Frequency Stable Microwave Sapphire Oscillators
E.N. Ivanov, Michael E. Tobar
Abstract
We show that state-of-the-art phase noise and high frequency stability could be simultaneously achieved in a microwave oscillator based on the sapphire-loaded cavity resonator. Two 9 GHz sapphire oscillators were constructed with the single-sideband (SSB) phase noise close t −170 dBc/Hz at an offset frequency of 10 kHz and fractional frequency instability less than 2 10−13 for integration times from 5 to 50 s. This work describes the technique for phase-referencing the microwave sapphire oscillator to a stable radio frequency source. We also discuss the suppression of the fast phase fluctuations of the microwave signal due to its transmission through the high- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> resonator.