Design and Performance of a 600-W $C$ -Band Amplifier Using Spatially Combined GaAs FETs for Satellite Communications

This paper describes the design and performance of a C -band amplifier with over 600 W of saturated output power. This amplifier is intended for use in commercial broadcast satellite uplink base stations. The amplifier uses spatial power combining to combine the output powers of sixteen internally matched 45-W GaAs FETs. The amplifier also comprises pre-amplification and driver amplification stages, a level control variable attenuator, and a predistortion linearizer. The unit also includes a power supply as well as a user monitor and control interface. We will present various measures of this amplifier's linearity performance, demonstrating its suitability for use in broadcast applications. Finally, we will present results from power combining two of these amplifiers, resulting in a solid-state amplifier with 1.4 kW of saturated C -band output power.