Plane-wave illumination for the TLM method using a partial Huygen's surface

An efficient solution to the problems associated with plane wave illumination of a scattering body in a TLM mesh, initially presented by Porter and Dawson (see Electronics Letters, p.1683-1884, 1992) is explained. This has applications in determining the effect of electromagnetic interference (EMI) on structures ranging from aircraft to equipment housings. The equivalence of the solution to a partial implementation of the Huygen's surface (used in the time-domain finite difference (TDFD) method) is outlined. The method allows the use of considerably smaller TLM meshes for problems excited with a plane wave source than previously possible. The method uses the TLM mesh itself to generate the (equivalent of) retarded surface currents for the Huygen's surface. This gives automatic compensation for any dispersion in the mesh. The method is therefore suitable for problems using a graded mesh without further modification. >