The gain of array receiving signal is distorted due to the different gain of different frequency components in wideband signal；in order to solve the problem, an algorithm is proposed to improve constant beamwidth beamformer based on FIR. In this algorithm, the FIR filter array structure and microphone uniform line array features are utilized to determine the frequency range of constant beamwidth beamformer and obtain the array response with a constant beamwidth. In addition, the reference beam is designed to deal with the large fluctuation of the beamwidth between the adjacent cutoff frequencies, and the least square method is used to find the optimal weight. Finally, the optimal weight is normalized to gain a uniform gain. Computer simulation and experimental results verify the effectiveness of the algorithm.
