Calculating capacitance with on HFSS capacitor model

Hello,

I'm having problem with calculating the capacitance of a capacitor that i designed in HFSS (i attached the simulation).
I measured the im{Z21} parameter and calculated the C with : C=-1/(2*pi*f*im{z21}.
When I calculated the approximate C with C=epsilon*d/A i got about 5pF, but with the second formula i get Farads!

What Should I do?

P.S I'm not sure that the the ports i used are correct.

Hello,

The way you defined your ports is wrong. A lumped port along with its integration line can be defined between a ground line (Lower metal) and a signal line (upper metal). When you do this properly you will get the value of capacitance in both cases equal to approximately 0.55pF. Attached please find the HFSS file.

Thanks,
Hema Swaroop

RFCapacitorPortsChanged.zip