This letter presents a wide frequency tuning range (FTR), fault‐tolerant, and common‐mode‐noise (CMN)‐suppressed LC‐VCO using the Reversed‐varactor (RV) technique. The RV technique maintains a wide frequency tuning range, ensures that the CMN emitted from the internal devices and external working environment is not multiplied by KVCO2, and improves the fault‐tolerant property of the LC‐VCO. The simulation results show that this technique reduces the phase noise (PN) by 6d Bc/Hz to 6.8 dBc/Hz, while the frequency fluctuation due to the single‐event‐transient (SET) effect decreases by about 90.2%. The proposed LC‐VCO works from 14.6 GHz to 21.3 GHz, has ‐100.3 dBc/Hz@1 MHz at 18.2 GHz working frequency and 5.7 mW power consumption. [ABSTRACT FROM AUTHOR]