Circuit Model for Extraordinary Transmission Through Periodic Array of Subwavelength Stepped Slits

In this paper, two circuit models are proposed for analytical investigation of extraordinary transmission through periodic array of subwavelength stepped slits in a thick metallic plate. A cascade model is first developed and then a stub model is suggested for cases that the cascade model is not accurate. The parameters of the proposed circuits are given by closed-form expressions. Both symmetric and asymmetric stepped slits are considered.