A method to evaluate effects of moisture absorption on dielectric constant and dissipation factor of printed circuit board materials

In this article a new method to evaluate, effects of moisture absorption on dielectric constant and dissipation factor in function of temperature and frequency are presented. The development of method is based on the experimental measurements and the use of ring resonator structures implemented to FR4-type material. The experimental measurement procedure was carried out at frequency range from 1 GHz to 10 GHz. The used temperature points were 23/spl deg/C and 85/spl deg/C. The results gained by the presented method were observed to be reproducible and consistent with the amount of the absorbed moisture. The method can be applied to different printed circuit board materials.