Digital Beamforming with Digital Predistortion using Xilinx RF SoC ZCU216

Abstract

This paper presents the implementation of digital beamforming (DBF) and linearization of power amplifiers (PAs) using Xilinx RF SoC ZCU216 software-defined radio (SDR). PAs in all the transmitting paths are linearized using the Memory polynomial (MP) model of the digital predistortion (DPD) technique to increase PA's efficiency and reduce the overall cost of the beamforming system. This paper also presents the methodology for phase calibration of each SDR transmitter path before applying DPD to provide an accurate phase to each antenna element. A 1x4 uniform microstrip antenna array is designed to operate at 3.5 GHz to perform DBF. The 5G NR signal with 20 MHz bandwidth is used for testing. The experimental results show that the beam is formed in the desired direction as per the applied phase shift between the antenna elements. An ACPR of -48 dB is obtained after DPD in each channel.