45 changes the electric field in the outer region of the aperture surface of the antenna under test 22 to 0 and again performs field conversion by the plane wave expansion method to obtain the radiation electric field distribution on the spherical surface of R = Rm, and measure Estimate the radiated electric field distribution outside the angular range.
The resolution restoring unit 45 combines the estimated radiated electric field distribution and the measured radiated electric field distribution, and performs the arithmetic processing indicated by the thick arrows in the figure until the estimated radiated electric field distribution outside the measurement angle range converges. Repeat. The wide-angle electric field distribution is not affected by the ambient reflection due to such an estimated value, and based on this, a high-resolution aperture distribution can be obtained more accurately.
[0046]
As apparent from the above, according to the third embodiment, the amplitude distribution and phase distribution of the two-dimensional radiation electric field are field-converted to the position of the aperture surface of the antenna under test 22 and the amplitude distribution of the outer region in the aperture surface is obtained. And the phase distribution is replaced with zero, and the amplitude distribution and phase distribution of the two-dimensional radiated electric field after the replacement are field-converted to the measurement surface position of the measurement probe 23 and the region outside the measurement angle range of the measurement probe 23 is converted. Since the configuration is such that the amplitude distribution and the phase distribution are estimated, there is an effect that high-precision measurement can be performed in a short time without providing a driving device that varies the measurement distance.
[0047]
Embodiment 4 FIG.
9 is a block diagram showing an antenna measurement apparatus according to Embodiment 4 of the present invention. In the figure, the same reference numerals as those in FIG.
46 field-converts the amplitude distribution of the two-dimensional radiated electric field output from the power receiver 31 to the position of the aperture surface of the antenna under test 22 and replaces the amplitude distribution of the outer region in the aperture surface with zero, This is a far phase pattern restoring device (amplitude distribution replacement means, phase estimation means) for field-converting the amplitude distribution of the two-dimensional radiation electric field to the measurement surface position of the measurement probe 23 and estimating the phase distribution on the measurement surface.
FIG. 10 is a flowchart showing an antenna measurement method according to Embodiment 4 of the present invention.
[0048]
Next, the operation will be described.
The radio wave transmitted from the transmitter 21 is radiated from the measurement probe 23. The radio wave radiated into this space is received by the antenna under test 22, and only the power (amplitude distribution) of the received electric field is extracted as a signal by the power receiver 31.
By changing the posture of the turntable 41 with two axes by the elevation scan 43 and the azimuth scan 44, the two-dimensional electric field amplitude radiation pattern of the antenna 22 under test is measured.
[0049]
Hereinafter, the principle by which the far phase pattern restoring unit 46 estimates the far field phase pattern will be described.
First, when the far phase pattern restoring unit 46 obtains an amplitude measurement value at R = R1 (step ST31), the initial value of the phase distribution is assumed by calculation, and a two-dimensional radiation electric field distribution at R = R1 is assumed.
[0050]
Then, the far phase pattern restoring unit 46 calculates the two-dimensional radiation electric field distribution at the position of z = 0 including the opening surface of the test antenna 22 from the two-dimensional radiation electric field distribution at the position of R = R1 by the plane wave expansion method. Calculate (step ST32).
The far phase pattern restoring unit 46 changes the electric field (amplitude) in the region outside the aperture surface of the antenna under test 22 to 0 (step ST33), performs field conversion to the position of R = R1 by plane wave expansion, and R = A two-dimensional radiation electric field distribution at the position of R1 is calculated to obtain a phase distribution at the position of R = R1 (step ST34).
[0051]
The difference between this phase distribution and the phase distribution assumed as an initial value is obtained. By repeating the arithmetic processing described above, the difference in the phase distribution is made sufficiently small, and the converged phase distribution is set as an estimated value (steps ST35 to ST37). Since the two-dimensional electric field distribution of R = R1 is obtained from the phase distribution estimated value and the amplitude distribution measured value, the aperture electric field distribution can be obtained by the plane wave expansion method.
As a result, errors due to phase fluctuations caused by millimeter waves and submillimeter waves are eliminated, and measurement accuracy can be improved.
