Computation of the Smallest Positive Eigenfrequencies of Resonant Cavities with Freely Available Parallel Solvers

This work addresses the numerical solution of the differential cavity problem arising from Maxwell equations, by means of the finite-element method (FEM). This procedure presents the well-known problem of spurious modes: solutions satisfying the final algebraic problem but not the original differential equation. Among the proposed remedies, the better alternative seems to be the use of vector basis functions in the finite-element scheme (Nédélec-type elements). With this approach, the discretization of the weak formulation yields the following eigensystem [ ] 0~20 = − tEBA κ (1) where the eigenvalue i