A numerically stable transmission line model for multilayered Green's functions

The evaluation of a multilayered media Green's function (GF) in the spectral domain can be reduced to the analysis of a uniform transmission line (TL) circuit along the normal component (Michalski, K. and Mosig, J., IEEE Trans. Antennas and Propag., vol.45, p.508-19, 1997). In a practical situation, the computation of the GF requires many evaluations of this circuit by a transmission line model (TLM) (Michalski and Mosig, 1997; Chow, Y.L. et al., IEE Proc. Microwaves, Antennas and Propag., vol.145, p.85-91, 1998) which combines very different TL states (under cutoff, resonance, etc.). In addition, modern manufacturing techniques include components made of new materials and dimensions which commonly produces instabilities in a classical TLM analysis. The paper proposes a fast and accurate TLM algorithm to overcome this problem.