Symmetric Displaced Coprime Planar Array for Two-Dimensional Direction-of-Arrival Estimation

Recently, sparse planar arrays have been developed to improve the 2-D direction-of-arrival (DOA) estimation performance by their superiorities in the degree of freedom (DOF), array aperture, and mutual coupling over uniform planar arrays. In this article, we devise a new sparse planar array, termed symmetric displaced coprime planar array (SDCPA), for estimating the 2-D DOAs. The SDCPA configuration consists of three sparse uniform rectangular arrays (URAs) with a certain horizontal and vertical displacement, implying that there are two bilaterally SDCPAs with one shared subarray. Under any number of sensors, the sensor positions of an SDCPA can be expressed in a closed form. We also derive the optimal displacement factors to achieve the maximum number of consecutive coarray lags, which can be analytically calculated. Compared with the conventional CPAs, the SDCPA configuration possesses a higher number of uniform DOFs and fewer mutual coupling effects. Numerical results demonstrate its superiority over several existing sparse planar arrays.