Microwave and millimeter wave solid state power amplifiers for future space-based communications and radars

Solid State Power Amplifiers (SSPA) based on Gallium Nitride (GaN) and Gallium Arsenide (GaAs) devices and novel power combining technologies have a very significant potential for use in transmitters in space-based communication equipment and radars replacing expensive, bulky and often unreliable tubes and their associated power supplies. Recent advances in GaN-based Microwave and Millimeter-wave Integrated circuits (MMIC) have clearly demonstrated performance and reliability suitable for their use in high power SSPAs for emerging and existing needs. These include transmitter payloads ranging from commercial broadband communications satellites to earth observation and exploration radars and sensors. Novel power combining techniques offer very compact, highly efficient, robust and reliable implementation of high power amplifiers in frequency range from 17 to 96 GHz, especially in the newly designated frequency bands (Ka, Q, V, E and W) for both space and ground terminals. Since the successful deployment of Ka/Q-band SSPA for Alphasat Aldo Paraboni Propagation/Communication Experiment, the authors have developed and delivered many other SSPAs covering the frequency range of 17-6 GHz for high reliability applications in space payloads, airborne platforms and ground stations using both GaAs and GaN-based devices. Very promising results have been achieved and significant future prospects have been envisaged. Details of these amplifiers and future trends in space-based SSPAs will be presented at the conference.