Smith Chart Reading
Smith Chart Reading
(OP)
Hi,
I have a smith chart measurement of input impedance and I'm not sure how to read it. It's for a 2.4 Ghz patch antenna. Any help of resources would be appreciated. Photo attached.
I have a smith chart measurement of input impedance and I'm not sure how to read it. It's for a 2.4 Ghz patch antenna. Any help of resources would be appreciated. Photo attached.





RE: Smith Chart Reading
RE: Smith Chart Reading
On your plot, the two points along the outer edge are at + and - infinity ohms (more or less). They're not resonant frequencies and are certainly not of any practical use unless you're trying to make a quarterwave conductive 'insulator'.
If you want to know the frequencies of each point on the Smith chart, then you need to have the software that produced the Smith chart annotate it with frequency information. If that's not possible, then you need to examine the same data in tabluar format with the frequency as an index column.
RE: Smith Chart Reading
You can also tell something about the bandwidth. If you draw a straight line between where the curve crosses over itself and the origin, find the center of that line and draw a +45 and -45 degree line, that shows you where the bandwidth (3 dB down points) are in frequency. Another way would be to plot that reflection coefficient curve on a linear frequency log amplitude rectangular plot, and the bandwidth is where the S11 magnitude drops 3 dB from the most negative value.
www.MaguffinMicrowave.com
Maguffin Microwave wireless design consulting
RE: Smith Chart Reading
That's neat trick on the Smith Chart! Where did you learn that one?
Z
RE: Smith Chart Reading
www.MaguffinMicrowave.com
Maguffin Microwave wireless design consulting
RE: Smith Chart Reading
http://ww
www.MaguffinMicrowave.com
Maguffin Microwave wireless design consulting
RE: Smith Chart Reading
Z
RE: Smith Chart Reading
Pretty amazing in the last 30 years . Its even affordable !
Cheers Guys , enjoying the memories