A 119 GHz Bandwidth Distributed Amplifier with a ±2 ps Group Delay Variation

This paper presents an analysis on the bandwidth and group delay variation of the artificial transmission line structures that are inherent to distributed amplifiers. An Indium-Phosphide (InP) distributed amplifier consisting of four buffered cascode cells is presented, which reaches a bandwidth of 119 GHz. The gain is 18.2 dB and the average in-band output 1 dB compression point is 10.9 dBm. The group delay has a variation of ±2 ps between 14 GHz and 119 GHz. To the authors knowledge this is the smallest reported group delay variation for amplifiers with a bandwidth beyond 50 GHz.