Cut-off and phase constants of partially filled axially magnetized, gyromagnetic waveguides using finite elements

A three-component vector finite-element formulation for modeling the propagation characteristics of partially filled, axially magnetized, gyromagnetic waveguides is described. Covariant-projection elements have been used to avoid spurious modes, and periodic boundary conditions have been implemented to improve numerical efficiency. The classic quadratic functional derived from the vector, curlcurl, magnetic field equation is suited to evaluating the cut-off planes of gyrotropic waveguides. A known field transformation is used to reformulate the functional in a form convenient for calculating phase constants. Cut-off and phase constant solutions are presented for both fully and partially filled, longitudinally magnetized, ferrite-loaded waveguides.>