Convolution constrained robust beamforming techniques for broadband microphone array

Array imperfections are known to be a leading cause of performance deprivation for a broadband smart antenna array system. Directional constraints are imposed on the weights of an antenna array to obtain solutions of some constrained beamforming problems. For broadband antenna arrays, formulation of a constrained beamforming problem typically requires presteering the array using steering delays. These delays create implementation problems and cause loss of system performance in the presence of array imperfections. This paper presents new kind of constraints referred to as convolution constraints with robust diagonal loading techniques, which are easy to implement and eliminate the need for presteering delays. The simulation results show that the proposed processor has better performance than the existing processor to steer the main beam at any arbitrary direction without using presteering delays.