An 80 GHz SiGe Quadrature Receiver Frontend

An in-phase/quadrature (I/Q) receiver frontend for communication and sensing (e.g. radar) applications in the frequency range between 75 and 86 GHz is presented. The frontend includes a low-noise amplifier (LNA), two down-conversion Gilbert mixers, a branchline coupler for the generation of the in-phase and quadrature LO signals, and LO buffers. The circuit was designed and fabricated in a 200 GHz f_T SiGe:C bipolar technology. The chip performance was characterized by on-wafer measurements. From 75 GHz to 86 GHz, the frontend exhibits a single sideband noise figure of 11 dB, and a conversion gain that is higher than 28 dB. The input-referred compression point is -16 dBm. The chip occupies an area of 1000mum times 1100mum. The circuit works from a positive supply voltage of 5.5 V and draws 195 mA