High quality factor microwave dielectric diopside glass-ceramics for the low temperature co-fired ceramic (LTCC) applications

Abstract In the present work, microwave dielectric properties of CaO-MgO-SiO2 glass-ceramics based on the stoichiometric composition of diopside (CaMgSi2O6) were accurately investigated. The initial glass was prepared utilizing conventional melt quenching technique. Thermal properties of the milled glass particles were monitored by differential scanning calorimetry (DSC), dilatometry and hot stage microcopy (HSM). Glass-ceramic specimens were prepared through simultaneous one-step sinter-crystallization procedure. In order to achieve high quality factor (high-Q) microwave dielectric properties, glass-ceramics were also prepared through two-step sintering technique. The crystallization behavior of the heat treated specimens was examined by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Based on the obtained results, diopside precipitated as the only crystalline phase in all sintered glass-ceramics. Diopside glass-ceramics sintered through one-step (at 925 °C for 4 h) and two-step (at 800 °C for 4 h, then followed by heating at 950 °C for 2 h) procedures exhibited high-Q microwave dielectric of 56,952 GHz and 64,524 GHz, respectively. The degrees of crystallization and crystallite sizes of the glass-ceramics prepared from both sintering procedures were also characterized.