Transmission properties of a circular aperture array on a ground plane backed by a rectangular patch, etched on substrate, over each aperture

In the work of Shafari and Shafai (2009) a parametric study, using Ansoft HFSS, on the effect of aperture diameter on transmission properties of an array of apertures is performed. The unit cell included a centered circular aperture on a ground plane, where aperture diameter was swept over a wide range. The unit cell was chosen to have the same transverse dimensions as X-band waveguide, i.e. S_x = 22.86 mm, S_y = 10.16 mm. In this paper, the goal is to investigate the effect of placing a rectangular patch, etched on substrate, on top of the aperture in unit cell, thereby loading the aperture by a conducting patch.