A 10-w, 6-GHz, gaas impatt amplifier for microwave Radio systems

An experimental 10-W, three-stage, GaAs IMPATT amplifier has been developed with transmission characteristics suitable for use in 6-GHz long-haul radio-relay systems. The amplifier uses five flat-doping-profile GaAs IMPATT diodes in three cascaded, circulator-coupled stages. The dc input power is 153 W with a nominal 10 W of output power and an overall noise figure of less than 35 dB. The overall amplifier efficiency is 6.5 percent. The major portion of the amplifier is constructed in strip transmission line using suspended alumina substrate in an aluminum housing. Small, integrated, coaxial sections with coaxial transformers connect the diodes to the strip transmission line circuits. The amplifier is cooled by free convection.