IS-Ⅲ系统是一个距中继站有36,000公里的定向发射系统,它以5,925～6,425千兆赫的频率范围工作在定向无线电地面站上。日益增长的通讯密度和通过电视进行的世界范围的通讯联络需要经济地复盖波段。于是,大地面站将把很多通话线束(每个由120个话路组成)和一个或多个电视波段送上卫星。这种多载波工作可以通过聚集在发射天棱上的数个窄频带功率末级来实现,或者由一个具有相应功率的宽频带末级来承担多载波工作。为这种末级放大器研制了三种功率行波 The IS-III system is a directional transmission system 36,000 kilometers from the repeater station and operates on a directional radio ground station in the frequency range 5,925-6,425 GHz. Growing density of communications and world-wide communications via television require coverage of the band economically. As a result, the large earth station will send many of the call bundles (each consisting of 120 channels) and one or more television bands to the satellite. This multi-carrier operation can be achieved by gathering several narrowband power end stages on the transmit edge or by a wideband end stage with corresponding power. Three kinds of power traveling waves have been developed for this final stage amplifier