A Two-Grid Vector Discretization Scheme for the Resonant Cavity Problem With Anisotropic Media

Application of the classical finite-element method (FEM) to the resonant cavity problem leads to nonphysical modes and expensive computational costs. In this paper, a new two-grid vector discretization scheme is presented for computing the resonant cavity problem with lossless anisotropic media in 2-D and 3-D. This scheme is based on the mixed FEM with the edge element, the shifted-inverse power method, and the Rayleigh quotient so that it cannot only successfully suppress all nonphysical modes but also significantly reduce the computational costs. In addition, this scheme is highly efficient for the microwave cavity filter and the open cavity problem. Several numerical results are provided to show that the scheme is reliable and efficient.