Eigenmodes of microwave cavities containing high-loss dielectric materials

The numerical determination of the electromagnetic field eigenmodes of a microwave cavity containing regions of high-loss dielectric material is of technological importance to many areas, including high power microwave generation, particle accelerator design and microwave sintering of ceramic materials. This problem has proved problematic to numerical techniques, causing poor convergence and long computation times when highly lossy materials are present. The Jacobi-Davidson algorithm applied to this problem is shown to be capable of extracting a set of eigenmodes, even for the cases of degenerate eigenvalues and low ohmic-Q cavity modes. Details of the theory and numerical solution using 2-dimensional (planar circuit) and 3-dimensional electromagnetic operators will be presented.