High tuning coefficient whispering gallery modes in a sapphire dielectric resonator transducer

A sapphire dielectric resonator transducer utilizes high tuning coefficient whispering gallery modes in a double disk resonator. The high tuning coefficients and high Q-factors of the whispering gallery modes allow the transducer to achieve very high sensitivity for displacement measurements. In this report, we present an improved mode matching method which can determine the resonant frequencies of the whispering gallery modes in double cylindrical dielectric disk resonators with high accuracy. Two double sapphire disk resonators with different dimensions have been tested to verify the theory. The comparison of the theoretical and experimental results is described. The frequency tuning behaviour of the whispering gallery modes is investigated.<
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