A comparative study of infinite elements for two-dimensional electromagnetic scattering analysis

Recently, a new type of infinite element was proposed as an accurate and efficient mesh truncation method for the finite element analysis of open-region acoustic scattering (D.S. Burnett, J. Acoust. Soc. Am., vol. 96, no. 5, pp. 2798-2816, 1994; D.S. Burnett and R.L. Holford, Comput. Meth. Appl. Mech. Engrg., vol. 158, pp. 117-141, 1998; J. J. Shirron and I. Babuska, ibid., vol. 164, pp. 121-139, 1998; J. Shirron and S. Dey, ibid., vol. 191, pp. 4123-4139, 2002). These infinite elements are based on the radial expansion of the scattered field and are used to model the scattered field outside a separable surface characterized by a constant radial coordinate (such as a spherical or a spheroidal surface in three dimensions). In this paper, two-dimensional (2D) elliptic infinite elements are formulated and implemented for the finite element analysis of 2D time-harmonic electromagnetic scattering and their performance is studied by comparison with the finite element solution using conventional absorbing boundary conditions (ABCs). Numerical results are presented to demonstrate that the new type of infinite elements is indeed more accurate than both the first- and second-order ABCs.