Design of steerable and frequency invariant beamformers robust against microphone mismatches

Due to the presence of possibly moving sources in practical applications, it is of interest to design wideband beamformers with a steerable passband for microphone arrays. In this paper, the design approach of steerable and frequency invariant (SFI) wideband beamformers is presented, which is based on the Farrow structure and robust against microphone mismatches. The proposed method has a closed-form solution, thus has a lower computational complexity. Several design examples are presented to show the superior performance of the method over its existing counterpart in keeping a frequency invariant passband.