Zero location study of the beam response of the maximum output SINR beamformer

Based on the uniform linear array (ULA) structure, zero locations of the beam pattern of the maximum output SINR (signal-to-interference-plus-noise ratio) beamformer are investigated. It is shown that for an M-sensor array, M - 1 nulls have to be formed in the optimum beam response and all of them are located on the unit circle. Furthermore, the nulls of the beamformer may shift from the real interference DOA angles to achieve the optimum output SINR. Analysis based on a 3-element ULA is provided, supported by simulations.