Modeling of inhomogeneous dielectric layers using TLM cuboid condensed node

This paper describes a modification of the transmission line matrix (TLM) method for numerical analysis of multi-dielectric layer structures by means of the 3D cuboid condensed node. An interface scattering algorithm is applied to properly represent the impedance step across the interface. A parallel plate resonator with two dielectric layers is analyzed with the cuboid scheme, and the results are compared with theoretically accurate values as well as results obtained with traditional stub-loaded TLM. The comparison clearly indicates that the cuboid cell is more flexible and more accurate than the stub-loaded scheme.