LBBS glass-modified Li2Mg2.975Co0.025TiO6 microwave dielectric ceramics with near-zero temperature coefficient for LTCC applications

A low-temperature co-fired ceramic (LTCC) material based on Co-doped Li 2 Mg 3 TiO 6 (Li 2 Mg 2.975 Co 0.025 TiO 6 ) with excellent microwave dielectric properties has been developed in this study. The effects of Li 2 O-B 2 O 3 -Bi 2 O 3 -SiO 2 (LBBS) glass addition on the phase composition, microstructure, and dielectric properties of Li 2 Mg 2.975 Co 0.025 TiO 6 ceramics sintered at 900 °C were systematically investigated. Furthermore, CaTiO 3 was incorporated to tune the temperature coefficient of resonant frequency (τ f ) to near-zero. The results indicate that the Li 2 Mg 2.975 Co 0.025 TiO 6  + 7 wt.% LBBS ceramic sintered at 900°C exhibits optimal comprehensive performance with a dielectric constant ( ε r ) of 11.65, a quality factor ( Q  ×  f ) of 53,599 GHz, and a τ f of − 30.1 ppm/ o C. After optimization with 8 wt.% CaTiO 3 addition, the final ceramic composition (Li 2 Mg 2.975 Co 0.025 TiO 6  + 7 wt.% LBBS + 8 wt.% CaTiO 3 ) achieves excellent dielectric properties: ε r  = 12.41, Q  ×  f  = 41,335 GHz, and τ f  =  − 0.92 ppm/ o C. Chemical compatibility tests confirm that this ceramic material demonstrates outstanding compatibility with Ag electrodes, exhibiting no chemical reactions or element diffusion after co-firing. The developed ceramic material satisfies the processing temperature requirements for LTCC technology and possesses promising potential for application in microwave passive components.