A theoretical model for dielectric resonators in whispering gallery mode for application in millimetre wave monolithic integrated circuits

Whispering gallery mode dielectric resonators have high quality factors, compatibility with MMIC´s and reasonable mechanical dimensions even at millimeter-wavelength frequencies. They have been used in filters, oscillators and power combiners. For practical use dielectric resonators must be coupled to a transmission line. In this paper a relatively simple mathematical model of the coupling between a dielectric resonator acting in WGE mode and a transmission line has been proposed. Rather than coupling in one plane, the concept of using an effective coupling length; as previously been used in conventional mode dielectric resonators; has been introduced in the analysis. Finally, measured quality factors are compared with our proposed model and they have found to be in good agreement