Simulation Study of the Direction-of-Arrival Estimation and Digital Beamforming via Linear Antenna Arrays Depending on Mutual Coupling Based on the Method of Moments

The problem of designing antenna arrays for the spatial filtering taking into account mutual coupling between antenna elements is studied. The antenna arrays fulfil the Direction-of-Arrival (DOA) estimation with super-resolution, and then form a radiation pattern. For the task, several typical examples of antenna arrays have been obtained, which consist of common types of dielectrics and radiators. On the surface of different materials, currents of varying amplitude and direction are known to be created. The distribution creates a variable-magnitude mutual coupling. The phenomenon affects the final radiation pattern and the scattering matrix. Thus, mutual coupling strongly distorts the DOA-estimation and beamforming. Most of the references devoted to this topic consider mutual coupling, as a rule, from a theoretical point of view. In this paper, the modeling is performed according to the Method-of-Moments and the isolated pattern approach in order to analyze the DOA-estimation and beamforming depending on the dielectric and radiator materials. Several spatial pseudospectrums with super-resolution and time-domain signal processing following digital beamforming are formed. Furthermore, the surface current distribution graphs for the antennas under consideration are acquired. As a result, it is found out that antenna arrays with air-out dielectrics enable lowering the impact of mutual coupling on the beamforming and DOA-estimation features.