EM Similation of MIM Caps

I have a question regarding how to EM simulate mim caps.

I want to see the effect of the bottom plate capacitance to ground in the path underneath my component.

It is a mm-wave amplifier design but in general I can use it for analog design as well.

I want to check the model components from the kit.

How would I go about this ?

I am using Cadence/ADS flow.

Thanks.

What is your technology?

I have been working on EM simulation of MIMCAP in IHP BiCMOS technology, to generate a mm-wave model for the design kit
https://ieeexplore.ieee.org/document/7839730/
and spent some time on modelling the vias in small groups that represent the distributed nature of the via, with z-directed current only, but don't require excessive mesh.

Via currents: In Momentum, set the via currents inside the MIM to 2D model (default is 3D), to prevent unrealistic x-y current in merged vias.