Time-domain analysis of closed structures singularities

In this paper, the singularity of closed structures when using time-domain magnetic field integral equation is analysed. This type of formulation is solely applicable to closed structures and it is tried to show the effect of the singularities existing at the internal resonant frequencies of the closed structure. The results of a closed sphere are compared with analytical solution to demonstrate the minor effect of such singularities. In order to avoid the late-time instabilities, the implicit method of moments is used to solve the resultant integral equations.