LINC transmitter architecture for nano-satellite applications

The growing interest in the area of nano-satellite development has escalated in the recent years. Space agencies and private industries have started developing nano-satellites for more serious missions in the areas of Space Operations, remote sensing and Space Research. The sudden increase in the number of nano-satellite missions has led to a challenge in frequency coordination, this has led to investigating spectrally efficient modulation schemes. This paper deals with the challenges in incorporating spectrally efficient modulation schemes such as 16-APSK, 32-APSK and QAM modulations. The major challenges is to design a transmitter/PA that can both efficiently and linearly amplify such signals, this paper describes a trade-off performed on various efficiency and linearity enhancement techniques to choose the most appropriate transmitter/PA architecture for nano-satellites and discusses the measurement results performed on a LINC PA that was designed for 900MHz.