The AMSAT-NA site carries a picture showing the mechanical prototype of the 5.7 GHz Low Noise Amplifier which will be used in the Phase 5 Lunar and Phase 4B Geosynchronous amateur radio satellite projects.
Unfortunately US Federal Government ITAR legislation prevents them disclosing any technical information about it.
The International Traffic in Arms Regulations (ITAR) inexplicably applies to amateur radio satellites. It threatens US radio amateurs with jail terms or six figure fines if they cooperate with amateurs outside the USA on satellite projects. Cooperation includes talking about or publishing on the web certain information regarding amateur radio satellite systems.
The AMSAT-NA 5.7 GHz LNA page can be seen at http://www.amsat.org/?p=5519
5 GHz / 10 GHz amateur radio transponders are planned for the Heimdallr spacecraft expected to launch in September 2018 into a Lunar orbit. Further information is at
ITAR – Section 1248 Report Released
AMSAT Wants Amateur Radio Satellites Off US Munitions List