A stable time domain boundary element method for the analysis of electromagnetic scattering and radiation problems

摘要

It is known that numerical electromagnetic techniques based on a time domain recursive solution of the electric field integral equation may exhibit instability phenomena induced by joint space-time discretization of the field equations. In this paper we address the above problem with specific reference to the evaluation of the electromagnetic scattering from petfectly conducting bodies of arbitrary shape. In particular, we analyze a specific formulation of the method of moments which relies on a triangular-patch geometrical model of the exterior surface of the scatterer and operates according to a marching-on-in-time scheme, whereby the surface current distribution at a given time step is evaluated as a function of the previous distributions. A heuristic stability condition is devised for the simulator, which allows us to define a proper time step, as well as a correct geometrical discretization, ensuring convergence of the numerical procedure. The stability condition is discussed and validated by means of a few working examples.