A 31.5-to-40.5 GHz injection-locked CMOS frequency tripler with injection-current enhancement technique

This letter presents an injection-locked 36 GHz frequency tripler (ILFT) for 5G applications. With the high order transformer based LC tank, over the target operating frequency range its phase response is flat at around 0 degree, and the injection-current is enhanced with a 3rd harmonic LC tail filter, thereby achieving a wide locking range. Fabricated in a 65 nm CMOS process, the ILFT consumes about 7.2 mW from a 0.6 V supply, and its core area without the output buffer and input matching network is only 0.25 x 0.4 mm(2). With 0 dBm input injection power, the proposed ILFT achieves a locking range from 31.5 to 40.5 GHz (25%).