Cryogenic high-Q microwave resonators for stable oscillators

Vitusevich, S.; Winter, M.; Klein, N.

doi:10.1109/77.919563

Journal Article

PreJuSER-40426

Cryogenic high-Q microwave resonators for stable oscillators

Vitusevich, S.FZJ* ; Winter, M.FZJ* ; Klein, N.FZJ*

2001
IEEE New York, NY

IEEE transactions on applied superconductivity 11, 1195 (2001) [10.1109/77.919563]

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Please use a persistent id in citations: http://hdl.handle.net/2128/2103 doi:10.1109/77.919563

Abstract: Cryogenic microwave resonators have a strong potential as frequency stabilising elements for oscillators to be used in advanced radar systems and high-bitrate microwave communication links. Depending on frequency, either 2D planar MTS-resonators, MTS-shielded sapphire TE011 resonators or cryogenic sapphire whispering-gallery mode resonators represent the best compromise between resonator quality factor and size, We have built and tested an all-cryogenic oscillator based on a WG-resonator at f = 23 GHz, Phase noise measurements indicate values superior to quartz stabilized oscillators. A two-step electric frequency tuning consisting of an integrated varactor phase shifter and a dielectric plunger moved by a piezomechanical transducer is introduced to compensate frequency drifting with temperature. For further improvement of long-time frequency stability we have developed rutile-sapphire composite dielectric resonators. Due to the opposite sign of the temperature slope of the dielectric constant of sapphire and rutile a turning point appears in the temperature dependence of the resonance frequency. Employing a moderate temperature stabilization as good as a few millikelvin around the turning point at T = 78 K, we have demonstrated a long time frequency stability at least as good as for oven controlled quartz oscillators.

Keyword(s): J ; low phase noise oscillators (auto) ; dielectric resonators (auto) ; cryocoolers (auto) ; dielectric losses (auto)