A fast calculation method for the receiving mutual impedances of uniform circular arrays

A fast and accurate method is introduced for the determination of the receiving mutual impedances of uniform circular arrays (UCAs) with omnidirectional antenna elements. By using the symmetry consideration for UCAs, the number of unknown receiving mutual impedances is reduced by at least 2(N-1) times of that by using a full characterization method. A further improvement of using only a single calibration signal coming from a single incident angle makes the new method much more efficient in facilitating the determination of the receiving mutual impedances of UCAs by either theoretical calculations or by an experimental measurement. Our simulation results and a direction-of-arrival (DOA) estimation example study demonstrate the efficiency and validity of the new method.