Design of an 18-50 GHz SiGe HBT Cascode Non-uniform Distributed Power Amplifier

This paper presents the design of an 18-50 GHz SiGe HBT cascode, non-uniform distributed power amplifier (NDPA), which was implemented in 0.13-pm SiGe BiCMOS technology. To expand the NDPA concept into the millimeter-wave (mm-wave) spectrum, a multi-section lumped element artificial transmission line is proposed to synthesize high characteristic impedance of the first and second stage's collector lines, thereby maintaining an optimum load at each active stage over the entire bandwidth. The proposed mm-wave NDPA achieves a peak saturated output power of 19.0 dBm and a peak power-added efficiency (PAE) of 19.1% at 32.0 GHz. The PAE was above 14.2% across the 18-50 GHz bandwidth, which demonstrates the NDPA's optimum power matching capability.