Wideband and Reconfigurable Vector Antenna using Radiation Pattern Diversity for 3-D Direction-of-Arrival Estimation

Abstract : The direction finding performances of a novel passive , wideband and radiation pattern reconfigurable vector antenna are reported. Accurate estimation of the direction of arrival of incoming electromagnetic fields across the 3-D half-space is obtained over a 1.69:1 impedance bandwidth from the radiation pattern reconfigurability of a 4-port vector antenna. This antenna consists of only two orthogonal and co-located semi-circular arrays of Vivaldi antennas. Due to its reconfigurability, more radiation patterns can be used in addition to those commonly employed in standard vector antennas to estimate the direction of arrival of incoming electromagnetic fields. A new method based on the Cramer-Rao lower bound is proposed in order to select the radiation pattern diversity that improves the estimation accuracy across the overall bandwidth. Measured and simulated results are found in good agreement. The present study brings a further step towards developing new concepts of reconfigurable vector antennas.