[0052]
As is apparent from the above, according to the fourth embodiment, the amplitude distribution of the two-dimensional radiation electric field is field-converted to the position of the aperture surface of the antenna under test 22 and the amplitude distribution of the outer region on the aperture surface is made zero. Since the configuration is such that the amplitude distribution of the two-dimensional radiated electric field after the replacement is field-converted to the measurement surface position of the measurement probe 23 and the phase distribution on the measurement surface is estimated, the driving device that varies the measurement distance The phase distribution on the measurement surface of the measurement probe 23 can be estimated without providing the measurement result. As a result, an effect of performing highly accurate measurement in a short time is obtained.
[0053]
【The invention's effect】
  As described above, according to the present invention, the amplitude distribution and phase distribution of the two-dimensional electric field measured by the measuring means are obtained.First field conversion means for field conversion to the aperture surface position of the antenna under test, and the amplitude distribution and phase distribution of the two-dimensional electric field field-converted by the first field conversion means as virtual wave source positions of unnecessary waves Second field conversion means for performing field conversion, calculating unnecessary wave components included in the amplitude distribution and phase distribution of the two-dimensional electric field, and field-converting the unnecessary wave components to the aperture position of the antenna under test is provided; The unnecessary wave component field-converted by the second field conversion means is removed from the amplitude distribution and phase distribution of the two-dimensional electric field field-converted by the first field conversion means.Since it comprised, there exists an effect which can perform a highly accurate measurement in a short time, without providing the drive device which varies a measurement distance.
[0054]
According to this invention, the amplitude distribution replacing means for field-converting the amplitude distribution of the two-dimensional electric field measured by the measuring means to the aperture position of the antenna under test and replacing the amplitude distribution of the outer region in the aperture plane with zero. The field distribution of the amplitude distribution of the two-dimensional electric field after the replacement is converted into the measurement surface position of the probe in the measurement means, and the phase estimation means for estimating the phase distribution on the measurement surface is provided. The phase distribution on the measurement surface of the measurement probe can be estimated without providing a variable driving device, and as a result, there is an effect that high-precision measurement can be performed in a short time.
[0055]
According to this invention, the amplitude distribution and phase distribution of the two-dimensional radiation electric field measured by the measuring means are field-converted to the aperture position of the antenna under test, and the amplitude distribution and phase distribution of the outer region in the aperture plane are zeroed. Electric field replacement means to be replaced with, and the amplitude distribution and phase distribution of the two-dimensional radiated electric field after the replacement to the measurement surface position of the measurement probe, and the amplitude distribution of the outer region of the measurement angle range in the measurement probe and Since the electric field estimation means for estimating the phase distribution is provided, there is an effect that high-precision measurement can be performed in a short time without providing a driving device that varies the measurement distance.
[0056]
According to the present invention, the amplitude distribution replacing means for field-converting the amplitude distribution of the two-dimensional radiation electric field measured by the measuring means to the position of the aperture surface of the antenna under test and replacing the amplitude distribution in the outer region of the aperture surface with zero. And a phase estimation means for estimating the phase distribution on the measurement surface by field-converting the amplitude distribution of the two-dimensional radiated electric field after the replacement to the measurement surface position of the measurement probe. The phase distribution on the measurement surface of the measurement probe can be estimated without providing a drive device that can vary the above. As a result, there is an effect that highly accurate measurement can be performed in a short time.
[0057]
