A new variational formulation, free of spurious modes, for the problem of loaded cavities

The authors propose a symmetrical approach to the computation of microwave fields in loaded cavities, which treats the electric field and the magnetic field equally, with two interesting features: spurious modes are avoided, and, as a by-product of the computation, an error estimate is obtained that can be used for adaptive mesh refinement. A numerical illustration, where edge elements have been used to solve a standard problem (dielectric cube inside a box), is given