GaN FET-based Class D amps

High-frequency transistors achieve record efficiency at 100 volts

Researchers at the Fraunhofer Institute for Applied Solid State Physics IAF have succeeded in significantly increasing the output power of their GaN‑based high‑frequency transistors for the frequency range from 1–2 GHz: They were able to double the operating voltage of the devices from 50 volts to 100 volts, thus achieving a power-added efficiency of 77.3 percent. This technology allows the development of highly efficient amplifiers with even higher power, as required for applications in the fields of plasma generation, industrial heating, communications and radar technologies.

1: Technics- SE-R1
2: "           "  SU-G30
3: Merrill Element 118
4: "                    "   116
5: AGD Production GaN Tube. 
6: Class D Audio (said they were prototyping)

Cheers George