Abstract:

The mutual coupling problem of non-uniform linear array (NULA) is studied. Unlike uniform linear array (ULA), the mutual coupling matrix of NULA does not have the characteristics of banded symmetric Toeplitz, so it is more complex to deal with. First of all, according to the characteristics of the array structure, the mutual coupling matrix is transformed into the form of two ‘Toeplitz’ matrix subtractions. Thus, it is convenient to realize the decoupling of the angle and the mutual coupling coefficients. And then combining with the subspace principle, the direction of arrival (DOA) and the mutual coupling coefficient are estimated simultaneously. The algorithm does not require additional auxiliary correction source, and also it does not need non-linear high-dimensional search and iterative process, so the computation is small. Simulation results show that the proposed algorithm can estimate the signal angle and the mutual error coefficient well, which has the characteristics of high precision and strong resolution, hence, it can effectively solve the mutual coupling problem of the NULA.