Zplots is an Excel application that allows you to plot impedance and related data obtained from a variety of sources. You can plot on both an XY chart and a Smith chart as well as view the data in tabular format. The XY chart can be customized with your choice of trace lines. Frequency (in MHz) is always shown on the X axis.
What's new in this version:
Version 2.0 added to measure "Measure Transmission Line Parameters" and plot various items related to transmission lines.