So I was sitting in front of the TV tonight and after a few comments about the show on TV I was banished to my shack. I started to read a few application notes on transistor matching and working the examples up in the smith chart to make sure I was getting the hang of how to use the Iowa Hills Smith Chart software. It dawned on me that I had not described how to determine if the matching network was suitable for the range of intended frequencies.
This is really easy and full credit to the author. Once we have our matching network at the design frequency we can select the option to "Sweep SC" on the right hand edge of the window and a black line shows how the load is transformed as the frequency is swept according the the span setting. I got the following:
Which intuitively is better than a big black line but by how much? Click on the Return Loss button and you get:
Which shows the return loss over the transmitting frequencies will be better than 20dB ie a good match
I can't wait to smoke test this!
73's
Richard
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