Active fixture with passive tuners for full-range load-pull measurements

The lossy cable in a conventional load-pull setup was replaced with an active fixture to realize full tuning range by using passive electromechanical tuners. The approach was validated in small-signal characterization of a through line up to the edge of the Smith chart, as well as large-signal characterization of a heterojunction bipolar transistor up to a voltage standing-wave ratio of 10:1. The approach is simpler than active load-pull setups and it significantly enhances the capabilities of conventional load-pull setups, especially in the characterization of high-power transistors with very low matching impedances.