FPGA-based set-up for RF power amplifier dynamic supply with real-time digital adaptive predistortion

This paper presents an exhaustive description of a field programmable gate-array (FPGA) based set-up for envelope tracking and dynamic biasing of RF power amplifiers (PA). The system includes digital adaptive predistortion (DAPD) and gain compensation deployed in a FPGA device. For testing purposes a GaN HEMT RF PA operating at 3.5 GHz was considered. Preliminary experimental results are provided showing the DAPD compensate for the steady-state PA nonlinear distortion arising as a consequence of varying the power supply.