A high improved quality factor of Li2MgTi3O8 microwave dielectric ceramics system

Abstract SnO 2 -doped Li 2 MgTi 3 O 8 ceramics were successfully synthesized by a solid-state method. The effects of SnO 2 addition on the microstructure and dielectric properties of Li 2 Mg(Ti 1− x Sn x ) 3 O 8 ( x =0.10–0.25)were investigated. Microscopic analysis showed that two phase composition regions were identified in the specimens sintered at 1100 °C; [spinel+rutile] at 0.10≤×≤0.15, and [spinel+rutile+ilmenite] at 0.20≤×≤0.25. As SnO 2 concentration increased, the temperature coefficient of resonant frequency( τ ƒ ) and dielectric constant( e r ) decreased, which was strongly correlated with the phase composition. However, the quality factor ( Q × ƒ ) significantly increased with SnO 2 content due to the increase of grain size. Especially, the Li 2 Mg(Ti 1− x Sn x ) 3 O 8 ( x =0.15) ceramics sintered at 1100 °C for 4 h exhibited good microwave dielectric properties: e r =26.0, Q × ƒ =74,700 GHz and τ ƒ =−5.2 ppm/°C.