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ii For electromagnetics problems involving complicated source patterns, scattering objects, and inhomogeneous background media, analytical solutions to electromagnetic field solutions are usually not available. For these cases, numerical solutions are desired. Of the various numerical techniques available, the finite difference time domain (FDTD) method is emerging as the most popular technique due to its conceptual elegance and the completeness of the results it produces. Though FDTD has existed since it was first proposed by Yee in 1966 it has only risen to prominence in recent years as the computer industry has made it possible and cost-effective to handle FDTD's significant memory requirements. Our group at Northeastern University uses a Fortran-based FDTD code developed and placed on the public domain by the Luebbers group at Pennsylvania State University. Since its adoption by our group, it has been used by several group members to solve various electromagnetics problems and has also been extended by several group member