Microwave injection-locked oscillator subharmonic locking bandwidth enhancement using multifeedback technique

A novel technique for subharmonic locking bandwidth enhancement in an injection-locked oscillator is demonstrated. The technique introduces an additional feedback path resonating at the desired subharmonic frequency range for the oscillator. A 950 MHz injection-locked oscillator was built and was locked to its 1/3 subharmonic signal. The increase of the subharmonic locking range is significant, up to 8 times depending on the feedback path resistance.