Comparison between MOS and bipolar mm-wave power amplifiers in advanced SiGe technologies

This article provides a comparison between the performance of MOS and bipolar single stage power amplifiers (PA) in silicon germanium SiGe BiCMOS 55 nm technology from STMicroelectronics. The comparison is made in the same technology node and under similar design conditions (bias current, supply voltage, class of operation and silicon area). Moreover, slow wave coplanar waveguides (S-CPW) were used for matching network in order to reduce the impact of the passive components on the overall performances. Measurement results prove the superiority of bipolar PA in terms of power gain (8.2 dB against 5.5 dB for MOS), and power added efficiency (PAE) (16 % against 12 % for MOS). The output compression point (OCP_1db) and saturation power (P_sat) (7 dBm and 10 dBm respectively) are similar for both amplifiers. These results are clarified through a brief theoretical study. To our best knowledge, the presented bipolar PA has the highest figure of merit (FOM) when compared to the state of art of single stage, common source, class-A, 60 GHz power amplifiers.