Modeling of discontinuities in microwave and millimeter wave integrated circuits using the curvilinear finite difference time domain approach

Describes a full-wave approach based on the curvilinear finite-difference time-domain (FDTD) algorithm for accurate modeling of discontinuities in microstrip lines that do not conform to the Cartesian coordinate system. The use of the curvilinear FDTD approach circumvents the staircasing problem that arises in the transmission line matrix (TLM) method as well as in the conventional FDTD approach based on the Yee-grid, and, consequently, makes it possible to accurately model arbitrary geometries without the use of a very fine mesh. The curvilinear FDTD method is more accurate than other proposed FDTD approaches or nonorthogonal grids; this superior accuracy is accomplished by transforming Maxwell´s equations from curvilinear space into a regular, rectilinear domain.<>