Resonant frequency and quality factors of a silver-coated λ/4 dielectric waveguide resonator

Resonant frequency, radiation loss, conductor loss, and dielectric loss of a silver-coated lambda/4 dielectric waveguide resonator are investigated. Leakage of the EM field from the open-end face of the resonator is the only source of radiation, which also affects the resonant frequency. New theoretical expressions are devised to calculate resonant frequency, conductor quality (Q) factor, dielectric Q factor, and radiation Q factor. Effective conductivity of the resonator-coated silver is estimated from the experimental unloaded Q factor. The theoretical analysis is validated by the experimental result and the data obtained using the finite-difference time-domain technique. We have designed and fabricated a dual-mode bandpass filter using this resonator. (Author)