New infinite elements for a finite element analysis of 2D scattering problems

Two new formulations of infinite elements are proposed. These elements in combination with the conventional finite elements yield coupled finite element formulations for 2D scattering problems. The first formulation works for any shape of the finite element region, while the second one has been developed for a rectangular outer boundary. In comparison with the previous infinite elements, the present infinite elements are constructed in such a way that simple expressions have been obtained for their element matrices. As a result of this, no formula for numerical quadrature over the infinite region is necessary and the infinite elements can easily be incorporated into standard finite element codes. Two numerical examples are given.