A 230–310 GHz down converter with integrated local oscillator in 65 nm CMOS technology

In this work, we present an integrated 230-310 GHz heterodyne down converter in 65 nm CMOS technology. The circuit includes a mixer and a local oscillator based on a Colpitts topology VCO. The on-chip oscillator generates a 88-95 GHz fundamental tone but drives the mixer with the 3^rd harmonic around 270 GHz. The down converter measured conversion loss is about +25.5 dB around 280 GHz. The measured noise figure is 25.5 dB which is the lowest reported above 220 GHz in CMOS technology, moreover the down converter has an IF 3-dB bandwidth of more than 20 GHz. The chip size is 0.226 mm² including pads and consumes 76 mW of DC power from a 1.8 V supply. An additional version of the down converter is fabricated without integrated VCO to investigate the mixer performance in the same frequency range.