A 268 GHz LNA for sub-THz Applications in a 90 nm SiGe:C Technology

This paper presents a fully differential three-stage low noise amplifier (LNA) designed in Infineon's B12HFC technology with an fT/fmax of 300/500GHz. By using cascode stages more gain and a slightly higher noise figure are achieved compared to common-emitter stages. A carefully designed first stage reduces the noise contribution of the subsequent stages and keeps the total noise figure (NF) low. The LNA has a 3 dB-bandwidth of 19GHz (259-278 GHz), a peak gain of 20.5 dB at 268 GHz and a simulated minimum NF of 13.1 dB. The input-referred 1-dB compression point is -16.2 dBm. The chip area, including pads and baluns, is 0.424 mm2 while its core area is only 0.0475 mm2. With its 3.3V supply, the chip draws 56.8mA of current for a total power consumption of 187.4mW.