A SiGe:C BiCMOS 140 GHz wideband frequency multiplier-by-8 with differential output

This paper presents a wideband frequency multiply-by-8 IC for F band FMCW radar application. It combines an active balun, three push-push doubler stages and a buffer stage. The doubler stage uses a transformer for single to differential conversion, with good output balance and compact size. The measured 3 dB output bandwidth of the multiplier is about 30 GHz from 110 GHz to 140 GHz with low harmonics. With 2.5 V power supply, the multiplier can deliver 4.7 dBm output power at 140 GHz and consumes 170 mW.