Steven S. Holland » Matlab http://stevensholland.com Sat, 31 Dec 2011 13:50:11 +0000 en hourly 1 http://wordpress.org/?v=3.3.2 Smith Chart Matlab function http://stevensholland.com/smith-chart-matlab-function/ http://stevensholland.com/smith-chart-matlab-function/#comments Sat, 01 Nov 2008 06:04:15 +0000 admin http://stevensholland.com/smith-chart-matlab-function/ Every now and then I write or modify a matlab function that I need for my research, and will post them to this blog here and there, with the hopes that they will be useful to someone doing antenna/microwave design.  I know, there is the Matlab File Exchange (which is very useful!) , but hey, this is my blog, I want to post my content here.

Below is a function I used to plot smith chart results in matlab.  I used basic plotting code to generate the chart itself, and added a simply plot function to add the impedance locus and constant VSWR circles.  Hope this is helpeful!  Please let me know if anyone finds a bug.  I will note that there is no safeguard in the function for s-parameters that are greater than 1, which if you are plotting the active S-parameters of a multiport device, are possible.  This isn’t a big deal when the S-parameter goes slightly above 1, but if it swings well above 1 you end up with a tiny smith chart and these erratic line segments…it’s a mess.  For passive applications I haven’t come across a bug yet.

smithchart.m


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