This talk describes a dual
path synchronized quad core oscillator with a circular transformer
directly synchronizes both adjacent and non adjacent cores, breaking the trade off between the
frequency mismatch induced PN penalty and Q of the inductor in the coupled oscillator. Thus,
low PN and high FoM are achieved simultaneously. The 22.36 to 26.84GHz oscillator prototyped
in 65nm CMOS exhibits best in class PN@10MHz (−138dBc/Hz) and FoM@10MHz
(193.3dBc/Hz) at 25.78GHz, and a low frequency pushing of 17 to 4 4MHz/V.