AMSAT members Allen Katz, K2UYH and Marc Franco, N2UO have
designed a VHF, high-efficiency, class-E, RF power amplifier
with a DC to RF efficiency of 86.8%. Their innovative
design is based on silicon carbide (SiC) metal-semiconductor
field effect transistors, or MESFETs.
The design was presented in a paper at the IEEE International
Microwave Symposium in Hawaii. It is now available on-line:
http://www.cree.com/products/wireless_docs.htm titled
"Class-E Silicon Carbide VHF Power Amplifier" (June 5, 2007)
The final amplifier efficiency was measured at around 86 to 88%
with this number holding quite well at almost any drain voltage
or output power. This type of amplifier is under consideration
for the envelope elimination and restoration linear amplifier
planned for the AMSAT Eagle satellite.