TIME-DOMAIN CALCULATIONS OF THE REFLECTION AND TRANSMISSION PROPERTIES OF A THIN AND LOSSY SLAB

Reflection and transmission properties of a thin and lossy slab, surrounded by two homogeneous and lossless semi-infinite media, are analytically examined in the time domain. Arbitrary incidence angles of the incident, homogeneous and plane TEM-wave are allowed. The time-domain method used allows arbitrary wave shapes. It is shown that reflection and transmission coefficients exist for thin slabs. From the reflection coefficients we develop surface impedance boundary conditions for the use in FDTD-method. Subsequently, the results are expanded to the case where material properties of the two semi-infinite spaces are different. Finally, the application of the developed surface impedance boundary conditions in numerical simulations is shown.