The capacitive equivalent circuit and the modal equivalent lengths of the symmetric broadside coupled microstrip open-end discontinuity are calculated in the case in which the conducting strips are embedded in a multilayered dielectric medium. The Galerkin method in the spectral domain is applied to solve the excess charge densities existing on the conducting strips of the discontinuity both in even and odd modes of excitation. Results are presented for broadside coupled microstrip open ends in conventional, suspended and inverted configurations.