# Scattering Analysis by a Stable Hybridization of the Finite Element Method and the Finite-Difference Time-Domain Scheme with a Brick-Tetrahedron Interface

**Electromagnetics**(1532-527X ). Vol. 28 (2008), 1-2, p. 3-17.

[Artikel, refereegranskad vetenskaplig]

We present scattering computations performed with a newly developed stable hybridization of the finite element method (FEM) and the finite-difference time-domain (FDTD) scheme, which is based on Nitsche's method. This hybrid has not been tested on scattering problems previously, and here we compute the radar cross-section (RCS) for three different targets: (i) the perfect electric conducting (PEC) sphere, (ii) the NASA almond, and (iii) a generic aircraft called RUND. In order to assess the discretization errors associated with the hybrid, we provide comparisons with established results and techniques: (i) the Mie-series for the PEC sphere, (ii) the method of moments (MoM) implemented in the commercial code FEKO, and (iii) a stable FEM-FDTD hybrid that exploits pyramids and a curl-conforming representation of the electric field. The bistatic RCS for the PEC sphere shows second order convergence towards the analytical solution and a relative error of 2% is achieved for about 20 points per wavelength. The NASA almond has a low monostatic RCS in its horizontal plane, which makes it a good benchmark problem for scattering computations. It features a sharp tip and, as a consequence, the order of convergence for the RCS is lowered. Given a careful convergence study for the NASA almond, we achieve a highly accurate monostatic RCS by means of extrapolation and this result is state-of-the-art in the open literature.

**Nyckelord: **electromagnetics, finite element method, FDTD, hybrid techniques, scattering analysis

*(Special Issue: Selected papers from the 5th International Workshop on Finite Element Methods for Microwave Engineering)*

Denna post skapades 2007-10-16. Senast ändrad 2016-07-22.

CPL Pubid: 54225