High power effects in gallium nitride-based microwave and RF control devices

Gallium nitride-based HEMTs have been studied in a microwave and RF control application under high power levels. A theoretical model is presented showing an increase in the microwave resistance occurs at power levels greater than +20 dBm due to operation near the current saturation region. This phenomenon is primarily due to the field-dependent mobility in the two dimensional electron gas and is verified with on-wafer experimental data.