Extraction of the Complex Permittivity of PCB

With the increase of the system working frequency, there is a great demand for the signal integrity of PCB (Printed Circuit Board). There are various types of PCB substrates on the market. These substrates show different electrical properties and uncertainty, due to the differences in composition. The values of DK (dielectric constant) and DF (dissipation factor) of a practical PCB are usually different from their nominal values form the vender. Therefore, how to accurately extract the values of DK and DF has always been a hot research topic. In this paper, we verify the accuracy of the proposed extraction method, which is using two stripline traces with different lengths. Both numerical and measurement results are provided to verify the accuracy of the proposed method.