A far-field measurement method for large size antenna by using synthetic aperture antenna

It is difficult to obtain far-field radiation patterns of electrically large scale antenna, for example a base station array antenna of mobile communications, when the distance between Tx and Rx is less than the Rayleigh distance 2D
²
/lambda, where D is the aperture of antenna and lambda is the wave length. A far-field measurement method for such antennas using a synthetic aperture antenna and a conventional pattern measurement system has been proposed in the previous report in order to overcome these problems. The arc shaped synthetic aperture antenna generates quasi plane waves around AUT (antenna under the test) to obtain far-field patterns even if the distance is shorter than 2D
²
/lambda. In this paper, we investigate some measurement parameters in detail, and the validity of this proposed measurement method is clarified by experiment using 8 GHz horn array antenna.