Enhanced Dilated Nested Arrays With Reduced Mutual Coupling for DOA Estimation

In sparse linear array (SLA) design, mutual coupling (MC) is a nonnegligible metric, while both MC effects and lower degrees of freedom (DOFs) can reduce the accuracy of direction-of-arrival (DOA) estimation. To mitigate the MC effect and achieve more unique DOFs, we propose two novel enhanced dilated nested array (EDNA) configurations, named EDNA-I and EDNA-II. In contrast to most advanced SLA configurations, the proposed EDNA-I and EDNA-II have fewer sensor pairs at smaller separations and thus have better robustness to MC effects. In addition, their sensor locations and DOFs can be derived as simple explicit expressions. Theoretical proofs and numerical simulations show that the proposed EDNA-I and EDNA-II have superior performance in terms of DOFs and weight function and also effectively suppress the MC effect, which in turn exhibits better DOA estimation performance in the presence of MC.