Conductivity Measurement Technique for Interface and Surface Using Dielectric Rod Resonator Based on Calibration

A measurement method for the conductivity of circuit substrate was proposed based on the calibration of dielectric resonator. This method can efficiently measure the conductor deposition interface conductivity (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sigma _{i}$ </tex-math></inline-formula>) and surface conductivity (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sigma _{s}$ </tex-math></inline-formula>) of a single sample without prior knowledge of its dielectric constant. After calibration, the influence of the sample’s dielectric slab to the interface conductivity measurement is effectively eliminated. This method allows for efficient conductivity measurement of the interface or surface of a single sample at single frequency or multiple frequencies, in one assembly process. A measurement device was fabricated based on this method. Interface and surface conductivity of four different copper-clad substrates, including Rogers RT/duroid5880 and Rogers RO4350B substrates, were measured. The interface and surface conductivity of four samples were measured using another proposed method, and the maximum deviation between the measured results and the results presented in this article did not exceed 5%. By using resonator multimode measurement, we evaluated the performance of the sample interface conductivity at different frequencies during 11.5–26.5 GHz. This technique holds the potential in facilitating the development and practical application of new materials.