Increasing the Q-factor of Thin Planar Dielectric Resonators with Whispering Gallery Modes

The new design of dielectric resonators (DRs) formed by an ultra-thin dielectric disk placed between two conductive surfaces are presented. The possibility of the whispering gallery modes (WGMs) excitation in the thin planar DRs of Ka-band is considered. It is shown that WGMs can be excited in thin planar DRs whose height is much less than the operating wavelength. The spectral and energy characteristics and distribution of the WGM resonant fields with different azimuthal indexes were investigated. It is shown that the behaviour of spectral and energy characteristics of the thin planar DR depends from the design features of the planar DR. The insertion of the small air gap between conductive surfaces and flat surfaces of the thin dielectric disk leads to the significant increasing the unloaded Q-factor of thin planar DRs. The dielectric losses and losses in conductive surfaces with finite conductivity are decreased in this case. Increasing the unloaded Q-factor more than 4 times is obtained.