Application of the nonuniform FDTD technique to analysis of coaxial discontinuity structures

In this paper, we employ the nonuniform finite-difference time-domain (NUFD TD) technique to accurately model discontinues in complex coaxial configura tions, We take advantage of the azimuthal symmetry of the structure to redu ce the original problem into an equivalent two-dimensional one, and we do t his by projecting the three-dimensional Yee cell onto two-dimensional plane s. Numerical results are presented for various discontinuities to illustrat e the application of the method. We show that the NUFDTD technique yields r esults that are in excellent agreement with the mode-matching method.