On coupling electromagnetic fields and lumped circuits with TLM

The application of the transmission-line matrix (TLM) method to the modelling of the evolving electromagnetic field within a capacitor structure is considered in this paper. The experiment of Al-Asadi et al. [Electron. Lett. 30 (4) (1994)], consisting of the capacitor connected to a source and a resistor and modelling the current following an abrupt switch-on, is reconsidered. The effect of using finer TLM meshes and extending the mesh beyond the capacitor structure is studied. The outcome of replacing the abrupt switch-on by a smooth switch-on is also examined. The method employed in Al-Asadi et al. (loc. cite) for coupling the capacitor to the network, termed the current sources method is also used in this work. The practicalities of using this method and some of its effects are examined