A 52-to-61 GHz Push-Push VCO in 28 nm CMOS

We present a continuously tunable 52-to-61 GHz push-push cross-coupled voltage-controlled oscillator (VCO) in a 28 nm bulk CMOS technology. The second harmonic is extracted in a non-invasive way using a transformer. The primary side acts simultaneously as a second harmonic filter and a balun. The VCO achieves in measurement a low phase noise of -87 dBc/Hz at 1 MHz offset at 60 GHz and an output power of -23 dB,. The VCO including buffers dissipates 49 mA from a single 0.9 V supply, while the VCO core consumes only 12 mA. It occupies a chip area of only 0.28 mm
²
including pads. The VCO achieves a continuously tunable frequency tuning range (FTR) of 16%. The circuit is suitable for 60 GHz FMCW radar applications.