The New Possibilities of Superlans Code for Evaluation of Axisymmetric Cavities

The equation (1) is solved by the finite element method. We use four corner eight nodes isoparametric elements. Algebraic system of equations for node field values is produced by Galerkin method. To find several modes simultaneously in arbitrary spectrum domain, we use subspace iteration method with frequency shift. If the permittivity and permeability of lossy filling depend on frequency, the self-consistent problem is solved. The iteration is produced in the next way. The solution for fixed permittivity and permeability is used as an initial approach. Then for this frequency the new values of permeability and permittivity are chosen. Using this values of permittivity and permeability, we find the new frequency by the method of inverse iteration with frequency shift, which provides the effective separation of searched mode. We use the frequency of the previous iteration as a shift. As a rule, several iterations are enough to obtain the selfconsistent solution. Iterations are produced automatically, if a file with permittivity and permeability frequency dependencies is prepared. There are two versions of code for PC and VAX at present.