A 4TH-ORDER IN-SPACE AND 2ND-ORDER IN TIME TLM MODEL

In this paper a new TLM model is presented for solving two-dimensional electromagnetic held problems. The new model possesses the same dispe rsion relation as a fourth-order in space and second-order in time cen tral-finite-difference algorithm, The stability criterion of the TLM m odel (given in terms of permissible values for the admittance of the p ermittivity stub) is provided. Investigation of the propagation charac teristics indicates the benefits of fourth-order spatial discretizatio n, especially for modelling dielectric media. The improved dispersive properties of the fourth-order models make them attractive candidates for the analysis of electrically large (and inhomogeneous) problems. T he scattering acid transfer events for the new model are presented as well as results from numerical experiments, The improved computational efficiency of the new fourth-order accurate model in terms of both me mory storage and computation time (as compared to the original second- order TLM algorithm) is demonstrated.