Mutual coupling in non-uniform array antennas — An effective recipe

An effective method for estimating the mutual coupling in finite, arbitrary arrays of rectangular waveguide apertures is discussed. It relies on evaluating the admittance matrix relating rectangular waveguide modes, its entries being computed by means of an interpolation strategy with demonstrated accuracy. The method's strength is demonstrated by means of a twofold numerical experiment: (i) the estimation of the mutual coupling's effect on the scanning performance of two relatively large, (non-)uniform arrays and (ii) the estimation of the coupling between two large, interleaved, non-uniform sub-arrays representing the transmit and receive antennas of a frequency-modulated, continuous wave radar system.