Unified Definitions of Efficiencies and System Noise Temperature for Receiving Antenna Arrays

Two methods for defining the efficiencies and system noise temperature of a receiving antenna array have recently been developed, one based on the isotropic noise response of the array and the other on an equivalent system representation. This letter demonstrates the equivalence of the two formulations and proposes a new set of standard definitions of antenna figures of merit for beamforming arrays that accounts for the effect of interactions between antenna element mutual coupling and receiver noise on system performance.