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