Low phase noise X-band push-push oscillator with frequency divider

A MMIC Colpitts oscillator in push-push configuration with integrated frequency divider using InGaP/GaAs HBTs is presented. The output is taken from the second harmonic port while the fundamental signal is fed to a frequency divider by two thus providing a reference signal at one quarter of the output frequency. The MMIC VCO reaches state-of-the-art phase-noise performance in X-band down to -120dBc/Hz at 1MHz offset frequency at high output power and a tuning range of 4%.