I found 03 differents capacitance values of my designed interdigital capacitor from different way.

1- Capacitance extracted from the post processing-network parameters-transmission line;

2- Capacitance extracted from the Y matrix (negative values were found);

3- Capacitance extracted from the Z matrix ;

- Which way presents the capacitance value of the interdigital capacitor?

- Which capacitance should I take (C1-1 or C2-1)?