Magnetic current formulation for periodically loaded slots

A novel adaptation of the Wait-Hill formulation is proposed for the analysis of plane wave scattering from periodically loaded orthogonal slots. For the case of vertical slots loaded with infinitesimal lumped elements, the formulation leads to a novel exact analytical expression for the fundamental harmonic current amplitude. In addition, the formulation is shown to provide insight into lumped-element loaded slot miniaturised frequency selective surfaces.