DoA Estimation in the Presence of the Unknown Mutual Coupling Using a UCA with Directive Antennas

In this paper, a method is proposed to compensate the effect of mutual coupling in a Uniform Circular Array (UCA) with directional antennas. UCA is a suitable array geometry, because it leads to uniform precision of Direction of Arrival (DoA) estimation over the entire range of azimuth angles in [0,360] degree. However, the mutual coupling effect of a UCA can be much stronger than that of a uniform linear array (ULA). In this paper, we will show that using directive antennas will improve the accuracy of direction of arrival estimation. In order to reduce the effect of mutual coupling on the performance of direction of arrival estimation, an auto-calibration method will be proposed. In the proposed algorithm, direction of arrival and mutual coupling matrix are estimated using an iterative method. Simulation results show that a UCA with application of the proposed algorithm has a better performance in comparison to the array with isotropic antennas at the presence of mutual coupling.