Project:

Scattering at
Coated Dielectric Objects

Researcher(s): | Prof. Dr. R. Hiptmair |

Bogdan Cranganu-Cretu. ABB Corporate Research, Baden-Dättwil | |

Funding: | no external funding |

Duration: | 10/2003-10/2004 |

**Description.** We developed a new
variational direct boundary integral equation approach for solving the
scattering and transmission problem for dielectric objects partially
coated with a PEC layer. The main idea is to use the electromagnetic
Calderón projector along with transmission conditions for the
electromagnetic fields. This leads to a symmetric variational
formulation which lends itself to Galerkin discretization by means of
divergence-conforming discrete surface currents. A wide array of
numerical experiments confirms the efficacy of the new method.

The geometry considered in an numerical experiment [CCH04] was a metallic rectangular container filled with sea water. The upper part is partially covered with a metallic lid as can be seen in figure Fig. 1. The dielectric constant of the water was assumed to equal . This leads to a situation beyond the scope of the EFIE.

A convergence study on four meshes ranging from very coarse (471 unknowns) to fine (4858 unknowns) is reported in Fig. ( ). Obviously, away from any resonance frequencies, the solution on the coarse meshes is satisfactory already, whereas on a resonance frequency fine meshes yield significantly better results.

Plots of the electromagnetic field on the surface of the cube are presented in Figs. -. Field singularities at edges are conspicuous. A section of the transmitted field is shown in (Fig. for a wave number .