Application of GaN FET in 1MHz large signal bandwidth power supply for radio frequency power amplifier

In this paper, implementation and testing of non-commercial GaN FET in a simple buck converter for envelope amplifier in ET and EER transmission techniques has been done. Comparing to the prototypes with commercially available EPC1014 and 1015 GaN FETs, experimentally demonstrated power supply provided significantly better thermal management and increased the switching frequency up to 25MHz. 64QAM signal with 1MHz of large signal bandwidth and 10.5dB of Peak to Average Power Ratio was generated, using the switching frequency of 20MHz. The obtained efficiency was 38% including the driving circuit and the total losses breakdown showed that switching power losses in the FET are the dominant ones. This implies that minimization of the gate charge is the key issue in the optimization of the device for this kind of application.