Microwave dielectric properties of mixtures of glass-forming oxides Zn-B-Si and dielectric ceramics MgTiO_3-CaTiO_3 for LTCC applications

摘要

Low dielectric constant, low temperature co-fired ceramics (LTCC) using glass-forming oxides (ZnO, B_2O_3 and SiO_2) with/without MgTiO_3-CaTiO_3 have been prepared by conventional solid-state route. The crystalline phases were studied by the X-ray diffraction and microstruc-tures by the SEM techniques. The materials of different compositional ratio were characterized at microwave frequencies. The microwave dielectric properties of the specimens were found strongly depended on the Zn-B-Si ratios. A short-sintering-time formulation containing Zn-B-Si in aratio of 35:25:40 and 15 wt percent CaTiO_3 can possess promising microwave dielectric properties (epsilon_r = 7.05, Q x f= 3500 GHz at 16 GHz, and tau_f=5.93 ppm/ deg C) at 900 deg C for 0.5 h. It shows not only better properties in comparison with commercial ones but also leaves out the prior glass preparation.