LC-tank colpitts injection-locked frequency divider with record locking range

A new wide locking range injection-locked frequency divider (ILFD) using a standard 0.18-mu m CMOS process is presented. The ILFD is based on a differential voltage controlled oscillator (VCO) with two embedded injection metal oxide semiconductor field effect transistors (MOSFETs) for coupling external signal to the resonators. The new VCO is composed of two single-ended VCOs coupled with cross-coupled MOSFETs and a transformer. Measurement results show that at the supply voltage of 1.5 V, the divider's free-running frequency is tunable from 5.85 to 6.17 GHz, and at the incident power of 0 dBm the locking range is about 7.1 GHz (65.4%), from the incident frequency 7.3 to 14.4 GHz. The ILFD has a record locking range percentage among published divide-by-2 LC-tank ILFDs.