Adaptive techniques to improve the efficiency of GaN based SSPAs up to C Band for geo synchronous satellites

Abstract

quotIn this thesis, various adaptive techniques to improve the efficiency of Solid State Power Amplifier (SSPA) for Geo Synchronous Satellite are presented. The Microwave Power Amplifiers (MPAs) being the most important sub-system determining payload weight, volume, cost and many important link parameters, their performance is improved by novel techniques. Out of various techniques available, the important techniques like flexible (adaptive) output power, flexible frequency and bandwidth, flexible thermal management, adaptive temperature compensation, replacement of Travelling Wave Tube Amplifiers (TWTAs) by Solid State Power Amplifiers (SSPAs) and improvement of reliability of SSPAs are presented in detail. newline newlineLiterature survey on reported techniques to reduce the cost of the satellite services, making the satellite payload flexible and development of newly emerging technology, Gallium Nitride (GaN) based SSPAs to replace the TWTAs are included. The recent development on a new technique so called flexible payload or adaptive payload is described. This new architecture known as of Generic Flexible Payload (GFP) has been proposed by European Space Agency and Astrium, which allows to meet various requirements like evolving business and political landscapes, the emergence of new technologies and applications, or even a change of orbital location or owner. The adaptive or flexible payload allows the user to redefine the frequency plan, redistribute the transmit power between service regions and change the EIRP according to the specific need without scarifying the satellite performance. newline newlineRecent development on GaN based SSPAs by various authors are also included. SSPA being the complex sub-system, especially for Geo-Synchronous Satellite, major specifications including Reliability and Quality Assurance criteria are described in detail. The nominal value of each parameter for 200 watt GaN based SSPA is also given. newline