Mutual coupling compensation in uniform circular arrays with center element using a coupling matrix based on phase modes

By expanding the radiation characteristics into phase modes, a coupling matrix is constructed to compensate for mutual coupling in uniform circular arrays with a center element. Relying on a limited number of phase modes, this matrix fully describes the dependency of the receive and transmit characteristics on azimuth angle, for a given elevation angle and for arbitrary terminations placed at the different antenna ports. A sample dual band uniform circular array with center element illustrates the use of the coupling matrix for direction of arrival estimation