Evaluating Noise in Passive Beamforming Networks for Multibeam Applications

In this letter, we identify that the analysis in terms of noise of multibeam passive beamforming networks requires a proper formulation, in order not to overestimate the noise generated by the network. We show that the inherent spatial diversity offered by this type of networks results in an improvement of the signal-to-noise ratio, similar to the one obtained by digital architectures, with a penalty due to the insertion loss. To illustrate this phenomena, two generalized equivalent circuits are proposed are a numerical example is presented.