A 240GHz Synthesizer in 55nm SiGe BiCMOS

A 234-261GHz synthesizer with 2-4.9dBm output power and -105 dBc/Hz phase noise at 10MHz offset is fabricated in a production 55nm SiGe BiCMOS process with 330/350GHz HBT f
_T
/f
_MAX
. The circuit includes a 120GHz fundamental frequency VCO with 1.2V AMOS varactors, a broadband LO tree driving a divide-by- 128 chain and a doubler. The doubler has a maximum output power of 5.5 dBm at 240 GHz and 11.9% efficiency. The total power consumption of the synthesizer is 467 mW from 2.5V, 1.8V and 1.2V supplies.