100-MHz GaN-HEMT Class-G Supply Modulator for High-Power Envelope-Tracking Applications

In this paper, a highly efficient class-G supply modulator targeting high-power wideband envelope tracking applications is presented. The maximum output power using a 50% duty cycle at 100-MHz switching frequency is 62 W for a switching between 30 and 50 V delivered in a 25-Ω load. The modulator including its driver circuit reaches an overall efficiency in the range of 97%-88% for switching frequencies from dc to 100 MHz for passive loads in a wide range. The modulator is designed to operate at various supply voltage levels and is evaluated within the range from 20 to 50 V while powering loads from 25 to 100 Ω. The modulator is characterized in terms of efficiency, switching frequency, and nonlinearities.