Antenna performance predictions of a radio telescope subject to thermal perturbations

Abstract

Antenna performance predictions and calibration times are estimated on a 37 m diameter radio telescope subject to thermal perturbations. The telescope is designed to operate at frequencies up to 325 GHz with a one-way performance requirement of 1 dB loss in gain accounting for fabrication, alignment, gravity and thermal errors. Thermal gradients acting over the antenna structure due to diurnal air temperature variations are a significant contributor to degradations in antenna performance. Integrated thermal-structural-optical analyses were performed to predict antenna performance as a function of the diurnal variations. Based on the results, design requirements were imposed on the radome thermal control system and the rate of calibration of the hexapod mounted subreflector.