Lumped DC-50 GHz amplifier using InP/InGaAs HBTs

A direct-coupled, lumped broadband amplifier utilising InP/InGaAs single heterojunction bipolar transistors (SHBTs) is presented. The achieved –3 dB bandwidth is 50 GHz with a DC gain of 9.8 dB and a gain peak of only 1.2 dB. This is the largest bandwidth reported for InP/InGaAs HBT amplifiers with such a flat gain curve.