A Transformer-based Injection-Locked Frequency Divider in 65-nm CMOS Technology

A divide-by-four injection-locked frequency divider (ILFD) for 5G millimeter-wave communication system is presented in this paper. In this frequency divider, A transformer-based fourth-order resonator is proposed to boost the third-order harmonic in the oscillator to increase the injection efficiency and thus the locking range. Besides, a buffer with harmonic rejection is adopted for the ILFD output harmonic suppression, resulting in a third-harmonic rejection ratio (HRR3) over 14.8dB. At 0 dBm power injection, a locking range of 30.16% from 24.5 GHz to 33.2 GHz is achieved for the proposed ILFD, with 9.7 mW power consumption under 0.6 V supply. The chip is implemented in 65nm CMOS process with die area of 0.448 mm
²
.