Impact of calibration on the performance of a total power radiometer

For current total power radiometers, the measurement of two different reference temperatures at least are necessary to be able to calibrate the radiometric receiver. In addition, we can note that two terms are essential to characterize the performance of a microwave radiometer : the radiometric sensitivity and the radiometric accuracy. On one hand, this paper will highlight the impact of the calibrations on the radiometric sensitivity. For that, some key elements as the gain stability or the number of calibration and their weighting are discussed. We will notably see that a trade off on these different parameters can be obtained in order to optimize this sensitivity. On the other hand, this paper will present the different elements that could affect the radiometric accuracy and it will focus on the elements related to the calibration.