Integrated Doherty power amplifiers for satellite systems: challenges and solutions

This paper discusses the possible exploitation of the Doherty technique, very popular in mobile communication applications, in the design of integrated power amplifiers for satellite systems. The work focusses on the advantages and disadvantages of Doherty power amplifiers compared to other solutions, by presenting the specific features of the Doherty design in the framework of the very demanding requirements of space applications. In particular, satellite applications in the millimetre-wave spectrum are strong candidates for utilising integrated Doherty power amplifiers. In that context, the intrinsic limitation of the Doherty technique at millimetre-wave frequencies will be discussed, presenting solutions in terms of technology and design to improve gain, bandwidth, efficiency, and linearity. Some state-of-the-art examples are shown and analyzed, emphasizing the most relevant results achieved so far.