Design and breakdown behavior of 77GHz variable gain power amplifiers in SiGe-technology

This paper presents two fully integrated differential programmable power amplifiers for automotive radar applications at 77GHz. The power amplifiers were fabricated in a silicon-germanium technology featuring bipolar transistors with an f_t/f_max of 200GHz/250GHz. Measurements have been performed for different temperatures, in particular at -40°, 27° and 125°. A maximum gain of 10 dB is achieved for both amplifiers at room temperature. In addition the breakdown behavior of both amplifiers has been investigated. The building blocks of the amplifiers, which are affected by the breakdown effect had been indentified and design guidelines to avoid breakdown effects in power amplifiers are presented.