Extended-resonant output matching design for 24GHz transformer-coupled CMOS VCO

An extended-resonant output matching circuit was proposed to enhance the negative conductance, output power and phase noise of a 24 GHz transformer coupled voltage controlled oscillator (VCO). The circuit was realized by a capacitive stub-loaded resonator in a voltage boosted scheme to steepen the phase slope of the oscillator. The designed VCO achieved a peak output power of +1.5dBm at 23.82 GHz and a phase noise of -117 dBc/Hz at 1MHz offset frequency. Meanwhile, the VCO exhibits the excellent monotonic and constant frequency tuning characteristics with nearly flat output power.