A 20.7% locking range W-band fully integrated injection-locked oscillator (ILO) using 90 nm CMOS technology is presented in this paper. The proposed ILO is designed using a ring-based triple-push topology. The free-running oscillation frequency of the ILO is 97.6 GHz. When the input subharmonic number is 3, the ILO demonstrates a locking range from 88.1 to 108.5 GHz without bias tuning, a minimum conversion loss of 14.6 dB, and an output power flatness of within 2 dB. When the input subharmonic number is 6, the locking range is from 96.1 to 98.4 GHz and the minimum conversion loss is 17.2 dB. The dc power consumption is 55.4 mW from L.2-V dc supply voltage. The chip size is 0.733 × 0.492 mm 2. As compared to the previously reported ILOs in the MMW band, our proposed ILO has the widest locking range and good power flatness.