Investigation of X-parameters measurements on a 100 W Doherty power amplifier

In this article we describe a high-power reflectometer set-up specifically designed for large-signal nVNA measurements for the extraction of X-parameters. The heart of the measurement set-up is an Agilent N5242A PNA-X in nVNA mode. We have measured a Doherty amplifier constructed from a 2-stage, dual-path RF power amplifier IC. This power amplifier can deliver in excess of 100 W in Doherty mode, and these measurements represent the highest power X-parameter extraction reported to date.