An injection-locked frequency divider (ILFD) designed for Ka-band millimeter-wave applications has been implemented in 0.18 µm CMOS process with a wide locking range and a low power consumption. Based on the circuit topology of the differential injection with combining the tailand the direct injectors, the locking range can efficiently be enhanced. Comparing with the conventional ILFD circuits only using the tail-or the direct injection, the proposed ILFD exhibits a flat output power performance with a power consumption of 1.8 mW from a 1.8 V supply at 30 GHz. The measured maximum locking range is about 8.9 GHz ranging from 25.6 GHz to 34 GHz when the injection power level is 4 dBm. The locking range having a 3-dB power rolloff at outputs can also be achieved to 8 GHz ranging from 25.5 GHz to 33.5 GHz.Index Terms -CMOS, injection locking, frequency divider, wide locking range.