Magnesium fluoride doped MgTiO3 ceramics with ultra-high Q value at microwave frequencies

Abstract

Microwave ceramic with ultra-high Q value is one of the most significant classes of material to realize the miniaturization and integration of microwave devices. In this paper, to improve the microwave dielectric properties of ceramics, MgTiO3-x wt.% MgF2 (x = 0, 3, 4, 5, and 6) microwave ceramics with high-quality factor were synthesized by solid-state reaction method. The effects of MgF2 addition on the phase composition, sintering behavior, and microwave dielectric properties of MgTiO3 were investigated. In comparison to pure MgTiO3, our study demonstrates that the Q × f values can be dramatically enhanced with the doping of MgF2. After being sintered at 1300 °C for 4 h, the MgTiO3-3 wt.% MgF2 showed the best microwave dielectric properties of εr ∼18.09, Q × f ∼262,900 GHz (at 8.98 GHz) and τf ∼ −41.5 ppm/°C. The outstanding performance of MgF2 doped MgTiO3 ceramics provides a solid foundation for widespread applications of microwave dielectric substrates, resonators, filters and patch antennas in modern wireless communication equipment.