  According to the present invention, the amplitude distribution and phase distribution of the two-dimensional electric field areWhile field-converting the aperture position of the antenna under test, the amplitude distribution and phase distribution of the two-dimensional electric field are field-converted to the virtual wave source position of the unwanted wave and included in the amplitude distribution and phase distribution of the two-dimensional electric field The unnecessary wave component is calculated, and the unnecessary wave component is field-converted to the aperture surface position of the antenna under test.Since the configuration is such that unnecessary wave components are removed, there is an effect that high-accuracy measurement can be performed in a short time without providing a driving device that varies the measurement distance.
[0058]
According to this invention, the amplitude distribution of the two-dimensional electric field is field-converted to the aperture position of the antenna under test, the amplitude distribution of the outer region in the aperture plane is replaced with zero, and the amplitude distribution of the two-dimensional electric field after the replacement Is converted into the measurement surface position of the measurement probe, and the phase distribution on the measurement surface is estimated, so that the phase distribution on the measurement surface of the measurement probe can be provided without providing a drive unit that varies the measurement distance. As a result, it is possible to perform highly accurate measurement in a short time.
[0059]
According to this invention, the amplitude distribution and phase distribution of the two-dimensional radiated electric field are field-converted to the aperture surface position of the antenna under test, and the amplitude distribution and phase distribution of the outer region in the aperture surface are replaced with zero, and after the replacement The field distribution of the amplitude distribution and phase distribution of the two-dimensional radiated electric field is converted into the measurement surface position of the measurement probe, and the amplitude distribution and phase distribution in the region outside the measurement angle range of the measurement probe are estimated. There is an effect that high-precision measurement can be performed in a short time without providing a drive device that varies the measurement distance.
[0060]
According to this invention, the amplitude distribution of the two-dimensional radiated electric field is field-converted to the position of the aperture surface of the test antenna, the amplitude distribution of the outer region in the aperture surface is replaced with zero, and Since the amplitude distribution is field-converted to the measurement surface position of the measurement probe and the phase distribution on the measurement surface is estimated, the measurement surface of the measurement probe can be measured without providing a driving device that varies the measurement distance. The phase distribution can be estimated, and as a result, there is an effect that highly accurate measurement can be performed in a short time.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an antenna measurement apparatus according to Embodiment 1 of the present invention.
FIG. 2 is a flowchart showing an antenna measurement method according to Embodiment 1 of the present invention.
FIG. 3 is an explanatory diagram showing an operation principle of an unnecessary wave removal arithmetic processing unit.
FIG. 4 is a graph showing a far radiation pattern in a horizontal plane and a vertical plane.
FIG. 5 is a block diagram showing an antenna measurement apparatus according to Embodiment 2 of the present invention.
FIG. 6 is a flowchart showing an antenna measurement method according to Embodiment 2 of the present invention.
FIG. 7 is a block diagram showing an antenna measurement apparatus according to Embodiment 3 of the present invention.
FIG. 8 is an explanatory diagram showing an operation principle of a resolution restorer.
FIG. 9 is a block diagram showing an antenna measurement apparatus according to Embodiment 4 of the present invention.
FIG. 10 is a flowchart showing an antenna measurement method according to Embodiment 4 of the present invention.
FIG. 11 is a configuration diagram illustrating a conventional antenna measurement apparatus.
FIG. 12 is a block diagram showing a conventional antenna measurement apparatus.
FIG. 13 is a flowchart showing the operation of a conventional antenna measurement apparatus.
[Explanation of symbols]
  21 transmitter, 22 antenna under test, 23 probe for measurement (measuring means), 24 receiver (measuring means), 25 plane scanner, 26 scanner controller, 27 pattern display, 28 unnecessary wave elimination arithmetic processor (First and second field conversion means;Unnecessary wave removing means), 29 scanning in the x direction of the planar scanner 25, 30 scanning in the y direction of the planar scanner 25, 31 power receiver (measuring means), 32 proximity phase pattern restoring unit (amplitude distribution replacing means, phase estimating means) ), 41 turntable, 42 turntable controller, 43 elevation scan of turntable 41, azimuth scan of turntable 41, 45 resolution restorer (electric field replacement means, electric field estimation means), 46 far phase pattern restorer ( Amplitude distribution replacement means, phase estimation means).

