A highly linear SiGe double-balanced mixer for 77 GHz automotive radar applications

An active double-balanced mixer for automotive applications in the 77 GHz range is presented. The circuit includes on-chip baluns both at the RF and the LO port. The mixer was designed and fabricated in a 200 GHz f/sub T/ SiGe:C bipolar technology. The chip was characterized by on-wafer measurements. At 77 GHz, the conversion gain of the mixer is 11.5 dB. The single sideband noise figure at 77 GHz is 15.8 dB. The input-referred 1 dB compression point at 75 GHz is -0.3 dBm. Measurements across the wafer verified that this mixer circuit is robust against wafer inhomogeneities. The size of the chip is 700/spl mu/m /spl times/ 900/spl mu/m. The circuit was designed for a supply voltage of 5.5 V and draws 75 mA.