V-band varactor-less interpolative-phase-tuning oscillators with multiphase outputs

An interpolative-phase-tuning technique is presented to tune the frequency of millimeter-wave LC-based ring oscillators without using varactors. Two oscillator prototypes are designed and implemented in a 0.13-μm CMOS process. The first oscillator operates at 50GHz with 8 output phases and measures phase noise of -127.8dBc/Hz at 10MHz offset, tuning range of 6.8%, and figure of merit (FOM) of 186.4dB while occupying chip area of 0.36mm². The second prototype oscillates at 60GHz with 4 output phases and measures phase noise of -120.6dBc/Hz at 10MHz offset, tuning range of 9%, and FOM of 180.6dB with chip area of 0.2mm².