Hi,

I would like to model a variable vacuum capacitor (name Cacc2) inserted in a coaxial line in CST Studio Suite  .

The capacitor has a complex geometry so I would prefer to model it by a lumped circuit RLC.

It will be inserted as a serial component of the inner conductor of a coaxial line. It will be surrounded by the outer conductor.
It has a diameter higher than the diameter of the inner conductor and lower than the diameter of the outer conductor.

I do not know how to model it right to get coherent results.
I wonder if I can model the virtual diameter of the discrete capacitor by its parameter "radius", indicating to CST to only simulate EM field out of the cylinder defined by this radius and the length between its two edges?

Below is the existing model in CST :