Watt-Level Ka-Band Power Amplifiers in 130-nm SiGe BiCMOS

This article presents two Ka-band power amplifiers (PAs) in a 130-nm silicon germanium (SiGe) BiCMOS technology achieving 31.7- (1.5 W) and 36.7-dBm (4.7 W) saturated output power while maintaining a peak power-added efficiency (PAE) of 36.7 and 28%, respectively. The PAs use a 3.5-V supply. The designs pair a refined core design method, which enables efficient device parallelization and optimized transmission line (TL) combiners. The smaller PA utilizes a single-stage 4-to-1 combiner with an expected insertion loss of 0.64 dB from electromagnetic (EM) simulation. For the larger PA, a two-stage 16-way power combiner with an insertion loss of 1.3 dB is used. Under modulated excitation with a 400-MBd 64-QAM signal, both PAs demonstrate high average output power beyond 24 and 29 dBm.