K-Band 8-Watt Power Amplifier MMICs using 150nm GaN process for Satellite Transponder

Abstract

This paper presents the design and measured performance of a novel 20.5-25.5GHz 8-Watt Power Amplifier (PA) Monolithic Microwave Integrated Circuit (MMIC). The circuit provides linear gain higher than 20dB, output power of 8-Watt and Power Added Efficiency (PAE) better than 30% over the band. The MMIC is designed using $0.15\mu m$ GaN highelectron mobility transistor (HEMT) based GH15 process from UMS foundry. Two identical amplifiers are designed except different output power matching networks (OMN) to better understand effectiveness of novel OMN presented in the paper. Novel output power matching circuit used in the power amplifier adds minimum loss and reduces the spread of output impedance over the frequency to obtain output power, PAE and output matching over wider band. Total four HEMTs of size $75 \mu m x 8$ are combined at final output stage to obtain desired output power. Transformation of output impedance from single point 50Ohm to required impedance for optimum PAE for HEMT is discussed in detail using smith chart showing contribution of each matching element.