Analysis of spurious modes in mixed finite element method for Maxwell's equation with E and H as variables

In this study the formulations of mixed finite element (FEM) method for Maxwell's equations with E and H as variables are given, and the appearance of spurious modes of this mixed FEM are discussed. Numerical experiments demonstrate that the spurious modes can be eliminated by choosing the interpolation degrees for E different from that for H. This non-spurious mixed FEM scheme can be utilized in both time domain and frequency domain, and it is very suitable for the future implementation of the discontinuous Galekin finite element method (DG-FEM).