Q factor of 2-port inductor?
How can I calculate the Q factor of non-symmetric 2-port inductor from the S-parameter information ?
What does it mean ' non-symmetric' ?
Generally an inductor is characterized with 2-Port illustration as follows.
>-----<Inductor>------->
Port-1 Port-2
>-------------------------> ( GND)
If it's you have meant , after obtaining S-parameters , in a simulator , these S-parameters are put in a black-box and second port is grounded. In this case a S-parameter simulation is done and Z-Parameters are obtained. Then ,
L= imag( Z11)/( 2*pi*freq)
Q=imag( Z11)/re(Z11)
are calculated.
Rgrds
non-symmetric means S11 is not the same as S22, as the physical structure itself non symmetric.
Would it give the same result if port-1 is grounded ?
hi, BigBoss,
I assume your Z11 is single-ended, where the second port is terminated to ground (as you mentioned). However, the s-parameter are obatained by termination of 50 Ohm. Hence, convertion should be done?
I used @ds, am I right to convert the s-parameter to y-parameter and than calculate its L and Q? In this case, only math is performed, instead of simulation. But, I doubt about how accurate with this method.
When you do a simulation and obtained S-parameters , these will be normalized to 50 Ohm s-parameters. Therefore termination impedance is not important in this case. Conversion is not neccesary because when you've obtained s-parameters , simultaneously you have obtained z-parameters regarding to s-parameters.
Generally 2-port networks is considered differential. But if one port is grounded this is converted 1-port circuit.
You can consider this structure as a Resistance in series with a ideal inductance. What becomes when second port is grounded ? This circuit will behave a single non-ideal inductance.
This method works well and proven. However it's possible to use modeller of ADS2003A , it gives the same result.
Rgrds