Stubs length for double stub parallel tuning on Smith Chart

Thread Starter

simozz

Joined Jul 23, 2017
114
Hello,

I was reading the AAC article on stub matching

https://www.allaboutcircuits.com/technical-articles/learn-stub-tuning-with-a-smith-chart/

and I got stuck on the stub lengths at the double stub tuning example.

The author states that L1 = 0.146λ, L2 = 0.204λ or L’1 = 0.482λ, L’2 = 0.35λ.

But how do these value are determines from Smith chart ? I think I understand the way to calculate them for single stubs, but I don't see as the same method works for parallel stubs. Could someone clarify this ?

Thanks.
Regards.
 

Thread Starter

simozz

Joined Jul 23, 2017
114
OK I got it. Just look at the values of susceptance values on complex circunferences and look where these end, there's the wavelength.
 
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