Enhanced CACIS configuration for direction of arrival estimation

In this letter, an enhanced coprime array with compressed inter-element spacing is designed for direction of arrival estimation. First, we analyse and conclude that the 0th sensor redundant consecutive lags, thus it rearranged to negative part obtain spacing. Then, on basis discussing effect shift difference co-array, number unique lags range are derived. Theoretical properties show closed-form expressions similar, while more can be generated from latter. Moreover, larger slightly alleviate mutual coupling. Numerical examples verify advantages in estimation over configuration other arrays.