Note: This version of QuickSmith is no
longer available; the website disappeared. Instead, click here for a very nice Web-based version
of QuickSmith, by
There's a new online interactive Smith chart s-parameter plotter in town, and it goes by
the name of QuickSmith. Justin
Coulston, designer of QuickSmith, sent me an e-mail asking that I take a look at it. I did,
and I like what he has done. Assuming that anybody reading this is already at least somewhat
familiar with the Smith chart, this
report will concentrate on the features of QuickSmith. Keep in mind while checking out QuickSmith
for yourself that it is still in Beta phase, so your feedback to Justin will be appreciated.
screen shot is provided below. QuickSmith takes as an input standard format
SnP s-parameter files and plots them on the graph. 'n' is the number of
ports, so S2P would be a 2-port s-parameter file. A reliable source for example
is MiniCircuits. Click the 'Browse' button to select your SnP file, and then select which
s-parameter data to plot (S11 or S22 available for the ERA-1 amplifier,
for example). 'Sample 1' and 'Sample 2' data files are provided by QuickSmith for experimentation
with the program's settings.
QuickSmith Online Interactive Smith Chart Plotter screen shot.
In the upper right corner of the screen are 'Export' and 'Help' buttons. At this time 'Help'
does not appear to be implemented; however, you can go to http://www.engineerrf.com/getting-started
(the 'www.' part of the URL is required as of this writing)
for a brief introduction. Clicking the 'Export' button opens a window to allow printing the
Smith chart display to either a PNG or PDF file. A QuickSmith Forum has been started for user
interaction (a good place to provide feedback).
Three levels of detail are available for the Smith chart background format: Simple, Detailed,
and Super, along with an option to display admittance circles. A couple notes are in order
about setting the display parameters. There is a 'Chart Size' parameter that can be set between
50 and 1000. I did not check QuickSmith on a cellphone so maybe smaller values like 50 are
needed there, but on a desktop, it is too small. A setting of 1000
(or anything >500) produces a display that is the same size on the screen as the
500 size setting, but the circle labels and line thicknesses are smaller (see the two screen
shots below). I don't know if that is the planned use of sizes above 500, but it is useful
for controlling line thickness.
QuickSmith 'Simple' display with Chart Size of 500 - the default.
QuickSmith 'Simple' display with Chart Size of 1000 - note thinner lines
and smaller labels.
One way to get a larger Smith chart display and increase cursor position accuracy is to
use the browser's magnification feature (see screen shot below). Cursor resolution remains
the same, but it is easier to see where it lies in the Smith chart. The cursor position's
complex impedance is displayed dynamically as it moves. I could not find a way to display
admittance values, even with turning off the impedance circles.
QuickSmith 'Super' display magnified at 180%.
QuickSmith 'Detailed' display using the 'Line Opacity' value to deemphasize
the Smith chart background circles.
That covers the basic features of QuickSmith. It promises to be a very useful tool both
in its present form and once planned improvements are implemented. Thanks to Justin for investing
time to make it available.
Posted January 4, 2016