Approximate approach to the design of shielded dielectric diskresonators with whispering-gallery modes

An analytical method is presented for calculating the resonant frequency and the Q-factor of shielded dielectric disk resonators excited in whispering-gallery modes. The method is based on a single-mode representation of electromagnetic fields in partial regions of the resonator. For high order modes with high degree of energy concentration in the dielectric this method gives a good agreement with experimental results obtained for different sapphire disks at both room temperature and cryogenic temperatures