DC-38GHz Nonuniform Distributed Amplifier Design with Gate and Drain Line Optimization Using 0.1µm GaAs pHEMT Technology

Abstract

This paper presents an optimized three-cell Nonuniform Distributed Amplifier (NUDA) suitable for optoelectronic drivers in the Q band. This is the first NUDA of Darlington topology designed with the 0.1µm GaAs pHEMT process with a transition frequency fT of 130GHz. Gate microstrip line sections, drain microstrip line sections, and active device sizes were optimized to obtain high gain and large bandwidth from a Monolithic Microwave Integrated Circuit (MMIC) Distributed Amplifier (DA). This paper presents two NUDA designs with different topologies. The first was designed with a three-stage Common Source (CS) topology that enhanced the bandwidth up to 34GHz with a gain greater than 8dB, and the second was designed with two Darlington stages and one CS stage that enhanced the bandwidth up to 38GHz with a gain greater than 8dB. The bandwidth enhancement of NUDA with the Darlington topology was compared and verified with the NUDA of common source topologies.