A new temperature stable microwave dielectric ceramics: ZnTiNb2O8 sintered at low temperatures

Highlights: → The sintering temperature of ZnTiNb2O8-xTiO2 ceramics with BCB was reduced to 950 deg. C. → The τf was modified to 0 ppm/deg. C with reasonably good Q x f and εr. → The εr = 38.89, Q x f = 14,500 GHz and τf = 0 ppm/deg. C were achieved. → It represented very promising candidates as LTCC dielectric materials. - Abstract: The phases, microstructure and microwave dielectric properties of ZnTiNb2O8-xTiO2 composite ceramics with different weight percentages of BaCu(B2O5) additive prepared by solid-state reaction method have been investigated using the X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The results showed that the microwave dielectric properties were strongly dependent on densification, grain sizes and crystalline phases. The sintering temperature of ZnTiNb2O8 ceramics was reduced from 1250 deg. C to 950 deg. C by doping BaCu(B2O5) additive and the temperature coefficient of resonant frequency (τf) was adjusted from negative value of -52 ppm/deg. C to 0 ppm/deg. C by incorporating TiO2. Addition of 2 wt% BaCu(B2O5) in ZnTiNb2O8-xTiO2 (x = 0.8) ceramics sintered at 950 deg. C showed excellent dielectric properties of εr = 38.89, Q x f = 14,500 GHz (f = 4.715 GHz) and τf = 0 ppm/deg. C, which represented very promising candidates as LTCC dielectrics for LTCC applications.