An enhanced locking range technique for a CMOS injection-locked frequency divider (ILFD) is presented, which uses a cross-coupled oscillator with a dual-resonance RLC resonator. This ILFD has dual locking ranges at a fixed bias, and the resistor in the resonator is used to have overlapping dual locking ranges so that a single-band wide-locking range is obtained. At the incident power of 0 dBm, the locking range of the divide-by-2 ILFD is 6.7 GHz, from 3 to 9.7 GHz, and the locking range percentage is 105.51%.