W-Band HEMT-oscillator with stabilization by phase controlled subharmonic injection locking

A coplanar subbarmonic injection locked W-band HEMT VCO with an integrated varactor diode and buffer amplifier was developed, achieving a tuning range of 10 GHz and an output power of 8 dBm at 94 GHz. The oscillator was stabilized by subbarmonic injection locking to reducephase noise and simultaneously by an external phase-locked-loop (PLL) circuit to compensate for temperature drift. The locking range of the system was extended to 1 GHz by the use of the PLL circuit.