Application of edge variable finite element methods in the design of RF cavities

This paper presents a finite element method for calculating resonant frequencies for a arbitrary three dimensional cavities. Firstly traditional nodal methods are considered and the reason for their failure in modelling high frequency fields. An edge element formulation and its solution of the problems of spurious modes and modelling of re-entrant corners is presented. With the aid of realistic cavity designs, the strengths of the finite element approach is illustrated, along with some disadvantages in present eigen value extraction techniques.