FDTD-how complex a problem can we solve?

Summary form only given. The finite-difference time-domain (FDTD) method is a straightforward solution approach for Maxwell´s equations that involves no linear algebra. Being a fully explicit computation, FDTD avoids the difficulties with linear algebra that limit the size of frequency-domain integral-equation and finite-element models to order (10/sup 6/) field unknowns. FDTD models with as many as 10/sup 9/ unknowns have been run. From a computational standpoint, there is no intrinsic upper bound to this number, except for the possibility of unacceptable error accumulation in the propagating numerical wave modes in the FDTD space lattice as the problem size increases indefinitely. This paper explores the potential impact of advances in computer capabilities and FDTD algorithms upon the maximum feasible size and complexity of three-dimensional FDTD electromagnetic wave models.