A 7–115-GHz Distributed Amplifier With 24-dBm Output Power Using Quadruple-Stacked HBT in InP

In this letter, we present the designs and development of a wideband, high output power quadruple-stacked heterojunction bipolar transistor (HBT) distributed amplifier (DA). In particular, the stacked HBT configuration can improve gain and output power while achieving a very wide bandwidth. To validate the proposed design concept, a quadruple-stacked HBT DA is designed in an indium phosphide (InP) process. The measurement results show an average gain of 16 dB from 7–115-GHz bandwidth with a maximum of 24-dBm saturated output power (
$P_{\mathrm {sat}}$
). To the best of the authors’ knowledge, this is the first time quadruple-stacked HBT is used in a DA to achieve the highest output power compared with other published work in the same frequency range.