Whispering Gallery Mode Hemisphere Dielectric Resonators With Impedance Plane

The electrodynamic characteristics of a high-Q dielectric whispering gallery mode resonator in the form of a hemisphere positioned on an impedance plane were studied. The analysis of the anisotropic resonator was modeled using Maxwell equations and the impedance Leontovich boundary condition. The interaction coefficient A_S^j of the conductor and microwave field was determined using a frequency and field distribution of the j-type mode in the hemisphere resonator considering a perfect conducting plane. Results of the theoretical study and experimental measurements of the Teflon resonator frequency spectrum and Q factor are in good agreement. The results obtained are confirmed by calculations using Microwave Studio CST 2008. In the case of the sapphire hemispherical resonator with an impedance plane, comparison of the experimental and simulation results allows us to identify the H -type modes in the resonator and their electromagnetic field distribution. In such anisotropic hemisphere resonators, the quasi-TE modes are revealed. The modes are excited together with TE modes inherent to the isotropic resonator and they have an identical distribution of electromagnetic field.