A 60-68GHz Three-coil-Coupling VCO Achieving 186dBc/Hz FoM in 28nm CMOS

In this paper, a quad-core LC VCO design was implemented using 28nm CMOS technology. The tuning range achieved was 60 GHz to 68 GHz (12.5%). In this design, the four identical VCO cores were synchronized using mode suppression, and the use of slab inductor allowed for breaking the frequency limitations. Each VCO core employed three coupling coils to increase V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS</inf> . At 60 GHz, a phase noise performance of -104.8 dBc/Hz was achieved at 1 MHz frequency offset. The VCO consumed 24 mW power, and the figure of merit (FoM) at 1 MHz offset was 186 dBc/Hz.