Effect of CuO additive on sintering and microwave dielectric properties of Ca(Sm_0.5Nb_0.5)O₃ ceramics

Ca(Sm_0.5Nb_0.5)O₃ microwave dielectric ceramics with different contents of CuO sintering additive were prepared by conventional high-temperature solid state method, and the effects of CuO additive on the sintering, structure and microwave dielectric properties of Ca(Sm_0.5Nb_0.5)O₃ ceramics were studied. The results show that the densification of Ca(Sm_0.5Nb_0.5)O₃ grains could be improved and a reduction of sintering temperature (about 200°C) obtained by adding CuO into Ca(Sm_0.5Nb_0.5)O₃ ceramics. At 1350°C for 4 h, Ca(Sm_0.5Nb_0.5)O₃ ceramics with 1.5%(ω) CuO addition possess good microwave dielectric properties, relative dielectric constant ε_r 23.98, product quality and frequency Q×f 27754.5 GHz and temperature coefficient of resonant frequency τ_f -2.7×10^-6°C^-1.