In this article, there is a section that models the capacitance of a via.
The equation given is:
$$C=\frac{(0.55\epsilon_rTD_1)}{D_2-D_1}$$
Where T is the board layer thickness, D1 is the pad width and D2 is the clearance hole.
In the article \$\epsilon_r\$is said to be the relative permeability. Is this a misprint? I thought that refers to the permittivity.
Doesn't permeability refer to the magnetic field? I would assume that the capacitance would be related to the electric field.