Numerical studies of diffraction by 2-D homogeneous and inhomogeneous dielectric wedges

Abstract

Analytical expressions based on uniform theory of diffraction (UTD) are widely used in ray-tracing simulation tools for the diffraction problem. Although these theories predict the fields accurately in the far-field region for simple problems, it is difficult, if not impossible, to extend the analysis to find diffraction coefficients for wedges composed of dielectric and imperfectly conducting materials. In fact, the classical problem of diffraction from an infinite lossless dielectric wedge has not been solved analytically. In the past, we demonstrated the successful application of the FDTD method to numerically obtain diffraction coefficients for an infinite PEC wedge. In this paper, we use the FDTD method in a similar approach in order to find the electromagnetic field in the shadowing region of the inhomogeneous wedge. We further extend the FDTD approach to analyze parameter sensitivity for the diffracted fields from 2-D inhomogeneous material wedges representing practical cases, such as corners of different buildings with different type of inhomogeneities. This approach, in principle, can be extended to calculate the power in the shadowing region in three dimensions.