A 19.1–25.5-GHz Compact Dual-Mode Rotary Traveling-Wave Oscillator With 195.4-dBc/Hz FoM

In this letter, a dual-mode rotary traveling-wave oscillator (RTWO) is proposed to achieve wide operation bandwidth and multiple phases. Two twisted differential transmission lines are coupled together to form the dual-mode traveling-wave resonator. Sixteen pairs of back-to-back inverters and capacitors are connected to the resonators to introduce the multicore multi-phase operation. The mode switches are used to control the coupling direction and select the desired mode without degrading the quality factor. Verified in a 40-nm CMOS process, the proposed dual-mode RTWO exhibits a dual-mode frequency range from 19.1 to 25.5 GHz with the core size of 0.08 mm
$^{\textbf {2}}$
. The measured 10-MHz phase noise at 25.30 and 22.12 GHz is −129.6 and −131.5 dBc/Hz, respectively. The best FoM and FoMT are 186.2 and 195.4 dBc/Hz, respectively.