A Study of Compensation for Temporal and Spatial Physical Temperature Variation in Total Power Radiometers

This paper describes a study of compensation for the physical temperature variation in microwave radiometers. The compensation method is derived by using a multivariable least squares estimation with a radiometer model with temperature-dependent parameters for three system blocks. The feasibility of the method is demonstrated with several experiments with a Ka-band total power radiometer and a temperature control system developed to test the method in various thermal conditions. The results show that the compensation method can be applied to calibrate microwave radiometers without switching systems and is expected to compensate internal temperature gradients and temporal variation of physical temperature.