Analysis of general 3-D PEC structures using improved CPFDTD algorithm

The contour path finite difference time domain (CPFDTD) method, employing locally distorted integration contours, has been shown to give accurate results for curved three-dimensional metal structures. The numerical stability of this scheme is not, however, guaranteed and significant skill is required to generate an appropriate grid. The authors present a modification to the three-dimensional CPFDTD method which ensures stability and which permits simple generation of the locally distorted grid. The accuracy of the scheme is demonstrated through the calculation of the resonant frequencies of circular cylindrical and spherical resonators