Use of lossless transmission-line segments and shunt resistors for TLM diffusion modelling

In diffusion modelling by means of the transmission-line matrix (TLM) method, a nodal arrangement of using lossless transmission-line segments and series resistors is almost exclusively adopted and is currently considered as a standard approach. In this paper, the use of shunt resistors instead of series resistors is shown to represent an equally valid configuration. As a starting point, we have derived the telegrapher's equation in its most general form for TLM modelling of diffusion processes. A general algorithm based on the shunt-resistor TLM model for implementing a numerical solution of the diffusion equation in multiple dimensions is given. Fundamental analysis and calculated examples confirm that the alternative shunt-resistor configuration does not exhibit the unwanted absorption effects suggested by a recent paper (Internat. J. Numerical Model.: Electronic Networks, Devices and Fields 2002; 15:261). Copyright (C) 2003 John Wiley Sons, Ltd.