Further Results on the Zero Redundancy Sparse Arrays for DOA Estimation

It is known that the zero redundancy sparse arrays (ZRSA) explore the concept of sum and difference coarray (SDC). Both ZRSA-I and ZRSA-II are attractive options for the direction-of-arrival (DOA) estimation. The main property of these arrays is that they attempt to minimize the redundancy of lags between the sum coarray and the difference coarray. In this work, the performance of the ZRSA configurations is further improved in both degrees of freedom (DOF) and mutual coupling perspectives. In fact, the proposed arrays obtain the highest DOF among the state-of-the-art arrays. To perform that, the elements of ZRSA-II are shifted by a specific translation factor so that the overlapping of the sum coarray lags and the difference coarray lags further decrease. To reduce the mutual coupling, the elements of the array are placed in strategic locations. Simulation results validate the superiority of the proposed arrays over the other existing arrays.