A Mixed Numerical Technique for Fast Computation of Hybrid Modes Resonant Frequencies in Ring-Shaped Dielectric-Loaded Resonators

This paper presents an original approach to the computation of hybrid modes resonant frequencies of dielectric ring resonators into a cylindrical cavity. The method employs both 1-D FEM and mode-matching for evaluating the generalized scattering matrix at discontinuity between dielectric-loaded waveguide and empty waveguide; by suitably manipulating this matrix, a generalized admittance (or impedance) matrix characterizing the resonator is derived: resonant frequencies are then obtained looking for the zeros of the determinant of these matrices. The paper also reports examples of normalized design charts for the first hybrid mode (HEh 11) which have been realized using the proposed technique.