An Improved Absorbing Boundary Condition for Finite-Element Analysis

In finite-element simulations, absorbing boundary conditions (ABCs) are recognized as simple but useful techniques for domain truncations. However, the widely employed first-order ABC often encounters accuracy challenges, and the existing second-order ABCs are also limited in their handling of domain corners. This study proposes a novel ABC formulation, distinguished by its improved accuracy and versatility. It is developed by projecting field normal components onto auxiliary variables and implemented without the necessity of a smooth domain boundary. Numerical examples showcase the accuracy enhancement achieved with the proposed ABC over traditional ABCs and the applicability of the new ABC implementation for finite-element domains with nonsmooth boundaries.