Influence of water absorption on dielectric properties at high frequencies

Abstract

The performance of printed circuit boards (PCBs) is influenced by the dielectric properties of the insulation layers of PCBs. Especially, the absorption of electromagnetic waves of water becomes very high at around 20 GHz, we measured common dielectric materials used for insulation layers of PCB in K-band (18-26 GHz) after various pre-treatments at high temperature and high humidity. An aramid epoxy composite and polyimide were affected significantly due to their high water absorption rates.