Emulation of Nonlinear Dynamics of RF Power Amplifier on FPGA

This paper presents a flexible field-programmable gate array (FPGA)-based emulation framework for RF power amplifiers (PAs). Emulation model of RF PA proves instrumental for testing their performance in hardware before manufacturing. It also facilitates faster design and optimization of advanced signal processing algorithms like digital predistortion. The applicability extends to broader use cases such as reconfigurable RF PAs. The proposed framework employs black-box modeling, obviating the need for internal constitution details and relying solely on input and output signal observations. The framework is built in MATLAB/Simulink® environment with HDL Coder tool box due to its parameterizability and flexibility in synthesizing hardware from a Simulink® design. The effectiveness of the proposed emulationframework is evaluated through FPGA emulation of GaN PA modules, namely, QPA2705 and GTRB424908FC/1 respectively on Xilinx Kintex-7® FPGA. Behavioral simulation results show that the performance of PA models having different non-linearity orders and memory depths matches well with that of PA output characterization data in terms of NMSE as well as ACEPR. The emulation model’s validation was performed through an in-depth analysis, encompassing power curves, as well as power spectral density plots. Various models were examined and compared based on their accuracy and hardware complexity. FPGA emulation results for PA are shown to be precisely matching with that of behavioral simulation. Besides, the paper also compares the resource utilization for FPGA synthesis of PA models.