Accuracy analysis of the nonrigorous second-order absorbing boundary condition applied to large curved finite elements

We investigate the accuracy of the nonrigorous symmetric second-order absorbing boundary condition (ABC) implemented in the higher order large domain finite element method (FEM) technique for electromagnetic analysis in the frequency domain. The electric field is expanded using edge based curl-conforming polynomial basis functions and geometrical modeling is done by curved hexahedral finite elements. The numerical examples show that radar cross section (RCS) of a benchmark scatterer is predicted more accurately when the divergence term is included (although not rigorously) in the computations. Performance of the implemented second-order ABC is compared with the first-order ABC and the rigorous second-order ABC.