DEVELOPMENT OF GLASS-FIBER WITH HIGH DIELECTRIC-CONSTANT

Glass fibers with high dielectric constant have been developed to mini aturize printed circuit beards used at high frequencies. The dielectri c constant of the glass is 11.6 at 1 GHz while that of E glass is 6.7. In the glass composition system, SiO2-CaO-SrO-BaO-TiO2-ZrO2-NbO25, it was found that the NbO25 plays an important role in decreasing the li quidus temperature of the glass, resulting in successful fiber-drawing . Using the above glass composition system, glass fibers consisting of 200 filaments with an average diameter of 8 mu m have been continuous ly drawn from a conventional platinum alloy bushing. This glass fiber was then woven into cloth. Laminates with a dielectric constant of 10. 5 at 1 GHz have been made with glass cloth impregnated with the thermo setting polyphenylene oxide resin and titanium oxide powder, resulting in high uniformity in the dielectric constant.