Computation of coupling between whispering gallery mode dielectric resonators and a microstrip transmission line

Whispering gallery mode dielectric resonators have high quality factors, compatibility with microwave integrated circuits and reasonable mechanical dimensions even at millimeter wavelength frequencies. For practical use dielectric resonators must be coupled to an external transmission line. A simple mathematical model of the coupling between a dielectric resonator acting in WGE mode and a transmission line is proposed. Finally, measured quality factors are compared with the proposed model