Impact of Phase Center Displacement on Direction-of-Arrival Estimation using Multi-Mode Antennas

In this paper, we investigate the impact of the displacement of the phase centers of multi-mode antennas when applied for direction-of-arrival estimation. Based on electric far field samples, a mathematical approach is employed in order to calculate the phase center position for each mode. This knowledge is then integrated into the data model in order to improve the accuracy of the direction-of-arrival estimation using multi-mode antennas. Numerical simulations based on a maximum-likelihood estimator prove an enhanced performance compared to the case where the phase center displacement is neglected. The Cramer-Rao bound is considered as a benchmark to evaluate the results.