High-Q×f 0.95 MgTiO3–0.05CaTiO3 microwave dielectric ceramics with the addition of LiF sintered at medium temperatures

High-Q×f 0.95MgTiO3–0.05CaTiO3 (MT–CT) glass-free microwave dielectric ceramics with LiF (1–4 wt%) were fabricated by a conventional solid-state reaction method at medium temperatures. The effects of LiF additive on the phase compositions, microstructures, and microwave dielectric properties of the MT–CT ceramics were studied. The results showed that LiF effectively enhanced the densification and lowered the sintering temperature of the MT–CT ceramics without deteriorating the quality factor (Q×f) values significantly. The optimal microwave dielectric properties of εr = 17.96, Q×f = 70572.4 GHz, and τf = –18.77 ppm/°C were achieved in the MT–CT ceramics with 2 wt% LiF sintered at 1150 °C, which is approximately 250 °C lower than the sintering temperature of conventional MT–CT ceramics.