Markers while using a Smith Chart

[MiOh]

The markers when using a Smith chart are showing polar coordinates, not the actual S-parameter.

The center of Smith Chart is 1 ohm (if normalized) or 50 ohms if using 50 ohm ports (not normalized. The left side is 0 ohms and the right side is infinity.

When using the markers, the center shows zero, the left shows minus one and the right shows plus one. These are normalized polar coordinates.

MiOh

[wb6yaz]

Plotting s-parameter data with a table also shows this error when using real / imaginary setting.

[QucsStudio]

The data in the smith chart is correct. Of course, the markers show the values of the s-parameters and not the corresponding impedances. Therefore the numbers.

Please use the function rtoz(…) to transform reflection coefficient (e.g. S11) to impedance.

[dom]

I also stumbled on this in the past and found it rather surprising. Would it be possible to add a checkbox in the graph properties or something similar to display impedances instead of coordinates? I didn’t even know the rtoz function existed…

[Author]

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