Analysis of the Noise Temperature of an Antenna Array Receiver

For evaluating effects of the interference mitigation technology on the sensitivity of an astronomical radio device, we propose a method to estimate the influence of the adaptive beam-forming technique on the noise temperature of an antenna array receiver system. Using a correct noise model we derive the relation between noise temperature and system parameters. We subsequently use the relation to analyze how the uncertainties of some system parameters (e.g., antenna gain, receiver gain, and system coupling) are affected by the noise temperature. We use simulations to test the influence of the current main adaptive beam-forming algorithm on the noise temperature. The results indicate that the interference mitigation processing based on the adaptive beam-forming technique is insufficient in cases that astronomical signals and interference signals severely overlap. It appears necessary to solve this problem by combining other interference mitigation methods in the temporal or frequency domain with the adaptive beam-forming technique. Our analysis results need to be further verified for real situations.