Open-Loop Active Load-Pull Setup Using the ZCU216 Radio Frequency System-on-Chip

Journal article, 2025

A fully self-contained active open-loop load-pull measurement system based on a commercial radio frequency system-on-chip (RFSoC) evaluation board is presented. The proposed setup eliminates the need for external signal generators and vector network analyzers (VNAs) by leveraging the ZCU216's integrated high-speed DACs and ADCs. A simple and extensible calibration method is introduced to accurately synthesize arbitrary load impedances presented to the device under test (DUT). The system's flexibility is demonstrated through three measurement scenarios: return loss measurements of a 3-D-printed horn antenna and small-signal gain measurements of the commercial RF power amplifier (PA) QPA9501, utilizing the setup as a two-port VNA and active load-pull measurements of the same PA at 5.4 GHz. Measurements agree with E5071C VNA measurements, validating the system's effectiveness and highlighting the potential of RFSoC platforms as cost-effective, reconfigurable alternatives to traditional load-pull instrumentation.