Phase noise performance of microwave analog frequency dividers application to the characterization of oscillators up to the mm-wave range

The phase noise performance of two different microwave analog frequency dividers is characterized and compared to the values obtained using simple theories of noise in injection locked systems. The direct measurement of the dividers noise with a low phase noise synthesizer being not enough accurate, the residual noise technique is used. The noise levels observed by this technique, between -120 dBc/Hz and -155 dBc/Hz at 10 kHz offset frequency, demonstrate that this dividers noise is much lower than the phase noise of most microwave free running oscillators, even if this noise is still high with respect to the residual noise of amplifiers realized with the same active devices. An application is proposed to the down conversion of microwave sources up to 40 GHz.