A 208 GHz InP Distributed Amplifier with Combining Loss Reduction Techniques

This paper introduces a wideband distributed amplifier (DA) using Indium Phosphide (InP) heterojunction bipolar transistor (HBT) technology that achieves a 208 GHz bandwidth. The DA comprises eight uniform gain cells, each employing a triple-stacked topology with capacitive coupling and resistive/capacitive degeneration techniques to reduce input capacitance and minimize input transmission line loss at high frequencies. The DA delivers an average gain of 11 dB and a maximum saturated output power (Psat) of 14.6 dBm, while maintaining an average Psat of 13.6 dBm up to 175 GHz. It also achieves a maximum 1 dB gain compression power (P1dB) of 10.7 dBm, with an average P1dB of 9.3 dBm.