This paper presents a method for measuring the complex permittivity of dielectric material on a dielectric/metal stack. A series of circular capacitor and transmission line test structures are designed and fabricated. The methodology has been verified by measuring the dielectric constant of a known SiO2 layer using Capacitance-Voltage (C-V) measurement and scattering parameter (S-parameter) measurements. The combination of C-V measurement and S-parameter measurement is shown to be suitable for characterization of dielectric material on the complex cross-sections..