Theory and design of uniform concentric circular arrays with frequency invariant characteristics

Abstract

This paper proposes a new digital beamformer for uniform concentric circular array (UCCA) having nearly frequency invariant (FI) characteristics. The basic principle is to transform the received signals to the phase mode and remove the frequency dependency of the individual phase mode through the use of a digital beamforming network. The far field pattern of the array is determined by a set of weights and it is approximately invariant over a wide range of frequencies. Compared with FI uniform circular array (UCA), FI UCCAs are able to achieve a wider bandwidth. Design examples are given to demonstrate the principle of the proposed UCCA-FIB and its application to broadband DOA estimation of coherent sources. © 2005 IEEE.published_or_final_versio