A K-Band CMOS Low-Phase-Noise Sub-Harmonically Injection-Locked QVCO with Divider-Less Frequency-Tracking Loop
A K-band CMOS low-phase-noise low-jitter sub-harmonically injection-locked quadrature voltage-controlled oscillator (QVCO) with divider-less frequency-tracking loop is proposed using 90-nm CMOS in this paper. The sub-harmonically injection-locked QVCO is designed using current-reused topology with enhanced self-injection coupling to achieve low dc power. To widen the locking range for the sub-harmonically injection-locked operation, a transformer coupling is adopted in the QVCO. Furthermore, a divider-less frequency-tracking loop is employed in the sub-harmonically injection-locked QVCO to adaptively align the control voltage of the QVCO. With a sub-harmonic number of 8 and a dc power consumption of 24.4 mW, the measured locking frequency range is from 21.7 to 23.2 GHz with an output power of higher than -3 dBm. The measured minimum phase noise at 1-MHz offset and jitter integrated from 1 kHz to 40 MHz are -125.2 dBc/Hz and 32.4 fs, respectively.