Slotted-disk sapphire quasi-optical resonator with conducting endplates

Quasi-optical dielectric resonator (QDR) in a form of slotted sapphire disk sandwiched between conducting endplates (CEP) is proposed and studied in Ka-band. The resonator is excited on whispering gallery modes. Mode identification of the slotted disk resonator with CEP is carried out. The measurement data are compared with simulated frequencies and Q-factors of the resonator with a copper sample under test and CEP. The calculation results are obtained using CST Microwave Studio software. The proposed and studied sapphire QDR is a promising basis for high accuracy measurements of small conducting samples (unconventional superconductors e.g. pniktides and HTS cuprates, nanotubes etc.) in millimeter wavelength range.