LAUSR

The performance of the power amplifier determines the detection capability of 77 GHz automotive radar, and the bias circuit is one of the most important parts of a silicon-germanium power amplifier. In this paper, we discussed and designed an on-chip bias circuit based on a silicon-germanium heterojunction bipolar transistor, which is used for the W-band silicon–germanium power amplifier. Considering the low breakdown voltage and the correlation between characteristic frequency and bias current density of the silicon-germanium heterojunction bipolar transistor, the bias circuit is designed to improve the breakdown voltage of the power amplifier and meet the W band characteristic frequency at the same time. The simulation results show that the designed bias circuit can make the amplifier operate normally from −40 to 125 °C. In addition, the output power and smooth controllability of the power amplifier can be adjusted by controlling the bias circuit.