A D-Band SiGe Power Amplifier Using a Four-Way Coupled-Line Wilkinson Combiner

This letter presents a four-way power-combinedD-band silicon–germanium (SiGe) power amplifier (PA), which simultaneously achieves high output power and high efficiency. A 4-to-1 planar coupled-line Wilkinson combiner is used, which has low loss and provides broadband impedance transformation. The PA is designed in a 90-nm SiGe BiCMOS technology platform and operates over a bandwidth of 110–145 GHz, with 18.2 dB of gain. The design achieves a peak output power of 21.9 dBm at 130 GHz, with a power-added efficiency (PAE) of 12.5%. The PA maintains greater than 20-dBm output power with greater than 8.7% PAE, from 115 to 140 GHz. This work demonstrates the first silicon-basedD-band PA, which simultaneously achieves greater than 20-dBm output power and 10% PAE.