Combined Wideband Active Load-Pull and Modulation Distortion Characterization with a Vector Network Analyzer

We present a demonstrator set-up for amplifier error-vector magnitude (EVM) characterization in the presence of wideband load termination arbitrarily set by the user through active modulated signal injection. In the proposed implementation, both the EVM characterization and the wideband active load-pull (WALP) technique are solely based on iso-frequency ratioed measurements obtainable with legacy vector network analyzer (VNA) technology. By avoiding broadband signal demodulation, this approach allows to remove any receiver bandwidth limitation, thus enhancing measurement accuracy and enabling realistic modulation distortion assessment across arbitrarily-wide test bandwidths. The method is tested on a packaged power amplifier circuit for 5 and 30 MHz modulation bandwidths around 1.2 GHz.