Bias point optimization for low power / low noise applications of advanced SiGe HBT

In this paper, the best trade-off between low power consumption and low noise performance of a commercial bipolar transistor is investigated. In a first step, SiGe HBTs featuring various geometries are benchmarked, focusing on DC characteristics (Gummel plot); this allows the selection of the best device to be measured in microwave range. On this transistor, several figure-of-merits (FoMs) such as cut-off frequencies, minimum noise figure, and available gain, are extracted for the entire DC I(V) characteristic. With the help of iso-curves, our study allows to select optimized biasing range, useful for designers to design Low Noise Amplifiers (LNAs) featuring both low power and low noise performance.