CHARACTERIZATION OF MICROSTRIP DISCONTINUITIES USING CONFORMAL MAPPING AND THE FINITE-DIFFERENCE TIME-DOMAIN METHOD

Microstrip discontinuities are analyzed using Wheeler's waveguide mode l and the finite-difference time-domain (FDTD) method. Wheeler's model employs a conformal transformation to convert a microstrip into an en closed waveguide structure. This permits the mapping of a discontinuou s microstrip into a discontinuous, but enclosed, waveguide. The enclos ed waveguide eliminates the difficulties usually associated with analy sis of an open domain geometry. The FDTD technique is then used to cal culate the scattering coefficients of the discontinuous waveguide. The features of this approach are: 1) it yields a smaller computational d omain than that required to analyze the untransformed geometry; 2) it yields results over a band of frequencies; and 3) it is simple to impl ement. Results obtained using this scheme show good agreement with pre viously published results.