Relation Between the Array Pattern Approach in Terms of Coupling Coefficients and Minimum Scattering Antennas

The well-known approach for the calculation of the radiation pattern of a finite array from the scattering parameters between the array feeding ports (coupling coefficients) is connected to the theory of minimum-scattering antennas (MS antennas) by making use of spherical mode expansions. It is shown how this approach for array radiation patterns involves an MS Antenna approximation in the first order of reflections (mutual coupling) between the elements in the array. For this purpose the generalized scattering matrix (GSM) formalism for a finite array in terms of spherical modes is used. Finally, the MS antenna theory is applied to estimate the radiation pattern of an array of waveguide-fed apertures.