High-Q microwave dielectric properties of Li(Zn0.95Co0.05)1.5SiO4 ceramics for LTCC applications

This study investigated the effects of Li2O-MgO-ZnO2-B2O3-SiO2 (LMZBS) glass on the microstructure, sintering behaviour and microwave dielectric properties of Li(Zn0.95Co0.05)1.5SiO4 ceramics. Li(Zn0.95Co0.05)1.5SiO4 powders were synthesised by a traditional solid-state route and added with different amounts of LMZBS glass (0-4 wt%) to decrease the sintering temperature of the ceramics to approximately 900 °C. The XRD patterns showed that no chemical reactions occurred between the Li(Zn0.95Co0.05)1.5SiO4 ceramics and the LMZBS glass within the doping range. The SEM images indicated that the sample added with 1.5 wt% glass and sintered at 900 °C exhibited a compact and uniform microstructure. In particular, the microwave dielectric properties of the products were related to LMZBS glass content and sintering temperature. The sample with 1.5 wt% LMZBS glass exhibited excellent microwave dielectric properties, namely, εr=6.12, Q×f=83,600 GHz and τf=−39.1ppm/℃.