This work demonstrates that ultra-low phase-noiseoscillators with a single-sideband phase-noise spectral densityapproaching –160 dBc/Hz at Fourier frequency of 1 kHz canbe constructed at microwave frequencies (8 to 10 GHz). Suchnoise performance has been achieved by frequency locking aconventional loop oscillator to a temperature-stabilized sapphiredielectric resonator operating at a relatively high levelof dissipated microwave power (~0.5 W). Principles of microwavecircuit interferometry have been employed to generatethe error signal for the oscillator frequency control system. Nocryogens were used.Two almost identical oscillators were built to perform theclassical 2-oscillator phase noise measurements. The phase referencingof one oscillator to another was achieved by varyingmicrowave power dissipated in the sapphire resonator.
|Journal||IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control|
|Publication status||Published - 2009|