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 30GHz and 50GHz sub-harmonic injection-locked VCOs is realized in a 90nm digital CMOS process and able to lock from 2
^nd
to 8
^th
harmonic of the reference frequency with locking range reaching 5.6GHz. Simultaneous locking to the 3
^rd
and 5
^th
harmonics of a 10GHz reference signal is also demonstrated.