Whole-space ambiguity removal in DOA estimation by AWPC antenna

Antennas without phase center (AWPC) have been used to estimate direction of arrival (DOA) specially in less sensors than sources case. The similarity of two or more steering vectors corresponding to widely separated directions in the array manifold causes ambiguity in the DOA estimation. Recently, half-space ambiguity resolution has been done by optimizing the structure of the AWPC, based on Cramer-Rao bound. This paper further proposes a novel method for resolving whole-space ambiguity in the DOA estimation by using a uniform circular array (UCA) with multiple optimal AWPC sensors. The optimal number of AWPC sensors in moderate-size UCAs is also obtained by numerical optimization.