Scattering of dielectric cylinders using a time domain approach

摘要

In recent years, time-domain analysis has received much attention with the importance of transient analysis mainly in EMC/I problems. If one restricts to arbitrary geometries, numerical methods are obviously the most appropriate. Moment-method (MoM) [1] was first applied to the scattering of inhomogeneous objects with arbitrary shape, in both frequency and time domains. This method requires some mathematical preamble which is rather involved. However, it has the advantage of employing a minimum number of unknowns since, by using an integral equation approach, the scatterer only has to be subsectioned rather than the all space. As a result, there is no need for imposing artificial boundary conditions. On the other hand, simpler methods such as finite-difference time-domain technique (FT-DT) and, more recently, transmission-line matrix method (TLM) have been proposed for open field problems [2,3]. Both methods are mathematically less involved but suffer from the fact that, since the all space must be subsectioned, artificial boundary conditions must be imposed to give a limit to the size of the problem. There are some difficulties if these boundaries are not located where field values or expressions are known, in which case the conditions become rather involved and complicate the algorithm. However, both methods can handle nonlinear, time-varying and even, under certain conditions, nonisotropic problems with relatively little mathematical complications.