An effective procedure for accounting for the mutual coupling between rectangular apertures in the design of nonuniform array antennas is discussed. The central element of the procedure is a two-dimensional interpolation scheme allowing the evaluation of the coupling admittance between arbitrarily located rectangular apertures based on 9 pre-computed values. The manner in which the interpolation strategy can serve a purpose in optimisation schemes for reaching certain radiation pattern or active reÁection coefÀcient design requirements is focused upon. The method's effectiveness is illustrated by examining the case of some medium-large nonuniform placements with demonstrated superior performance. The inclusion of the mutual coupling is shown to affect pronouncedly the performance predicted by means of the array factor, only. Indications on the computational costs of including the computational strategy in iterative optimisation schemes are also given.

A complete tool for analyzing the mutual coupling in nonuniform (interleaved) array antennas consisting of rectangular aperture radiators is discussed. It relies on deriving the coupling admittances between arbitrarily located apertures via a two-dimensional interpolation scheme. Realistic radiators are accounted for through their scattering matrix evaluated by means of full-wave analyses. The method yields accurate results while greatly reducing the computation time. Its validity is demonstrated against measurements done on a medium-sized, interleaved, nonuniform array of cavity-backed apertures.