Does s-parameter relate to dc current or voltage?

On different dc voltage, the s-parameter is different or not? why?

why the s-parameter simulation in @DS's momentum doesn't care about dc voltage?

S parameter analysis is basically small signal ac analysis.
DC need not be considered
thanks

The S parameters are a function of the bias point. Linear small signal simulators treat the transistor as a two port.

The S parameter of any active device depends on its DC condition (bias). Usually the S parameter provided from the active device manufacturer will specify the DC condition.
In ac small signal analysis, we assume the dc condition does not change.

Yes Buta
you are right
In ac small signal analysis, we assume the dc condition does not change.
that is why we do not include DC parameters in analysis
thank you

how i can make a nonlinear model for the bjt,the company dont prove
the model,only datesheet

yes ,when simulate in Sparameter, you should know what bias voltage and current you choiced

what bjt transistor, u can ask at this forum (i asked it before but i didnt get results, mybe u will )

If I got the question correctly, it is about DC conditions in ADS MOMENTUM! Well, there is not any influence of DC bias on simulating EM structures in Momentum, you can change dielectric and metal parameters for linear and isotropic materials. You can not simulate nonlinearities in Momentum!

flyhigh

If designing a spiral inductor using Momentum, i could calculate the L and R of this inductor based on the s-parameter simulated by Momentum.

Could i use this L and R as the parameters of inductor in circuit simulation? It doen't include DC information in L and R.

S parameter analysis is basically small signal ac analysis. egemini's right!

but DC need not be considered , i think not to a nicety. In sumilation ,we need not be considered DC

because S parameter measure to a certainty DC value.
the DC value used in practical cricuit

Hi

For theory about S parameters, there is a very good app. note from agilent :

h**p://contact.tm.agilent.com/data/static/downloads/eng/Notes/interactive/an-95-1/an-95-1.pdf

Replace * with t