A 234–261-GHz 55-nm SiGe BiCMOS Signal Source with 5.4–7.2 dBm Output Power, 1.3% DC-to-RF Efficiency, and 1-GHz Divided-Down Output

Abstract

A 234-261-GHz signal source with record 7.2-dBm output power at 240 GHz and -105 dBc/Hz phase noise at 10-MHz offset is reported. Fabricated in a production 55-nm SiGe BiCMOS process with HBT f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> /f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MAX</sub> of 330/350 GHz, the circuit includes a 120-GHz fundamental frequency VCO with 1.2-V AMOS varactors, a broadband MOS-HBT cascode LO tree driving a divide-by-128 chain, and a doubler with a record drain efficiency of 11.9%. The total power consumption of the signal source is 386 mW resulting in a DC-to-RF efficiency of 1.3%. A detailed discussion of the candidate LO-tree and doubler topologies and of the design methodology, which capitalizes on the MOS-HBT cascode and unique features of the 55-nm SiGe BiCMOS process, is provided.