A rigorous analysis of dielectric ring resonators loaded in waveguide or microstrip line structure

A rigorous mode matching technique is used to analyze dielectric ring resonators loaded in a waveguide or microstrip line structure. Variations of the resonant frequencies for several lowest order modes with the structures´ parameters are presented. Analysis shows that increasing the inner concentric hole diameter changes the TE/sub 01/ mode resonant frequency by less than 1%, but increases the spurious mode free region by greater than 80% compared with the dielectric rod resonator. Two-dimensional (2D) electric and magnetic field line patterns and 3D field intensity distributions of the ring resonator are plotted, which provide valuable information on mode excitation, coupling, and suppression.<>