Eigenvalue analysis in anisotropically loaded electromagnetic cavities using `edge´ finite elements

The eigenmodes in an arbitrarily shaped, electromagnetic (EM) cavity loaded with an anisotropic material are computed using linear tetrahedral edge elements and curvilinear hexahedral edge elements. The permeability tensor is assumed to have off-diagonal entries (gyromagnetic), and the permittivity and conductivity tensors are diagonal (typically for composite materials). Therefore, the divergence-free condition is not always satisfied inside a finite element. Yet, the procedure is found to yield good prediction of the lower resonant frequencies, and no spurious modes are encountered in this range of interest. In the examples considered, numerical solutions are consistent with quasi-analytical solutions