Abstract: A dense lead-free glass ceramic that has low dielectric constant and low dielectric loss for producing high-frequency ceramic devices, such as inductors and low temperature co-fired ceramics (LTCC), is disclosed. The glass ceramic consists of 15-35% by weight of lead-free borosilicate glasses with low softening point, 15-35% by weight of lead-free borosilicate glasses with high softening point, 20-80% by weight of combination of amorphous and crystalline SiO2-filler (preferably 5-30% by weight of amorphous SiO2, 10-50% by weight of crystalline SiO2) and 0.1-10% by weight of at least one oxide of Al2O3, BaO, Sb2O3, V2O5, CoO, MgO, B2O3, Nb2O5, SrO and ZnO. The glass ceramic can be densified up to 99% of its theoretical density after firing and is co-firable with conductive metals between 800-900° C. The dense glass ceramic has dielectric constant of 4.2-4.6 and loss tangent (tan ?)<0.0025 at 20 MHz and good thermal/mechanical strength for application in high frequency electronic devices.

Abstract: A dense lead-free glass ceramic that has low dielectric constant and low dielectric loss for producing high-frequency ceramic devices, such as inductors and low temperature co-fired ceramics (LTCC), is disclosed. The glass ceramic consists of 15-35% by weight of lead-free borosilicate glasses with low softening point, 15-35% by weight of lead-free borosilicate glasses with high softening point, 20-80% by weight of combination of amorphous and crystalline SiO2-filler (preferably 5-30% by weight of amorphous SiO2, 10-50% by weight of crystalline SiO2) and 0.1-10% by weight of at least one oxide of Al2O3, BaO, Sb2O3, V2O5, CoO, MgO, B2O3, Nb2O5, SrO and ZnO. The glass ceramic can be densified up to 99% of its theoretical density after firing and is co-firable with conductive metals between 800-900° C. The dense glass ceramic has dielectric constant of 4.2-4.6 and loss tangent (tan &dgr;)<0.0025 at 20 MHz and good thermal/mechanical strength for application in high frequency electronic devices.