A 1-V, 19.2-mW, 308-GHz Push–Push Balanced Colpitts Oscillator in 70-nm GaAs pHEMT Technology

This paper presents a submillimeter-wave (submm-wave) push–push Colpitts oscillator that supports very low supply voltage operation using 70-nm GaAs pHEMT technology. The oscillator core employs a common-drain (CD) balanced Colpitts topology with loaded shunt LC resonators at the drain, thereby constructively enhancing the second-harmonic (2f 0) signal while suppressing unwanted harmonics. At an oscillation frequency (f osc) of 312 GHz, the VCO delivers an output power (Pout) of -16.9 dBm and a phase noise of -85.3 dBc/Hz (at 10-MHz offset), while consuming 41 mW from a 1.6-V supply. With the supply scaled down to 1 V, the VCO achieves an f osc of 309 GHz and consumes only 25.6 mW. The VCO occupies a compact chip area of 370 μm × 445 μm (0.17 mm2). To the best of the authors’ knowledge, this is the first GaAs oscillator operating above 300 GHz with such low supply voltage.