Sintering behavior, phase evolution and microwave dielectric properties of thermally stable (1−x)Li3NbO4−xCaTiO3 composite ceramic

Abstract

Microwave dielectric ceramics with the composition of (1− x )Li 3 NbO 4 − x CaTiO 3 (0.1 ≤x≤ 0.3) were prepared by the solid-state reaction method. The sintering behavior, phase structure, and microwave dielectric properties of (1− x )Li 3 NbO 4 − x CaTiO 3 ceramics were investigated. The samples consisted of Li 3 NbO 4 and CaTiO 3 phases, and the amount of CaTiO 3 phase increased with increasing x . The microwave dielectric properties of the sintered ceramics varied with increasing CaTiO 3 content. In particular, the temperature coefficient of resonate frequency values ( τ f ) can be adjusted to near-zero. Typically, 0.15 mol CaTiO 3 added 0.85Li 3 NbO 4 –0.15CaTiO 3 ceramic exhibited good microwave dielectric properties with a relative permittivity of 21.9, a Q × f value of 24,900 GHz, and a τ f value of 5.6 ppm/°C. These results indicate that 0.85Li 3 NbO 4 –0.15CaTiO 3 ceramic can be a candidate in microwave dielectric resonators.