A low-power quadrature local oscillator using current-mode-logic ring oscillator and frequency triplers

This letter presents a current-mode-logic (CML) ring oscillator integrated with two frequency triplers for quadrature local-oscillator generation. Quadrature signals and frequency- doubled signals of the CML ring oscillator are propagated to drive two single-balanced mixers for up-converting the frequency by triple and achieving quadrature output and low power consumption. Fabricated by a TSMC 90 nm CMOS technology, the proposed circuit consumed 8.7 mW dc power at a 1.2 V supply voltage and achieved an output frequency of 16.56 to 19.8 GHz (17.8%) at a V_tune of 0 to 1.2 V. The phase noise of -104.6 dBc/Hz was measured from the output signal at a 1 MHz offset frequency. A remarkable figure of merit with a tuning range evaluated at -188.4 was also obtained.