Multi-scale modelling and simulation in electromagnetics

Research Staff: Konrad Biwojno, Phillip Sewell, Christos Christopoulos and Yafang Liu

Konrad Biwojno's PhD is funded by the Engineering and Physical Sciences Research Council (EPSRC), UK

Modelling for EMC involves dealing with systems that are both electrically large and yet contain small-scale features that significantly affect the overall behaviour. One recurring illustration of this is the inclusion of thin wires in simulations of large-scale objects where a significant volume of empty space must be modelled. While in principle techniques such as fine meshing and multi-gridding are possible, in practice these methods result in excessive storage and computational time.
In this project a non-standard node is being developed that allows an arbitrary number of arbitrarily placed thin wires to be modelled within one numerical cell. The backbone of this technique is a set of local analytical solutions for the fields in the vicinity of the multiple wires and the relationship between the tangential and electric fields on the surface of the node. This information allows the embedded node to be interfaced with the adjacent cells, yielding an algorithm that is both explicitly stable and conservative as well as incurring only a minor computational overhead. Further generalisation to other fine objects and micro-structured materials as well as the 3-D case is also being investigated. The Transmission Line Modeling (TLM) method was chosen as a firmly established numerical technique for simulating EM field in a wide range of application areas.

The example below shows the multi-wire mode, where an arbitrary number of fine features, per TLM cell, are analytically solved before mapping directly into a coarse mesh system.