Subcell FDTD for Computing the Cutoff Frequency of the Waveguide Loaded with Electrically Thin Dispersive Layer

A novel method for computing the cutoff frequency of the waveguide loaded with the electrically thin dispersive layer is introduced. The proposed method is based on the subcell FDTD technique and Z transforms. The most significant feature of the proposed method is its ability to compute the cutoff frequency of the waveguide loaded with rather complicated dispersive layers having multiple pole pairs. The method is validated with several numerical examples making comparison with the exact results. Keywords: Cutoff frequency of the waveguide, Electrically thin dispersive layers, Subcell FDTD, Z Transforms.