A novel LiNb0.6Ti0.5O3 microwave dielectric ceramic with Ca substitutions

Abstract A novel microwave dielectric ceramic LiNb 0.6 Ti 0.5 O 3 (LNT) with Ca substitutions LiNb 0.6 Ti (0.5−x) Ca 1.231x O 3 was synthesized by solid-state method. It was found that with Ca substitutions, the temperature coefficient of resonant frequency τ ƒ could be adjusted to zero, due to the appearance of the second phase Ca 5 Nb 4 Ti 3 O 21 . The τ ƒ of the Ca 5 Nb 4 Ti 3 O 21 phase is −144.3 ppm/°C through the simulation and numerical value calculation. Furthermore, the LiNb 0.6 Ti (0.5−x) Ca 1.231x O 3 ceramic shows a higher dielectric constant e r and a denser microstructure. The LiNb 0.6 Ti (0.5−x) Ca 1.231x O 3 ceramic with x = 0.03 sintered at 1100 °C for 2 h shows excellent microwave dielectric properties: e r  = 76.89, Q × ƒ = 4064 GHz, τ ƒ  = 0.25 ppm/°C.