Numerical study of reflection and transmission coefficients for different inhomogeneous walls

Analytical expressions such as Fresnel reflection and transmission coefficients have been extensively used in most of the ray tracing simulation tools for the last few years. Although these tools predict the field accurately for simple homogeneous wall structures, it is difficult if not impossible, to extend such an analysis to find reflection and transmission coefficients for walls composed of dielectric and imperfectly conducting materials. In the past we demonstrated the successful application of the finite difference time domain (FDTD) method to numerically obtain reflection and transmission coefficients for pure homogeneous layered walls. We also compared measurements with the FDTD method for a certain type of inhomogeneous wall with satisfactory results. In this paper we further extend the FDTD approach to analyze the transmitted and reflected fields from 2-D inhomogeneous walls which represent practical wall structures, in order to identify the importance of the various parameters such as thickness, permittivity, and presence or absence of metallic rebars.