Investigation of cavity-backed aperture antenna with single or stacked subreflector configurations

We use the combination of the integral equation and modal expansion method (IE/MEM) to study the electrical performance of the rectangular cavity-backed aperture antennas of irregular shapes. This technique is adopted since it has the advantage of reducing the three-dimensional problem to a two-dimensional one over the coupling surface. Consequently, the computational time and the memory requirement is reduced significantly. On the other hand, since the modal expansion is used to present the field inside the cavity, the solution is limited only to the rectangular cavity structure. The subreflector shape has direct effect on the radiation pattern and in particular the crosspolarized pattern.