Low-Frequency Noise Sources and Gain Stability in Microwave Amplifiers for Radiometry

摘要

In this paper, the impact of low-frequency noise sources on the gain stability of microwave amplifiers is presented. The presence of a thermally activated relaxation process is experimentally demonstrated. To support the experiment, a mathematical model of this additional excess noise source is proposed in the Allan variance analysis. Different microwave amplifiers are also characterized and their stability is compared with the use of the Allan variance.