Spacecraft antenna measurement eliminating gravity effect by using planar near-field antenna measurement technique

Since spacecraft antennas are used in space, it is necessary to evaluate the mirror surface error and the electrical performance of the antenna in the gravity-free state. In order to execute such an evaluation on the ground, a measurement method is desired in which the effect of gravity can be separately evaluated. This article proposes a method that separately evaluates the mirror surface error inherent to the antenna and deformation by gravity, by rotating the antenna around the beam axis, and measuring the near field at each angle of rotation. An antenna is experimentally constructed, measured, and evaluated by the proposed method. (C) 2000 Scripta Technica, Electron Comm Jpn Pt 2, 83(3): 16-25, 2000.