On the use of reconfigurable antenna arrays for DoA estimation of correlated signals

Direction of arrival (DoA) estimation is one of the key issues for many radar and wireless communications applications. In those applications, a major drawback is the presence of multiple paths resulting in highly correlated received signals. Spatial smoothing techniques along with multiple signal classification (MUSIC) algorithm is one of the key techniques to resolve such highly correlated signal directions. However, the performance of spatial smoothing employed with a legacy phased array is limited by the degrees of freedom of the array. In this work, we investigate the use reconfigurable antenna arrays (RAAs) along with MUSIC based DoA estimation algorithms. An RAA consists of individual elements with reconfigurable radiation patterns, and hence possesses a greater degrees of freedom. We propose a novel spatial smoothing technique that can utilize the additional degrees of freedom provided by RAAs and show that improved DoA estimation performance can be achieved. Numerical results indicate that the proposed approach improves the number of detected directions and the associated estimation errors.