Finite-Difference Time-Domain Methods

Abstract

Publisher Summary This chapter discusses finite-difference time-domain (FDTD) methods. During the 1970s and 1980s, a number of researchers realized the limitations of frequency-domain integral-equation solutions of Maxwell's equations. This led to early explorations of a novel alternative approach: direct time-domain solutions of Maxwell's differential (curl) equations on spatial grids or lattices. FDTD and related space-grid time-domain techniques are direct solution methods for Maxwell's curl equations. These methods employ no potentials. Rather, they are based upon volumetric sampling of the unknown electric and magnetic fields within and surrounding the structure of interest, and over a period of time. For simulations where the modeled region must extend to infinity, absorbing boundary conditions (ABCs) are employed at the outer lattice truncation planes, which ideally permit all outgoing wave analogs to exit the region with negligible reflection. Phenomena such as induction of surface currents, scattering and multiple scattering, aperture penetration, and cavity excitation are modeled time-step by time-step by the action of the numerical analog to the curl equations.