How to calculate the Q factor from the s-parameters ?

[magneto_cool]

Q factor

Hi,

May i know how do i compute the Q-factor for a capacitor or inductor from the S-parameters measured.

Any help will be much appreciated

Thank You

Regards

 

[sergio mariotti]

Q factor

sure!
1st you should know if spar are measured as 2 port or 1 port.
2nd put the spar file into a simulator, if 2 port, short to gnd the out port.
3rd plot Real and Immaginary part of input reactance vs Freq.
4th compute Q= |jX|/R

5th note that for spar measured near external Smith Circle, the accuracy of the calculated Q is poor or bad.