For the radio frequency equipments, there were many analytical studies using the FEM (Finite Element Method). Various methods have been approached to avoid sprious solutions. But, they have problems in computing time, formulation technique, programing and so on. At this time, we studied about the sprious solutions and successfully eliminated them with the new finite element taking into account the vector divergence conditions.
In this paper, the new finite element formulation which can eliminate the sprious mode is discribed. As an application, the resonance frequency of the magnetron cavity resonator is successfully calculated.