Rectangular Waveguide Loaded with a Dielectric Slot in a Thick Metallic Shield

Abstract

Resonant transmission through a dielectric-loaded slot in a thick conducting diaphragm embedded in a rectangular waveguide is modeled using an analytical approximation based on the slot being small compared to a free space wavelength. Image theory relates this problem to a metasurface consisting of an array of such slots. We demonstrate the existence of ordinary (Fabry-Perot) transmission resonances associated with the fundamental mode of the slot, as well as extremely narrow-band (Fano) resonances involving the higher-order modes in the slot. The theoretical predictions are confirmed through full-wave numerical simulation and by experimental measurement.