K-band GaN power HFET´s with 6.6 W/mm CW saturated output power density and 35% power added efficiency at 20 GHz

AlGaN/GaN heterostructure field effect transistors (HFET´s) grown on SiC substrates are currently the most powerful three-terminal microwave solid state devices. While the power performance of these devices is well documented at X-band frequencies, there is growing interest in these devices at higher frequencies. In this study we characterize the power performance of GaN HFET´s at 20 GHz. Our results clearly show that GaN HFET´s have strong potential for power applications at K-band frequencies and beyond.