On optimization of antennas without phase center for DOA estimation

Antennas without phase center (AWPC) are applied to resolve the less-sensors-than-sources problem in direction-of-arrival (DOA) estimation using subspace methods, typically, the well-known multiple signal classification (MUSIC) algorithm. This paper focuses on optimization of some design parameters of such antennas, including the rotation angle, the rotation step number and distances of two dipole couples, in order to improve the ambiguity and accuracy of all estimators which use AWPC structure. These optimization problems are formulated and solved by using Cramer-Rao bound (CRB) and ambiguity checking criteria. Specially, the parameters were optimized to avoid issues related to the ambiguity for half space localization problem while minimizing the CRB for improving the DOA estimation accuracy.