VNA-based broadband EVM measurement of an RF nonlinear PA under load mismatch conditions

In the context of modern communications systems operating at radio-frequency (RF), the error vector magnitude (EVM) is the most commonly adopted metric to quantify modulation distortion caused by a nonlinear device. While EVM is typically measured with instrumentation featuring broad acquisition bandwidth (BW), here we implement a method based on multiple narrowband vector network analyzer (VNA) acquisitions, allowing for improved measurement accuracy and for broader characterization BWs. We report the EVM characterization of a nonlinear RF power amplifier (PA), analyzing, in particular, the case of the PA cascaded with a linear network, under load mismatch conditions as imposed by a narrowband passive tuner.