Fully Qualified Gallium Nitride Power Amplifier for Use in Ka-Band Commercial Space Applications

There is a need for Solid State Power Amplifiers (SSPA's) to be used in High Throughput Satellites (HTS) for commercial applications. Specifically when the amount of information passed through the transponders, i.e. capacity, is determined mainly by the quantity of beams the satellite can generate. This application is well suited for SSPA's over the conventional TWTA solution as they are smaller and lighter weight enabling a simplification of HTS payload architectures, higher density physical integration, and the ability to support active array transmit solutions all of which increases the quantity of beams and thus capacity. More specifically, Gallium Nitride (GaN) Power Amplifiers (PA's) have shown the ability to generate high RF output power levels with small size and high efficiency thereby enabling step function improvement in capacity [1], [2]. This paper will describe a 20GHz fully space qualified GaN PA module developed for KaBand commercial satellite downlinks. The design techniques, test results, and screening regimen required to meet the demanding performance and reliability requirements will be given. The result is a 20GHz module with >55dB of gain, >10W of Pout, >30% peak PAE, and NPR >15dB. To the authors knowledge this is the best fully space-qualified module performance at this frequency published to date.