Design of broadband adaptive array based on DFT interpolation method

The computational cost of conventional broadband adaptive beamforming is very high. In this paper, a new algorithm of frequency invariant beamforming is presented, which combines with adaptive technology and DFT interpolation algorithm. Firstly, relationships between weights of a discrete sensor array and sensitivity distribution of a continuous linear array, which has a property of frequency invariant beam pattern, are introduced. Then, by employing the weight relationship between reference frequency and other frequency, the weights at other frequency are given by using DFT interpolation method. Lastly, the DFT interpolation method is applied to linearly constrained minimum variance broadband adaptive array. The theoretical and simulation results show that proposed algorithm can solve the minimum variance beamforming problem, and ensure the beam pattern invariant with frequency at the same time.