A wide locking range injection-locked frequency divider with an auto-adjusted injection bias

This paper presents a Ku-band divide-by-2 direct injection-locked frequency divider (ILFD) with a wide locking range (LR) and high input sensitivity. The proposed ILFD incorporates an auto-adjusted injection bias that uses a power detector (PD) to convert the power of the injected signal to a DC voltage. The bias voltage of the injection transistor is then auto-adjusted in response to the output of the PD. The proposed ILFD employs a 2-bit switched capacitor array to further enhance the entire LR. Implemented in a 65-nm CMOS process, the experimental results show that the proposed ILFD achieves an LR of 62.3% (10.5-20 GHz) and 51.2% (11.2-18.9 GHz) at 0 and -10 dBm injection power, respectively. The proposed ILFD consumes 3.6 mW from a 0.6 V supply, and the core area is 0.067 mm2.