An exact absorbing boundary condition for 2D Helmholtz equations in layered media

Abstract. In this paper we will present an exact absorbing boundary condition for solving 2-D exterior Helmholtz equation in a unbounded domain. The proposed boundary condi-tion is based on the Dirichlet-to-Neumann mapping for the exterior strips surrounding the boundary of the rectangular computational domain. After the variables along the half-line interfaces are eliminated in terms of the solutions on the computational boundary, an exact boundary condition is obtained for the formulation of a finite element method of the exterior Helmholtz problem over the finite computational domain. 1