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New for September 2026. In this example we will try to improve the match of a specific amplifier over a specific bandwidth using QuickSmith. If you want to follow our example, the S2P data we used can be downloaded here. You might have to right-click and "save link as" to get the S2P file.
Download example amplifier data here
Now, go to QuickSmith.online, pull down the "Data"tab and click the "Open Measurement" to pull in the data.
QuickSmith will ask you "what should it be" and you need to answer "Load". Note that QuickSmith only uses S11 in an S2P file to do its magic. It would be nice if it gave you an S22 option...
The S2P file's S11 data is displayed over the full bandwidth. Our data file spans roughly 9 to 12 GHz, we purposely selected these data from a wideband measurement because we didn't want to look at all the data outside of our selected band. The cursor is what QuickSmith uses to generate matching networks and defaults to the lowest frequency in the data. We moved it to 10.5 GHz by typing 10500 into the (MHz) frequency box. We also displayed a 2:1 VSWR circle on the chart. None of the S11 data is inside the circle. This amplifier needs some love...
Now let's use QuickSmith to generate a two element matching network to center 10.5 GHz at 50 ohms. A series inductor and shunt cap puts 10.5 GHz to a perfect match. But part of the band is way outside the 2.0:1 circle. That's no bueno.
Next, let's look at the Broadband match option. Click it and you will see several bandwidth options. We selected the full bandwidth (which is the default).
After a few seconds (tihs step is NOT instantaneous!) QuickSmith will generate a list of options for a broadband match. You will need to scroll down the window to see all the options.
We applied the first matching nettwork, which includes a shorted stub, a series line and another shorted stub. Check it out, the entire band is well inside the 2:1 VSWR circle!
QuickSmith is a useful tool for exploring matching network options, quickly. If you have suggestions for making the tool more useful or to fix bugs, send feedback to the QuickSmith website, under the "Help" tab.
Enjoy!