A 38 GHz inverse class-F power amplifier with 38.5% peak PAE, 16.5 dB gain, and 50 mW Psat in 0.13-µm SiGe BiCMOS

This paper presents a 38 GHz 2-stage harmonic-tuned power amplifier consisted of a class-F⁻¹ output power amplifier proceeded by a class-AB driving stage in 0.13 µm SiGe BiCMOS technology. In order to shape highly efficient class-F⁻¹ current and voltage waveforms, the PA adopts multi-resonance series and parallel load networks that modulate load impedance to generate an optimum 50-Ω for signal band, high impedance at the 2^nd harmonic band and low impedance at the 3^rd harmonic band. Inter-stage matching between the driver and output stage is also applied to deliver optimal power to the output stage with a maximum PAE, resulting in 38.5% of peak PAE with 50 mW Psat at 38 GHz, which is one of the highest PAEs in silicon technology at mm-wave. The chip size is 0.9×0.55 µm² including all pads.