屋内多重波伝搬環境において実験的にMIMOアンテナ性能を評価する方法，ならびに測定結果について報告する．実測結果を理論推定値と比較するためには，MIMOアンテナの受信場所における到来波分布パラメータを評価する必要があるが，本検討では送受信点間に電波吸収体を設置した簡易な見通し外条件の下で，仰角ガウス分布・アジマスー様分布モデルの到来波パラメータを推定している．また，半波長ダイポールアンテナを並列設置して構成される2.4GHz帯2×2MIMOアンテナを対象に，アンテナ素子間隔ならびにアンテナの傾斜角に対する固有値および伝送容量特性を上記環境下にて測定し，その結果を理論推定値と比較する．本検討手法はMIMOアンテナの屋内実験評価方法として有用であること，ならびに理論推定値が実測値とよく一致することを示す．%This paper describes a method for evaluating performance of MIMO antennas in indoor radio propagation environments and shows some measurement results. In order to compare measured results with theoretical predictions, it is necessary to find the environmental parameters such as the cross poralization power ratio (XPR) and the angular density function of incident waves arrived at moving antennas. In this study, the angular density functions for vertically and horizontally polarized waves are assumed to be Gaussian distribution in elevation and uniform distribution in azimuth, and their standard deviations are estimated by measurements in which the radio absorvers are simply used for constructing NLOS radio propagation environment. This paper also shows the measured results of a 2×2 MIMO antenna composed with half wavelength dipole antennas as functions of antenna spacing and its inclination angle, and compares with the thoretical predictions. This indoor measurement method is very useful for evaluating the MIMO antenna performance, and it is also confirmed that the theoretical predictions have a good agreement with measurements.
展开▼
