How can I get ESR of capacitor through s2p file?

This maynot be an analytic solution. But may be fast enough.
Draw a model of the capacitor in the ADS, which is an ideal capacitor in series
with a resistor (=ESR).
Now put this in the 2-port network, which will look like:

TERM - CAPACITOR - RESISTOR - TERM

Simulate and optimize the R value until you get a similar S2P response.

What do you think?
S.H. Woo

This is a good method for me.
Why is the ideal capacitor series with R and C ?
I thought it should be paralle with R and C.
What is the range of ESR ?

THX a lot

Non-ideal capacitor loss can be represented by either parallel or series
resistance. But, ESR is, by definition, equivalent series resistance.
Think of it this way.
Capacitor A: Ideal (no loss) 100pF capcitor is shunted by 1000Kohm.
Capacitor B: Ideal (no loss) 100pF capcitor is shunted by 100 ohm.

You will understand that Capacitor A is much better than B.

Capacitor C: Ideal 100pF is in series with 1 ohm.
Capacitor D: Ideal 100pF is in series with 100 Kohm.

You will understand Capacitor D is very poor, almost "non-capacitor".
Many LCR meters have options to select between parallel equivalent
and series equivalent.
I hope this helps.
S. H. Woo

I think shwoo has a very good idea about using the ADS s-parameter simulator.

MoonShine