Design of FIR fan filters used for beamspace adaptive array for broadband signals

We propose a method of designing FIR fan filters used for a multiple beamformer in a beamspace adaptive array for broadband signals. Approximation is achieved by the combination of spectral transformation and the window method so that the directional pattern of the resulting fan filter may be virtually independent of frequency including those for sidelobe characteristics. Through the implementation of fan filters designed in the proposed method, we demonstrate that it is possible to suppress interference signals with a wide fractional bandwidth using a beamspace adaptive array.