Analytical Model of Diurnal Temperature for a Radome Enclosed Antenna

A critical design consideration for the Haystack Ultrawide-band Satellite Imaging Radar's (HUSIR) with respect to its performance at W-band is thermal distortion. This is because thermal distortion affects the surface accuracy of a parabolic reflector. For example, an extremely tight surface tolerance, ~100 microns root-mean-squared, is required to obtain antenna performance efficiency close to 85 percent. Thermal control is one method for mitigating this distortion. Cost effective thermal control relies on a model that rapidly and accurately predicts the antenna's temperature. This work develops a simplified analytical model to predict the surface temperature of a metal antenna based on external diurnal temperature variations. The thermal energy balance of the radome/antenna captures the radome enclosed antenna temperature transients. This study also includes a parametric investigation to quantify the sensitivity of the model with respect to convection coefficients. The developed model generates results for four months, (February, April, August, and October). We compare some of these results to experimental measurements.