Dielectric characterization of printed circuit board substrates

The design and quality assurance of high-speed digital systems require a fast and accurate method for the electrical characterization of printed circuit substrates. A novel technique is presented for measuring the dielectric properties of such substrates based on the measured scattering parameters of a transmission line. The method is broadband, determines the effective permittivity and loss tangent, and is compatible with existing substrate quality assurance schemes. Comparisons with alternative permittivity characterization techniques are presented. Results of this technique compare favorably with those of the coaxial reflection and strip resonator methods.>