High Q-Factor Graphene-Based Inductor CMOS LC Voltage Controlled Oscillator for PLL Applications

This work examines the design of high Q-factor inductor for LC voltage-controlled oscillator (VCO) in TSMC 0.18μm n-well CMOS process technology and 1.5 V supply voltage. The planar structure of graphene and its sufficient relation time make it easier to pattern graphene into helical structures without additional contacts at each corner. The inductor is modelled with the widely accepted π-mudel and the results show that graphene inductor achieves a high Q-factor with reduced parasitics and losses when compared with Cu wire inductor. Following this, we employed the inductor in the design of 2 GHz LC VCO. From the Cadence/Spectre simulations, we obtained that the tuning range of voltage-controlled oscillator is 1.62 GHz to 3.93 GHz and the phase noise measured is -124.8 dBc/Hz at 1 MHz offset frequency. In addition, the VCO has a figure of merit (FoM) of206.4 dBc/Hz and consumes 3.66 mW power.