This work presented a fundamental injection-locked oscillator (ILO), based on a modified common collector Colpitts topology. An injection buffer improves the sensitivity and reverse isolation and a common base output buffer reduces loading effects. The circuit achieves a wide tuning range of 50 GHz, with a high output power of 2.5 dBm and has a free-running oscillation frequency of 185.8 GHz. The total dc power consumption is 30 mW from a single 2.5 V supply, resulting in a dc-to-RF efficiency of 5.9 %. The circuit is intended for mm-wave communication systems operating around 180 GHz and can be combined with a frequency multiplier to achieve a spectral-clean reference signal, with excellent noise performance. The final chip occupies an area of 0.32 mm2 and is implemented in a 130 nm SiGe BiCMOS process, which offers a maximum oscillation frequency f max of 450 GHz. This circuit demonstrates one of the highest efficiencies and locking ranges for an ILO, compared to the state-of-the-art.
