2D Fractal Based Sparse Array with Reduced Mutual Coupling for Direction of Arrival Estimation

This paper proposes a novel 2D fractal based sparse array (FBSA) to address the challenges of mutual coupling in direction of arrival (DOA) estimation. Leveraging the inher-ent self-similarity of fractal geometries, the proposed array achieves a hole-free co-array structure with large degrees of freedom (DOF), enabling the detection of more sources than sensors. The systematic element distribution of this array reduces mutual coupling effects. It improves the performance in terms of root mean square error (RMSE) for DOA estimation. The comparative analyses with conventional arrays, including uniform rectangular arrays (URA), nested arrays (NA), and Hourglass arrays (HA), demonstrate the superiority efficiency of the proposed design, larger aperture, and reduced mutual coupling. The simulated results validate the enhanced performance of the 2D FBSA in various scenarios, making it a promising candidate for modern radar, sonar, and wireless communication systems.