Skip to Main Content
Nonlinear properties of high-temperature superconducting (HTS) strongly coupled resonators at different input power have been investigated by measurements of the quality factor as a function of input power as well as by generation of the intermodulation distortion (IMD). The double-sided YBCO films on CeO2 buffered sapphire demonstrate advanced performance with the microwave surface resistance of ∼0.3 mΩ at 8.5 GHz at 77 K and an IMD third-order interception point estimated at Pcirc≈70 W. A parallel feedback oscillator was assembled using a transmission type HTS resonator cooled with liquid nitrogen and a room temperature low noise amplifier. Results on the phase noise investigation of the 2.3 GHz oscillator based on HTS resonator operated in the nonlinear regime demonstrated a deviation from the simple model of the phase noise, which predicts an up-conversion of 1/f noise of the amplifier to oscillator phase noise. The latter can be explained by the phase noise introduced additionally due to the nonlinear response of the HTS resonator.
Date of Publication: June 2003