applying variations of permeability and permittivity in isotropic and anisotropic medias by using hybrid nodes in transmission line matrix method

in this paper two nodes to model isotropic and anisotropic media in transmission line matrix method (tlm) are presented. by using these two nodes, the permeability and permittivity of an anisotropic media can be modeled simultaneously. another application of these nodes is in modeling media with permittivity and permeability less than one. in the conventional 2 dimensional tlm, the stubs representing permittivity and or permeability get negative characteristic impedances, which in turn cause instability in the computation. studying the two suggested nodes, called the stub node and the hybrid node, respectively, shows the hybrid node can best model the simultaneous variations of permeability, permittivity of the isotropic and non isotropic media.