A Graded Mesh FD-TD Algorithm for Eigenvalue Problems

This paper describes the realization of a graded mesh for the FD-TD algorithm, and its application to three-dimensional eigenvalue problems. Eigenfrequencies of resonant structures can be obtained via Fourier transform exactly as with the uniform mesh FD-TD algorithm. However, the graded mesh leads to considerable CPU time reduction while its accuracy is comparable to that of the uniform mesh algorithm. Applications include planar and quasiplanar circuit structures.