A 14 W wideband supply-modulated system with reverse buck converter and floating-ground rf power amplifier

This paper presents a wideband supply-modulated system with a floating ground RF power amplifier and a reverse buck topology DC/DC converter. The power amplifier and the reverse buck converter are based on microwave GaN technology. The system is operating at 1620 MHz and 40 V supply and shows 39% overall power-added efficiency at an average output power of 14.6 W for an 8 MHz OFDM modulated signal with 8.6 dB PAPR. The implemented floating-ground RF power amplifier accommodates signals with up to 40 MHz bandwidth. The reverse buck converter switches at 45 MHz with a PAE of 80–91% over duty cycles from 40–100% equivalent to supply voltages of 16–40 V. For the first time a reverse buck topology system enabling GaN switching operation referred to ground is shown in dynamic operation with performance similar to or exceeding classical systems.