77 GHz SiGe based bipolar transceivers for automotive radar applications — An industrial perspective

Radar sensors operating in the 76-81 GHz range are considered key for Advanced Driver Assistance Systems (ADAS) like adaptive cruise control (ACC), collision mitigation and avoidance systems (CMS) or lane change assist (LCA). These applications are the next wave in automotive safety systems and have thus generated increased interest in lower-cost solutions especially for the mm-wave front-end (FE) section. Today, most of the radar sensors in this frequency range use GaAs based FEs. These multi-chip GaAs FEs are a main cost driver in current radar sensors due to their low integration level. The step towards monolithic microwave integrated circuits (MMIC) based on a 200 GHz ft silicon-germanium (SiGe) technology integrating all needed RF building blocks (mixers, VCOs, dividers, buffers, PAs) on an single die does not only lead to cost reductions but also benefits the testability of these MMICs. This is especially important in the light of upcoming functional safety standards like ASIL-D and ISO26262.