Temperature stable Sr₂MgSi₂O₇-Sr₃V₂O₈ microwave dielectric composite ceramics for LTCC applications

A comprehensive exploration is conducted on the phase constituents, crystal structures, dielectric properties, and thermal performances of the innovative (1-x)Sr₂MgSi₂O₇- x Sr₃V₂O₈ (0.4 ≤ x ≤ 0.5) composite ceramics. Experimental findings indicate that the 0.55SMS-0.45SV ceramic, which was sintered at 1150 °C for 4 h, exhibits excellent microwave dielectric properties (Q×f = 22,300 GHz at 10.79 GHz, ε_r = 11.0, τ_f = +1.7 ppm/°C). Notably, the 0.55SMS-0.45SV composite ceramic doped with 4 wt% Glass 9 (Si-B-Al-Ca-Ba-Mg-Li-Na-K, G9), which was sintered at 925 °C for 4 h, exhibits not only excellent microwave dielectric properties (Q×f = 13,100 GHz at 11.03 GHz, ε_r = 10.5, τ_f = +2.2 ppm/°C), but also favorable thermal performances, including a thermal conductivity of 2.31 W/(m·K) and a coefficient of thermal expansion (CTE) of + 10.6 ppm/°C. Additionally, the 0.55SMS-0.45SV + 4 wt%G9 ceramic demonstrates good compatibility with silver (Ag) electrodes, indicating substantial application potential in Low-Temperature Co-Fired ceramic (LTCC) technology.