SPURIOUS FIELDS IN TIME-DOMAIN COMPUTATIONS OF SCATTERING PROBLEMS

In this paper, two-dimensional (2-D) electromagnetic scattering proble ms with a time-periodic incident field are considered. The scatterer i s a perfect conductor, and an artificial boundary condition is used, T he large-time behavior of solutions, depending on (divergence-free) in itial conditions, is characterized, It turns out that in addition to t he expected time-periodic solution, the limiting solution may also con tain a spurious stationary field, The source of the stationary field i s explained and equations describing it are obtained, Several avoidanc e strategies are discussed and numerical comparisons of these techniqu es are given.