A 60-GHz 20.6-dBm symmetric radial-combining wideband power amplifier with 20.3% peak PAE and 20-dB gain in 90-nm CMOS

A 60-GHz 1.2-V wideband power amplifier (PA) with a compact 4-way radial power combiner implemented in 90-nm CMOS process is presented in this paper. The transformer-based radial power combiner with 1-dB insertion loss at 60 GHz and 0.043-mm
²
compact size is designed for high output power combining and wideband load-pull matching. This PA achieves saturated output power (P
_SAT
) of 20.6 dBm, maximum power added efficiency (PAE
_max
) of 20.3%, and 20.1-dB small-signal gain (S
₂₁
) at 60 GHz. The PA maintains flat 20-dBm PSAT with PAE
_max
better than 17.3% within 50-64 GHz, and it has a 3-dB bandwidth (3-dB BW) of 24.5 GHz (41.8-66.3 GHz). The chip area without pads is 0.432 mm
₂
. To the author's best knowledge, this PA with flat 20-dBm P
_SAT
presents the widest large-signal bandwidth (50-64 GHz) compared to other 60-GHz CMOS PA.