Direction Finding in the Presence of Direction-Dependent Mutual Coupling

Direction-of-arrival (DOA) estimation in the presence of mutual coupling (MC) is an important problem in direction-finding applications. Previous methods in the literature assume that the MC in the array is modeled with a single direction-independent MC matrix. However, this assumption is not valid in practice where the effect of MC varies for different directions. In this letter, a new method is proposed in order to estimate both source DOA angles and MC coefficients in the presence of direction-dependent MC. The proposed method iteratively estimates the source DOA angles using the MUSIC algorithm. In order to estimate the direction-dependent MC coefficients, a unified transformation approach is proposed, which can be applied for any array geometry. Then, a convex minimization problem is outlined using the signal-noise subspace orthogonality. The performance of the proposed method is evaluated for uniform linear and circular arrays. It is shown that the proposed method effectively estimates both source and array coupling parameters and it has superior performance than the conventional techniques.