A hybrid coordinate scheme for enhancing the finite-difference time-domainmethod

In this paper, we present a hybrid coordinate FDTD scheme, in which we inse rt a local conformal coordinate system which conforms with the scatterers i n a Cartesian coordinate system, when there exists a nonrectangular scatter er in the Cartesian coordinate system. We propose a new interpolation schem e in the overlap region to achieve low reflection from the interface betwee n the built-in and Cartesian regions. The numerical experiment demonstrates that this scheme has a significant improvement in the staircasing approxim ation. (C) 2001 John Wiley & Sons, Inc.