Low phase noise injection-locked doubler-based quadrature CMOS VCO

This paper presents a low phase noise injection-locked doubler-based quadrature voltage controlled oscillator (ILD-QVCO). Instead of using conventional coupling scheme, an injection-locked doubler is introduced in the proposed ILD-QVCO to generate quadarature signals. In this architecture, phase noise is determined by the coupled VCOs, and the phase accuracy is determined by VCO oscillating at twice of the desired frequency. Thus, the trade-off between the two parameters in traditional QVCO does not exist in the ILD-QVCO. Besides, the novel QVCO proves to have a better phase noise than conventional QVCO. The proposed ILD-QVCO is designed and simulated in TSMC 130nm CMOS 1P8M process. Simulation results show that the ILD-QVCO has a phase noise of -120.4 dBc/Hz at an offset frequency of 1MHz from a 6.1GHz carrier, and draws a 7.15-mA current from a 1.2-V supply voltage. A 186.7-dB figure of merit (FOM) is achieved.