Select the "Delimited" option, then click "Next." Set the window to display "All Files (*.*)," since the S‑parameter file will most likely not end in an Excel extension. Click the "File/Open." menu selection and locate the S‑parameter file to be plotted (in this case, “23212725.s2p”).Experienced Excel users might want to skip down to the image loading and calibration section. Here are step-by-step instructions for generating your first Smith Chart. A copy of the datasheet Smith Charts are given for results comparison. All that is required is an accurate graphic of a Smith Chart for use as the chart background image, and a rectangular‑to‑cylindrical coordinate conversion.Īlthough the example given here is used to plot S‑parameters from a file, the possibilities are great for generating any sort of Smith Chart application such as for impedance matching.Ī general-purpose amplifier (RF2321) manufactured by RF Micro Devices is used in this example, and its S-parameter file was downloaded from the RFMD website. This article describes an extremely simple method of implementing a Smith Chart using the built‑in graphing capability of any modern spreadsheet program (Excel is used in this example). If a Smith Chart is included in a spreadsheet, it is usually an image pasted in from some other application. If you appreciate the effort it took to develop this workbook, please consider making a donation to RF Cafe by clicking here (at the bottom of the list).Įngineers use spreadsheets for a myriad of applications from calculating cascaded chains of components to PLL phase noise prediction, but I can never recall seeing S‑parameters plotted in a spreadsheet using a Smith Chart 1. Finally, click here if you would like a fully-detailed Smith Chart, created in Visio, with impedance and admittance lines.
Click here to download just the background Smith Chart graphic. Click here to download the example workbook. Step-by-step instructions are presented below. Version 2.1 corrects a graphical equation, but does not affect the accuracy of the previous versions (thanks to Peter for alerting me). Version 2.0 adds equivalent denormalized impedance with equivalent resistance and capacitance/inductance values. The workbook shown below used data imported from a typical S-parameter file (in this case an RF2321 amplifier, from RF Micro Devices) and plotted on a chart that uses an image file that contains a Smith Chart. This example Excel workbook demonstrates how easy it is to implement a Smith Chart using only a standard x-y scatter chart and coordinate conversions. The original Smith Chart for Excel that takes s-parameters as input is detailed below. If you download the new edition, you will need to enable the Analysis ToolPak (included with Excel as an Add-In) to perform the complex math. A modification to the original Smith Chart for Excel permits doing so. Please use Chrome or Firefox, or, send me an e-mail)Ī situation arose at work where we needed to be able to plot complex impedance points taken off the network analyzer display and plot them on a Smith Chart. (Note: IE8 sometimes has problems with the ZIP. New Edition Allows Entering Complex Impedance Values Rather Than S-Parameters