LAUSR

Abstract In this study, (1-x) ZnTiNb2O8-xCuTiNb2O8-0.4 wt%LBSCA (0 ≤ x ≤ 0.4) microwave dielectric ceramics prepared by solid-state sintering were investigated to obtain low-temperature co-fired ceramic (LTCC) materials with near-zero resonant frequency temperature coefficient. X-ray diffraction (XRD) pattern and Rietveld refinement results reveal that with the increase in x value, main phase of ceramics is transformed from ZnTiNb2O8 to ZnNb2O6 and new phases (CuTiNb2O8 and Ti3O5) are formed at x ≥ 0.3. The microwave dielectric properties are affected with the appearance and increase in content of the secondary phase. Scanning electron microscope (SEM) images indicate that sample grains are relatively uniform and dense at x = 0.2. Raman shift obtained from Raman spectra explain changes in dielectric constant. Results reveal that the desirable dielectric properties were obtained by sintering at 875 °C with x = 0.375: e r = 35.01, Q × f = 19449 GHz, and τ f = -0.3 ppm/°C, and the highest Q × f value (~38711 GHz) was obtained by sintering at 900 °C with x = 0.2 in the study.