Constant VSWR testing

[Christos]

iTuners allow constant VSWR testing using appropriate commands, like VSWR_AUTO, VSWR_DO360 etc. These commands use the iTuner's Impedance Synthesis capability to generate, using standard tuner calibration files, a constant VSWR pattern at any given frequency. Typical accuracy of this routine at VSWR=20:1 is around 5%, corresponding to a Gamma of 0.905 and a Gamma error of ~0.01.

For applications where this is not sufficient we have developed a new calibration routine, VSWR+; it uses a fast gradient convergence algorithm, which measures the VNA and corrects the tuner position to get to the target VSWR with a higher precision.

Typical accuracy of VSWR+ is better than 0.5% at VSWR=20:1 (Gamma=0.905; Delta Gamma=0.004) and 5% at VSWR=50:1 (Gamma=0.961; Delta Gamma=0.0018). (Please note that all % errors refer to VSWR and not to Gamma)

Typical duration of this routine depends from the number of angle points and varies between 5 and 10 minutes per frequency.
The routine can handle "on-line embedding", meaning it can create an accurate VSWR pattern also using S2P data from later to include test fixturing.
Two examples are shown below, measured using an iCCMT-708 at 3GHz, tuned for high reflection.