Effect of a ground plane perforation on far-field phase

A unit cell comprised of a circular aperture is modelled centered in the ground plane beneath a microstrip patch. A phase change of 82–86° is obtained at the patch resonant frequency in the far-field for a cell radius of 0.4L, where L is the resonant length of the patch. A stacked patch structure is investigated to maintain an adequate match at the resonant frequency of the unloaded patch. A phase change of 127° is reported with the stacked patch for a cell radius of 0.2L.