Recent developments in solid state power amplifier technology and their applicability to third generation mobile space segment systems

It is anticipated that INMARSAT´s third generation mobile satellite system will be typified by the necessity to provide for a continuation of global communications whilst simultaneously meeting the requirements for communications to a large number of smaller mobile Earth stations on a regional basis. ESA´s ARAMIS project has covered considerable ground in assessing payload configurations to provide at least one example of such a multimission mobile satellite service. Emerging from that study was the criticability of a number of functional areas but in particular the L-band power amplifier. A number of active multiple-beam phased array systems are examined and each assessed in terms of the requirements of the distributed high power L-band power amplifier subsystem. Various classes of power amplifier design are discussed and a novel quasilinear design described which has very specific applications in phased array systems up to S-band