A differential 77-GHz receiver with current re-use low-noise amplifier in SiGe technology

This paper presents a differential current re-use stacked double common-emitter stage low-noise amplifier and corresponding receiver frontend for 77 GHz automotive radar systems. Both circuits have been manufactured in an improved SiGe:C HBT technology with f
_t
/f
_max
= 200/250 GHz and can operate in differential or single-ended mode. The receiver shows a gain of 24.5 dB and single sideband noise figure of 15.8 dB. The gain and noise figure of the LNA in single-ended mode are 12 dB and 9.5 dB respectively, suggesting a differential noise figure of approximately 6.5 dB.