A 29-GHz low phase noise differential voltage controlled oscillator using 2-µm GaAs HBT process

A 29-GHz low phase noise differential voltage controlled oscillator (VCO) using 2-mum AlGaAs/GaAs HBT process is presented in this paper. A common-emitter (CE) topology with a capacitive feedback is utilized to the circuit design. This circuit demonstrates a measured phase noise of -112 dBc/Hz at 1-MHz offset frequency, a tuning range of 0.55 GHz and an output power of higher than 1 dBm.