Conformal mapping of the field and charge distributions in multilayered substrate CPWs

Conformal mapping (CM) and partial capacitance techniques are used for analytical evaluation of charge/current and electric- and magnetic-field distributions in a multilayered substrate coplanar waveguide (CPW) in the quasi-TEM approximation. The results, compared with finite-element method simulations, show that the magnetic wall assumed at the dielectric-dielectric interfaces in CM is a good approximation for many practical cases. The method is applied to a CPW with a thin ferroelectric film used in tunable microwave devices.