Microstructure and microwave dielectric properties of (1−x)Ca0.6La0.267TiO3–xCa(Mg1/3Nb2/3)O3 ceramics

Abstract (1 − x )Ca 0.6 La 0.267 TiO 3 – x Ca(Mg 1/3 Nb 2/3 )O 3 ceramics were prepared by a conventional solid-state ceramic route. The microstructure and microwave dielectric properties were investigated as a function of composition and sintering temperature. As the content of Ca(Mg 1/3 Nb 2/3 )O 3 increased, the temperature coefficient of resonant frequency ( τ f ) value decreased gradually. By appropriately adjusting the x value in the present ceramic system, a near-zero τ f value could be achieved. The appropriate increase of sintering temperature could significantly improve Q · f value by influencing the grain growth. The optimal microwave dielectric properties with a dielectric constant ( ɛ r ) of 52.4, Q · f of 36,428 GHz (at 5.8 GHz), and τ f of 3.4 ppm/°C were obtained for the specimen 0.5Ca 0.6 La 0.267 TiO 3 –0.5Ca(Mg 1/3 Nb 2/3 )O 3 sintered at 1490 °C for 4 h.