On the nature of wire grid modelling for numerical solutions of electromagnetic problems

Wire grid modelling has been used successfully for solving radiation and scattering problems of complicated structures, but its mathematical basis remains unclear. In this paper, we prove mathematically that wire grid modelling is equivalent to the point-matching method with subdomain basis functions. Other questions arising from applications of wire grid modelling, such as the selection of wire radius based on the "same surface area rule" and difficulties in satisfying the boundary conditions are considered and explained based on this equivalence.