Mutual coupling in a finite planar array with interelement holes present

The mutual coupling in a finite planar array with interelement holes present was considered. A computer program designed to study mutual coupling between rectangular waveguides was modified to include coupling between elements of different sizes. This modified program was used to study the problem of widely spaced rectangular waveguides that form smaller rectangular holes in the ground plane. Comparisons with experimental data confirmed the validity of the model. Tests run at various hole sizes showed that holes that are much smaller than their cutoff size have little effect on the coupling. For the rectangular-hole case, hole widths of less than half the cutoff width of the dominant mode had little effect.