Injection-Locked Push-Push Oscillator at 72 GHz Band Using Cross-Coupled HEMTs

An injection-locked push-push oscillator at V-band is developed for high purity millimeter-wave signal source. Cross-coupled HEMTs are applied for the negative resistance generation across wide frequency range and virtually grounded short-ended lines are used for the resonant circuit instead of lumped inductors. Thanks to the differential operation of cross-coupled HEMTs, the push-push oscillator was easily implemented by combing the 2 nd harmonics of oscillation signal at the drain terminals. Injection signal at the fundamental oscillation frequency is applied at the gate of current source FET of cross-coupled FETs for stabilizing the oscillation, which performs the amplification and harmonic generation. The designed oscillator was fabricated using 0.15¿m GaAs pHEMT process. The measurement showed the free-running oscillation around 35.8 GHz and the maximum lock range of 1.48 GHz (2.1%) around 71.6 GHz with the average output power of - 6 dBm.