Array optimization applied in the near field of a microphone array

This paper describes the application of array optimization techniques in th e near-field of a microphone array. It is shown that the optimum weights ob tained for microphone spacing equal to a half wavelength are real, aside fr om the propagation delay, and inversely proportional to the distance from e ach microphone to the focal point, When the microphone spacing is less than half wavelength, the optimum weights are super-directive requiring both an amplitude and phase adjustment in addition to delay-and-sum beamforming, I n the super-directive regime, the maximum array gain increases as the dista nce to the focal points decreases. The technique is suitable for applicatio ns where the source of interest is located in the near-field region but int erfering sources are located farther from the array.