ABSTRACT: Achieving high VSWR is crucial at high frequencies since passive interconnects, such as waveguide sections and on-wafer probes, experience higher loss, which reduces the maximum reflection coefficient presented to the device under test (DUT). Noise parameter extraction and load pull require high-VSWR impedance tuners capable of synthesizing various reflection coefficients anywhere on the Smith chart. The Maury Microwave WR3.4, WR4.3, and WR6.5 electromechanical impedance tuners offer the highest VSWR on the market by a significant margin, enabling users to perform active device characterization up to 330 GHz.