On the design of digital broadband beamformer for uniform circular array with frequency invariant characteristics

Abstract

In this paper, the design of digital uniform circular array - frequency invariant beamformer (UCA-FIB) is proposed. After transformation and removal of frequency dependency of the individual phase mode, the frequency invariant phase mode are linear combined with the spatial filter coefficients to form the far field pattern of the array. As the result, such beamformer is a wideband frequency invariant beamformer. For simultaneously beamforming, we propose a UCA-FIB DFT filterbank for concurrent beamforming in different direction. Design examples demonstrated that the proposed UCA-FIB can form deep nulls and sharp peaks with good FI characteristic while the UCA-FIB DFT can spatially divide the array neighboring area into small sectors efficiently.