A 77GHz, +17.5dBm fully-integrated power amplifier (PA) with 50Ω input and output matching is fabricated in a 0.12μm SiGe BiCMOS process. The power amplifier achieves a peak power gain of 17dB and a maximum single-ended output power of +17.5dBm with 12.8% of power-added efficiency (PAE). It has a 3dB bandwidth of 15GHz and draws 165mA from a 1.8V supply. Microstrip tubs are used as the transmission line structure resulting in large isolation between adjacent lines, enabling integration of the PA in a small area of 0.6mm2.