Claims

Measurement means for measuring the amplitude distribution and phase distribution of the two-dimensional electric field at a position near the test antenna, and the amplitude distribution and phase distribution of the two-dimensional electric field measured by the measurement means in the position of the aperture surface of the test antenna First field conversion means for converting, and field conversion of the amplitude distribution and phase distribution of the two-dimensional electric field field-converted by the first field conversion means into virtual wave source positions of unnecessary waves, and the two-dimensional electric field Calculating the unnecessary wave component included in the amplitude distribution and the phase distribution of the signal, and converting the unnecessary wave component to the position of the aperture surface of the antenna under test, and a field by the first field converting unit. the converted two-dimensional electric field amplitude distribution and phase distribution required is field converted by said second field conversion means from NamiNaru Antenna measurement system that includes a spurious wave removing means for removing.

A measuring means for measuring the amplitude distribution of the two-dimensional electric field at a position near the antenna under test, and the field distribution of the amplitude distribution of the two-dimensional electric field measured by the measuring means into the aperture surface position of the antenna under test, Amplitude distribution replacement means for replacing the amplitude distribution of the outer region on the surface with zero, and the amplitude distribution of the two-dimensional electric field after replacement by the amplitude distribution replacement means are field-converted to the measurement surface position of the probe in the measurement means, and the measurement is performed. An antenna measurement apparatus comprising phase estimation means for estimating a phase distribution on a surface.

Measuring means for measuring the amplitude distribution and phase distribution of the two-dimensional radiated electric field of the antenna under test, and field conversion of the amplitude distribution and phase distribution of the two-dimensional radiated electric field measured by the measuring means into the aperture plane position of the antenna under test Then, the electric field replacement means for replacing the amplitude distribution and phase distribution of the outer region on the opening surface with zero, and the amplitude distribution and phase distribution of the two-dimensional radiated electric field after the replacement by the electric field replacement means are measured on the measurement surface position of the measurement probe. An antenna measurement apparatus comprising: an electric field estimation unit that field-converts the amplitude distribution and the phase distribution in a region outside the measurement angle range of the measurement probe.

Measuring means for measuring the amplitude distribution of the two-dimensional radiated electric field of the antenna under test, field conversion of the amplitude distribution of the two-dimensional radiated electric field measured by the measuring means into the aperture surface position of the antenna under test, Amplitude distribution replacement means for replacing the amplitude distribution of the outer region with zero, and field conversion of the amplitude distribution of the two-dimensional radiated electric field after replacement by the amplitude distribution replacement means to the measurement surface position of the measurement probe, An antenna measurement apparatus comprising phase estimation means for estimating a phase distribution.

When the amplitude distribution and phase distribution of the two-dimensional electric field in the vicinity of the test antenna are measured, the amplitude distribution and phase distribution of the two-dimensional electric field are field-converted to the aperture surface position of the test antenna, while the two-dimensional electric field The amplitude distribution and the phase distribution are field-converted into virtual wave source positions of unnecessary waves, and unnecessary wave components included in the amplitude distribution and phase distribution of the two-dimensional electric field are calculated. An antenna measurement method in which the unnecessary wave component is removed from the amplitude distribution and phase distribution of the two-dimensional electric field at the opening surface position of the antenna under test by performing field conversion to the opening surface position .

When the amplitude distribution of the two-dimensional electric field at the position near the test antenna is measured, the amplitude distribution of the two-dimensional electric field is field-converted to the aperture surface position of the test antenna, and the amplitude distribution of the outer region on the aperture surface is zero. An antenna measurement method in which the amplitude distribution of the two-dimensional electric field after the replacement is field-converted to the measurement surface position of the measurement probe and the phase distribution on the measurement surface is estimated.

When the amplitude distribution and phase distribution of the two-dimensional radiated electric field of the test antenna are measured, the amplitude distribution and phase distribution of the two-dimensional radiated electric field are field-converted to the aperture surface position of the test antenna, and the outer region on the aperture surface The amplitude distribution and phase distribution of the measurement probe are replaced with zero, the amplitude distribution and phase distribution of the two-dimensional radiation electric field after the replacement are field-converted to the measurement surface position of the measurement probe, and the region outside the measurement angle range in the measurement probe Antenna measurement method for estimating the amplitude distribution and phase distribution of the antenna.

When the amplitude distribution of the two-dimensional radiated electric field of the antenna under test is measured, the amplitude distribution of the two-dimensional radiated electric field is field-converted to the position of the aperture surface of the antenna under test, and the amplitude distribution of the outer region in the aperture plane is made zero. An antenna measurement method that replaces, field-converts the amplitude distribution of the two-dimensional radiated electric field after the replacement to the measurement surface position of the measurement probe, and estimates the phase distribution on the measurement surface.