F Band Distributed Active Transformer Power Amplifier Achieving 12 Gb/s in InP 130-nm HBT

This work demonstrates a compact, low-loss distributed active transformer (DAT) for 8-to-1 power combining at 120 GHz. Using the DAT as an output matching network, the proposed power amplifier (PA) in 130-nm InP heterojunction bipolar transistor (HBT) presents 11.5% power-added efficiency (PAE) and 8.6-dB gain at 22.1-dBm peak output power. It also shows a 3-dB small-signal bandwidth from 100 to 140 GHz. To the author’s best knowledge, this is the first demonstration of a DAT PA at frequencies exceeding 100 GHz. QPSK, 16 QAM, and 64 QAM modulation measurements were performed at 121 GHz. A data rate of 12 Gb/s is achieved with 14.5-dBm output power and 3.3% PAE using 16 QAM modulation at 8.0% root-mean-square (rms) error vector magnitude (EVM).