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

Reflection and transmission properties of a thin and lossy slab, surro unded by two homogeneous and lossless semi-infinite media, are analyti cally examined in the time domain. Arbitrary incidence angles of the i ncident, homogeneous and plane TEM-wave are allowed. The time-domain m ethod used allows arbitrary wave shapes. It is shown that reflection a nd 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 cas e where material properties of the two semi-infinite spaces are differ ent. Finally, the application of the developed surface impedance bound ary conditions in numerical simulations is shown.