Direction of arrival estimation enhancement for closely spaced electrically small antenna array

Summary form only given. Direction of arrival (DOA) of a microwave signal is important for many commercial and military applications. Accurate DOA estimation technique with small system size is highly desirable. Electrically small antenna array with small spacing between any two adjacent antennas is attractive because of the compact size of thewhole system. The challenge is how to achieve high accuracy of DOA estimation under this circumstance.