Analytical design of quasi-closed subwavelength electromagnetic rectangular resonators using stacks of dielectric–plasmonic bilayers

Abstract

We show that quasi-closed subwavelength electromagnetic rectangular resonators can be constructed using stacked dielectric-plasmonic bilayer structures, in an analogy to the dielectric resonators formed by materials with large permittivity commonly seen in microwave engineering. We establish an analytic framework for designing such subwavelength resonators by providing formulas for calculating the resonant frequency and the radiation/ material loss Q-factors of the fundamental mode. The provided analytic formulas yield accurate results when compared with the numerical simulations for a broad range of design parameter sets. The proposed stack resonator in principle can be made arbitrarily small and, in the absence of material loss, can have Q-factors larger than 10 5 .