Direction-of-Arrival Estimation: Measurement using compact antenna arrays under the influence of mutual coupling

This article investigates the accuracy of direction-of-arrival (DOA) estimations using compact antenna arrays under the influence of mutual coupling. We model the entire electromagnetic problem using the moment method such that the undesirable mutual coupling effect is taken into account accurately. We decouple the received signals using the receiving-mutual-impedance method (RMIM) and perform the DOA estimation using the matrix pencil method (MPM) through a Monte Carlo simulation approach. Although the signals are strongly distorted by mutual coupling, we show that increasing the number of elements within a small array aperture can significantly improve the estimation accuracy. The findings show that the RMIM can effectively compensate for mutual coupling for arrays with an aperture of a factor of a wavelength. Such findings are crucial to the development of compact arrays in various applications.