31.7 and 36.7 dBm Ka-Band SiGe BiCMOS Power Amplifiers Using Resonated Amplifier Cores and Optimized Power Combining

This paper presents 31.7 dBm and 36.7 dBm (4.7 W) $K_\mathrm{a}$-band power amplifiers (PAs) in a 130 nm silicon germanium (SiGe) BiCMOS technology operating from a 3.5 V supply. High peak power-added efficiency (PAE) of 37 % and 28 % is achieved, respectively. This high output power and efficiency is enabled by refining a PA core design method for large device parallelization and optimized multi stage Wilkinson combiners. The PAs feature a single stage 4-to-1 and two stage 16-way power combiner with a simulated combining loss of only 0.64 and 1.3 dB, respectively. For a 400 MBd 64-QAM signal at an EVM$_\mathrm{RMS}$ of -25 dB, the smaller PA delivers an average output power of 24.7 dBm with an average PAE of 10.6 %, while the larger version achieves 29.2 dBm at 7.1 %.