Difference between 3D and Plannar for Capacitance Calcualtion

Hi,

For some part of the project i am working on it, i need to calculate the capacitance of an interdigited electrods. I am using quickfield sofware or AWR enviroment design. My procedue is applying some defined voltage, read the stored charge and find the capacitance. Do you think doing this procedure in planar simulation is correct? or i have to do it in 3d? actually my question can narrow down to the fact that what is the difference between planar and 3d simulations?

Thank you in advance

Since your capacitor is planar, a full-wave simulation using 2.5D simulators like Momentum (EM simulator of ADS) is enough.
If by planar simulation you mean 2.5D simulators, then, yes you can do it and expect good accuracy.