Synthetic aperture functions for arrays of stepped horns

A systematic procedure to reduce the computational effort (in terms of memory and computation time) is introduced for the full-wave analysis of corrugated or stepped rectangular horns/cavities open ended on an infinite ground plane. This procedure, based on the method of moments (MoM), consists of the construction of appropriate bass functions generated by solving the problem of one properly excited element in isolation. These functions , denoted by Synthetic Aperure Functions (SAF), being numerical solutions of an integral equation which represent magnetic field continuity, have the adequate contents of high-order waveguide modes that allow the proper storage of local reactive energy. They also include a good approximation of the correct edge behavior. The technique reveals a significant reduction of computation time with respect to an ordinary MoM solution, especially for large number of radiating elements.