AbstractThis article proposes a CMOS LC‐tank injection locked frequency tripler (ILFT) fabricated in 0.13 μm CMOS process and describes the circuit design, operation principle and measurement results of the ILFT.The differential input/output ILFT circuit is realized with a first‐harmonic injection‐locked oscillator (ILO) stacked in series on two transconductance amplifiers used as a third harmonic generator. The first‐harmonic ILO with a series‐tuned LC resonator amplifies the signal from the third harmonic generated transconductance amplifier. At the supply voltage of 0.75 V, the free‐running frequency of the ILO is from 9.14 GHz to 9.40 GHz. At the incident power of 0 dBm, the total locking range is from the incident frequency 2.95 GHz to 3.43 GHz. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1107–1110, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25101