An accurate method for measuring the dielectric constant of printed wiring board materials

A new time‐domain reflectometry measurement method is described that provides accurate measurements of the average high‐frequency (0.1GHz ‐ 10GHz) dielectric constant of printed wiring board materials and is suitable for “factory floor” use. A parallel‐plate transmission line is used for the sample geometry. Only simple numerical processes are required to extract the characteristic impedance and dielectric constant of the sample from the acquired data. The long‐term measurement reproducibility and short‐term measurement repeatability of the method are described.