An iterative absorbing boundary condition using varying element orders

Iterative absorbing boundary conditions (ABCs) are a way of truncating the unbounded domain of an electromagnetic wave problem. They require repeated solution of the field problem, with the ABC updated each time. Here, the computational expense is reduced by solving with low-order finite elements (FEs) in the early iterations and progressively increasing the order. Results for the radar cross section (RCS) of the metallic and dielectric obstacles demonstrate that the approach is accurate and significantly reduces the computation time.