THE GENERALIZED TLM-BASED FDTD MODELING OF FREQUENCY-DEPENDENT AND ANISOTROPIC MEDIA

A generalization of the previously proposed transmission-line matrix ( TLM)-based finite-difference time-domain (FDTD) method is presented fo r modeling frequency-dependent and anisotropic media. The generalized scheme incorporates electric-and magnetic-flux densities in addition t o variable mesh sizes. Since it is in an FD form, modeling techniques developed for the conventional FDTD can be easily adapted into the pro posed TLM-based technique. In this paper, a modified z-transform techn ique for frequency-dependent media is implemented, and a two-dimension al (2-D) full-wave technique for guided-wave structures is developed. in all the FDTD computations, no conversions between the field quantit ies and TLM circuit parameters such as open-and short-circuited stubs are required.