Zero-Redundancy Sparse Array Configuration Design Based on Sum-Difference Coarray

In this letter, we present a novel strategy for designing zero-redundancy arrays exploiting the concept of the sum-difference coarray. This approach aims to eliminate redundant lags between the difference and sum coarrays, resulting in a more efficient array design. Consequently, we introduce two new sparse array configurations, named Zero-Redundancy Sparse Array (ZRSA-I and ZRSA-II), for direction-of-arrival (DOA) estimation. These arrays have been proven to possess the zero-redundancy property and offer more uniform degrees of freedom (uDOFs) compared to many existing sparse arrays. Furthermore, we propose the Sum-Difference Translation Invariance Criteria (SDTIC) to mitigate the mutual coupling (MC) effects in the arrays. Theoretical propositions and simulation results confirm the exceptional performance of the proposed ZRSAs, highlighting their potential for enhancing angle resolution and estimation accuracy.