The Finite-Difference Time-Domain (FD-TD) Method for Electromagnetic Scattering and Interaction Problems

This paper summarizes the formulation and recent applications of the finite-difference time-domain (FD-TD) method for numerical modeling of electromagnetic scattering and interaction problems. One of the goals of this paper is to demonstrate that recent advances in FD-TD modeling concepts and software implementation, combined with advances in computer technology, have expanded the scope, accuracy, and speed of FD-TD modeling to the point where it may be the preferred choice for structures that cannot be easily treated by conventional integral equation and asymptotic approaches. As a class, such structures are electrically large, and have complex shapes, material compositions, apertures, and interior cavities. The discussion is highlighted by a succinct review of recent FD-TD modeling validations and research frontiers in radar cross section, coupling to wires and wire bundles in free space and cavities, scattering from surfaces in relativistic motion, inverse scattering, supercomputer and mini-supercomputer software, and radiation condition theory. The paper concludes with a summary of the strong and weak points of FD-TD, and guidelines concerning when FD-TD should (or should not) be applied to high-frequency electromagnetic modeling problems.