Sonnet -- Finding Capacitance between two conductors surrounded by ground plate

Hi all,

How could I simulate the Capacitance between two conductors surrounded by a huge ground plate? Are there any relevant examples you know?

The two conductors are on the same layer, on top of 1000microns of Aluminium Oxide. I surrounded the objects by a large(~3 radius of the object) aluminium plate and connected the plate to the sidewall. I don't know where shall I put the ports on the two conductors and what kind of ports should I put.

I tried to just use co-calibrated ports(port 1 & port 2 respectively) for the two conductors. But the simulation results keep giving me negative capacitance between two ports, why would that happen?

Thanks for answering!