A low-phase-noise injection-locked oscillator (ILO) based on a cross-coupled oscillator topology is presented. The prototype ILO was designed and fabricated in a 65-nm Partially Depleted SOI (PD-SOI) CMOS technology from STMicroelectronics. The 27.47 GHz free-running oscillator exhibits a phase noise of -119.23 dBc/Hz at 10-MHz offset, and its robustness to process variations is less than 4 dB. Using a common mode injection, the proposed ILO generates an output frequency at 27.5-GHz when the oscillator is injection-locked by the 5th harmonic of a 5.5 GHz reference. In injection-locked mode, the phase noise performance is then -116.75 dBc/Hz and - 135 dBc/Hz at 1-MHz and 10-MHz offsets, respectively, while solely consuming 2.06 mW from a 1 V supply. The total active area is 0.031 mm 2 (excluding I/O pads).