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 tail-and 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.