Microwave dielectric properties of (1−x)ZnAl2O4–xCaTiO3 compound ceramic with controlled temperature coefficient

Abstract In this study, microwave dielectric properties of (1− x )ZnAl 2 O 4 − x CaTiO 3 samples with controlled temperature coefficient feature are analyzed. The crystal structures of all the compositions were refined by X-ray diffraction. A homogeneous distribution of cations within instrument sensitivity in all the samples was observed using scanning electron microscopy, coupled with energy dispersive X-ray analysis. ZnAl 2 O 4 and CaTiO 3 could coexist when the x content was less than 0.1, whereas Al 2 O 3 and Ca 3 Al 2 O 6 phases were observed in composite ceramics. As expected, the dielectric constant ( e r ) of the composite ceramics increased with the increasing x content, and the quality factor ( Qf ) generally decreased with increasing x -content because of the low Qf of the CaTiO 3 phases. The temperature coefficient of resonant frequency ( τ f ) could be controlled by varying the CaTiO 3 content and could lead to zero τ f value. The 0.92ZnAl 2 O 4 −0.08CaTiO 3 ceramic exhibited e r of 10.8, Qf of 32,300 GHz, and τ f of 0 ppm/°C.