Moment method model of a slot immersed in a planar array of waveguide slot radiators

A moment method analysis applied directly to a planar distribution of shunt slot radiators fed by an array of rectangular waveguides is described. The method intrinsically accommodates both the internal and external mutual interactions between the radiators, and the influence of these interactions on the resonance characteristics of slots embedded within a typical slot array is explicitly demonstrated. Low height and dielectric-loaded waveguide arrays are also examined and in these cases it is observed that additional care must be exercised in the selection of a representative basis function series to model the slot field distribution. Also, by employing entire domain basis functions the processor time demanded by these calculations, which are computationally intensive even for relatively small numbers of slots, can be substantially reduced. Computational efficiency gains of this description are essential if the procedure described is to have a real impact on the development of computer aided design packages for slotted-waveguide array antennas.