Mutual Coupling Compensation on Spectral-based DOA Algorithm

Direction of arrival (DOA) estimation using isotropic antenna arrays are commonly being implemented without considering the mutual coupling effect in between the array elements. This paper presents an analysis of DOA estimation with mutual coupling compensation using a linear antenna array. Mutual coupling effect is represented by mutual coupling coefficients and taken into account when calculating the array output. The mutual coupling compensation technique exploits a banded mutual coupling matrix to reduce the computational complexity. The banded matrix reflects the relationship between mutual coupling effect and the element spacing in an antenna array. The analysis is being carried out using the Capon algorithm, one of spectral-based DOA algorithms, for estimating the DOA of incoming signals. Computer simulations are performed to show the performance of the mutual coupling compensation technique on DOA estimation. Simulation results show that, in term of estimation resolution, the mutual coupling compensation technique manages to obtain a comparable results compared to the case without mutual coupling consideration. However, the mutual coupling compensation technique produces significant estimation error compared to the case without mutual coupling. The study concludes that the banded matrix of mutual coupling coefficients should be properly designed to improve the performance of mutual coupling compensation technique in DOA estimation.