The contour path finite difference time domain (CPFDTD) method has bee
n shown to give accurate results for curved metal structures. However,
the numerical stability of this scheme is not guaranteed and signific
ant skill is required to generate an appropriate grid. The authors pre
sent a modification to the two-dimensional CPFDTD method which ensures
stability and which permits simple generation of the locally distorte
d grid. The accuracy of the scheme is demonstrated through calculation
of the resonant frequencies of circular cylindrical resonators.