Sparse Billboard and T-Shaped Arrays for Two-Dimensional Direction of Arrival Estimation

In two-dimensional direction of arrival (2D-DOA) estimation, planar arrays can estimate the elevation and azimuth angles simultaneously. However, many array topologies such as billboard, L-shaped, T-shaped, 2D nested suffer from mutual coupling that results small separation between physical sensors (antennas), which limits estimation capability sensor array. an attempt to reduce sensors, this article proposes sparse billboard T-shaped in number closely separated is significantly reduced. addition extending CRB for fourth order coarray, also derives closed-form expressions locations consecutive lags or uniform degrees freedom (uDOF), fourth-order difference coarray (FODC). Simulation demonstrate robustness proposed against coupling.