Optimal circular array design for direction finding

Circular antenna arrays are widely used in direction finding applications. In this study, circular arrays are designed by minimizing the Cramér-Rao Bound (CRB). Firstly, for a given number of antennas and a fixed radius, the conditions to minimize the average CRB and corresponding all closed form solutions are found. For each solution, ambiguity, which is a measure of probability of gross errors in direction finding operation, is analyzed and a procedure to find circular arrays with low ambiguity is proposed. Finally, the performances of the designed arrays are compared to the union of uniform circular arrays.