ADNAs: Sparse antenna array design strategies with the maximum inter-element spacing constraint

In this paper, two sparse antenna array (SAA) design strategies, entitled augmented dilated nested arrays (ADNAs), are proposed with the maximum inter-element spacing (IES) constraint for direction of arrival (DOA) estimation. Specifically, the proposed ADNA-I and ADNA-II rearrange the sensors of subarrays with IES (Formula presented) in the original dilated nested array to mitigate the mutual coupling effect and enhance uniform degrees of freedom (uDOFs). Furthermore, closed-form expressions are provided for characterizing the sensor locations, uDOFs and weight function for ADNA-I and ADNA-II. Numerical simulations indicate that, under strong mutual coupling (MC) scenarios, the proposed ADNA-I and ADNA-II possess pronounced superiority over competing SAAs.