Simultaneous sub-harmonic injection-locked mm-wave frequency generators for multi-band communications in CMOS

A technique for generating multiple mm-wave carrier frequencies is introduced, using simultaneous sub-harmonic injection locking of multiple VCOs to a single reference frequency. A prototype of 30 GHz and 50 GHz sub-harmonic injection-locked VCOs is realized in a 90 nm digital CMOS process and able to lock from 2^nd to 8^th harmonic of the reference frequency with locking range reaching 5.6 GHz. Simultaneous locking to the 3^rd and 5^th harmonics of a 10 GHz reference signal is also demonstrated.