50 % High Efficiency X-Band GaN MMIC Amplifier for Space Applications

This paper describes the design methodology and the measured results of a X-band 2 stage MMIC HPA developed for space application. The objective was to reach a high Output Power associated to a very high Power Added Efficiency. This device uses the 250 nm gate length GaN technology on SiC from UMS (GH25-10). To combine a high level of output power and a very high PAE, a harmonic tuning of the load and source impedances has been necessary. The MMIC, characterized in CW mode and biased in class A-B, achieves better than 20 W of Output Power (Pout) associated to a PAE above 50 % and a Power gain (Gp) higher than 19 dB in the full 7.8-8.8 GHz frequency range. This high performance has been obtained in a very challenging environment due to all the constraints from space de-ratings. These results are among the best ones published in terms of PAE and Pout in this frequency range.