Low‐Temperature Sintering and Microwave Dielectric Properties of ( Mg 0.95 Zn 0.05 ) 2 ( Ti 0.8 Sn 0.2 ) O 4 –( Ca 0.8 Sr 0.2 ) TiO 3 Composite Ceramics

0.9( Mg 0.95 Zn 0.05 ) 2 ( Ti 0.8 Sn 0.2 ) O 4 –0.1( Ca 0.8 Sr 0.2 ) TiO 3 ( MZTS – CST ) ceramics were prepared by a conventional solid‐state route. The MZTS – CST ceramics sintered at 1325°C exhibited ε r  = 18.2, Q  ×  f  = 49 120 GHz (at 8.1 GHz), and τ f = 15 ppm/°C. The effects of LiF – Fe 2 O 3 – V 2 O 5 ( LFV ) addition on the sinterability, phase composition, microstructure, and microwave dielectric properties of MZTS – CST were investigated. Eutectic liquid phases 0.12 CaF 2 /0.28 MgF 2 /0.6 LiF and MgV 2 O 6 were developed, which lowered the sintering temperature of MZTS – CST ceramics from 1325°C to 950°C. X ‐ray powder diffraction ( XRPD ) and energy dispersive spectroscopy ( EDS ) analysis revealed that MZTS and CST coexisted in the sintered ceramics. Secondary phase Ca 5 Mg 4 ( VO 4 ) 6 as well as residual liquid phase affected the microwave dielectric properties of MZTS – CST composite ceramics. Typically, the MZTS – CST –5.3 LFV composite ceramics sintered at 950°C showed excellent microwave dielectric properties: ε r  = 16.3, Q  ×  f  = 30 790 GHz (at 8.3 GHz), and τ f  = −10 ppm/°C.