On-Board Calibration Methods for Mechanical Distortions of Satellite Phased Array Antennas

In satellite phased-array antennas, mechanical distortions, which may be due to vibrations caused when launching the satellite into the orbit or thermal variations in the orbit, result in significant degradation of electrical performance. In this paper, two on-board calibration methods are proposed for such mechanical distortions: One compensates for the element phase differences resulting from mechanical distortions, and the other is used to set the best-fit phase distribution obtained from the measured phases. The latter method is effective even at a low signal-to-noise ratio (SNR). The proposed methods have been validated by experiments, through which the theoretically predicted calibration accuracy of the methods has been successfully reproduced.