Inductance of a parallel plate transmission line

I'm trying the find the lumped element parameters of a parallel plate transmission line.

I've been using the "energy method" described on pages 87 and 88 of the AC/DC Module Users Guide.

I used the electrostatics branch to apply a fixed voltage and calculate the lumped capacitance, but I can't figure out which physics under the AC/DC module to use and how to set it up so I can find the magnetic energy density.

Can anyone help direct me in setting up this model?

Thank you.