Smith Chart for Viewing User Supplied Impedance / Admittance / Reflection Coefficient Data

Features

• Display a sequence of normalized impedance, admittance or reflection coefficient in a circle of unity radius commonly known as a Smith Chart
• Complex-valued sequences can be entered through the keyboard, or through copy/paste from a opened local text file
• Options of viewing with the impedance chart, admittance chart or both
• Reporting parameters to any data point on the chart

Rules and Theories

For impedance or admittance involving a transmission-line of characteristic impedance Z₀, the mapping of the complex reflection coefficient vs. the complex impedance (Z) or complex admittance (Y) is given by

where the normalized impedance/admittance are defined as

Smith Chart is the most used tool for microwave engineers to visualize complex-valued quantities

and calculate the mapping between them.

The classical Smith Chart, as it is implemented by this applet assumes

The Applet and User's Guide

• Set the characteristic impedance if it differs from 50 ohm
• Entered a sequence of three columned data with first column being either the electrical length (EL) in degrees, or frequency in Hz. The second and the third column are the real and imaginary part of a complex value for one of the three quantities in (1) Z, impedance; (2) Y, admittance; (3) Gamma, the complex reflection coefficient
• Click "Get Data" will cause the applet to read and parse all data points
• Click "Clear" will erase all data
• Click "Init. 1" or "Init. 2" will cause the applet to automatically generate a sample input data sequence
• A click on "Z Chart", "Y Chart", or "Z&Y Charts" causes the applet to display the impedance, admittance or both grids
• A drag on the slider will cause a marker to move with the plotted data points. In the mean time, the output reporting area shows the parameters that are related to the point selected

References

Phillip H. Smith, "Electronic Application of the Smith Chart", Noble Publishing, Atlanta, 1995.

A color Smith Chart in PDF format