A 74-GHz Bandwidth InAlAs/InGaAs-InP HBT Distributed Amplifier with 13-dB Gain

To date, distributed amplifiers based on HBTs have consistently shown lower gain-bandwidth products than their HEMT counterparts. By using improved design techniques, we report in this letter a single-stage distributed amplifier with 13-dB gain and 74 GHz 3-dB bandwidth, based on InAlAs/InGaAs-InP HBTs with 160 GHz f sub T and 140 GHz f sub (max). The high gain and bandwidth results in a gain-bandwidth product of 330 GHz, which is, to our knowledge, the highest reported for HBT-based amplifiers and rivals that of the best InP HEMT distributed amplifiers with e-beam written gate of 0.1-0.15 micron dimension.