A single-ended 77/79 GHz monolithic microwave integrated circuit (MMIC) receiver has been developed in SiGe HBT technology for frequency-modulated continuous-wave (FMCW) automotive radars. The single-ended receiver chip consists of the first reported SiGe 77/79 GHz single-ended cascode low noise amplifier (LNA), the improved single-ended RF double-balanced down-conversion 77/79 GHz micromixer, and the modified differential Colpitts 77/79 GHz voltage controlled oscillator (VCO). The LNA presents 20/21.7 dB gain and mixer has 13.4/7 dB gain at 77/79 GHz, and the VCO oscillates from 79 to 82 GHz before it is tuned by cutting the transmission line ladder, and it centres around 77 GHz with a tuning range of 3.8 GHz for the whole ambient temperature variation range from -40degC to +125degC after we cut the lines by tungsten-carbide needles. Phase noise is -90 dBc/Hz@l MHz offset. Differential output power delivered by the VCO is 5 dBm, which is an optimum level to drive the mixer. The receiver occupies 0.5 mm2 without pads and 1.26 mm2 with pads, and consumes 595 mW. The measurement of the whole receiver at 79 GHz shows 20-26 dB gain in the linear region with stable IF output signal. The input P1dB of the receiver is -35 dBm.