Research on Robust Broadband Beamformers Using Low-Order Statistics of Microphone Mismatches

Broadband beamformers are susceptible to microphone characteristics with mismatches. One classical robust design method against microphone mismatches uses a circular set to enclose the disturbance region of microphone errors and completes the design procedure by worst-case performance optimization. However, this method has drawbacks such as sensitivity to design parameters and over constraints, which lead to serious degradation in array response performance. To overcome this limitation, this paper proposes a robust design approach that utilizes the low order statistical characteristics of mismatch errors to optimize the worst-case mean performance of the beampattern. More importantly, this paper theoretically analyzes the differences between different methods, demonstrates the reasons for the superiority of the proposed method, and further verifies the advantages of the proposed method through simulation results.