THE ANALYSIS OF GENERAL 2-DIMENSIONAL PEC STRUCTURES USING A MODIFIEDCPFDTD ALGORITHM

The use of the contour path finite difference time domain (CPFDTD) met hod with locally distorted contours has been shown to give accurate re sults for curved metal structures. However, the numerical stability of this scheme is not guaranteed and significant skill is required in or der to generate an appropriate grid. In this contribution, we present a modification to the CPFDTD scheme which ensures stability and give a step-by-step procedure for simple generation of the distorted grid. E xamples are presented to demonstrate that the modified scheme yields r esults superior to those obtained using the standard staircased finite difference time domain (FDTD) approach. Example geometries are cylind rical cavities having complex cross-sections with smooth surfaces and right-angle bends. The accuracy of the method is demonstrated by compa rison to analytical results where available.