Effects of the element separation on the noise performance of receiving antenna arrays

Antenna arrays of closely separated elements can be used to achieve a large field of view of a radio telescope with highly efficient multiple beams. However, due to strong mutual coupling effects which exist in such dense arrays, the receiver noise can degrade. To reduce this noise degradation, the optimal noise match condition should be satisfied for all scan angles. This paper presents results of the noise performance analysis of small arrays of dipoles that were obtained for several element separation distances covering both conventional and dense arrays. The receiver noise temperatures are calculated for different noise match situations and the minimum noise temperature conditions are discussed.