skrf.media.cpw.CPW.ep_re

property CPW.ep_re: Union[numbers.Number, Sequence[numbers.Number], numpy.ndarray]

Effective permittivity of the CPW (also known as Keff).

If the thickness of the dielectric substrate is large, the effective dielectric constant of the even mode can be approx as:

\[\varepsilon_{eff} = \frac{\varepsilon_r + 1}{2}\]

The effective permittivity can be defined as in the case of a microstrip line, that is as the square of ratio of the capacitance per unit length to the phase velocity.