HPM protection of AESA utilising GaN

Purpose and goal

The objective of the project was to investigate the robustness of GaN LNAs when subjected to large input power levels, identify important factors with impact on robustness and develop methods to improve it. The project led to several breakthroughs in the understanding of both robustness and recovery time in GaN LNAs. In particular, trapping effects in the GaN epistructure was identified as a limiting factor for recovery time after a high input power pulse and several optimizations of the fabrication process were shown to be able to mitigate this problem.

Expected results and effects

The improved understanding of recovery time and robustness of GaN LNAs gives Saab improved opportunities to develop sensors with sufficient protection from HPM threats without compromising performance and cost. It also increases our ability to give feedback to foundries about future development of GaN technologies. Saab is an important customer for European GaN foundries, which gives us possibilities to influence future GaN processes towards our needs.

Planned approach and implementation

The project has been a close collaboration between industry and academia with Saab as a requirement specifier and project manager. LiU has contributed with optimization and growth of epistructures. Measurements and studies on failure mechanisms, as well as component fabrication, were done at Chalmers. Design and evaluation of the circuits produced within the project have been done by Saab. The work was conducted with quarterly follow-up meetings.