Investigation of differential broadband amplifiers in normally-on mHEMT technology

This paper presents differential DC-28 GHz two stage baseband amplifier topologies realized in a 35 nm gate length InAlAs/InGaAs mHEMT technology. They are intended as buffer amplifiers of future single-chip receiver MMICs for point to-point communication systems. Implementation possibilities of DC-offset cancellation and gain control without affecting the bandwidth are shown for the normally-on mHEMT technology. DC-offset levels up to ±0.2V can be compensated. The required chip area is 0.1mm2 and the presented circuits are therefore suitable for integration in single-chip sub mm-wave receiver MMICs.