Novel Temperature Stable Li_2MnO_3 Dielectric Ceramics with High Q for LTCC Applications

摘要

Novel microwave dielectric ceramics in the Li_2MnO_3 system with high Q prepared through a conventional solid-state route had been investigated. All the specimens exhibited single phase ceramics sintered in the temperature range 1140℃-1230℃. The microwave dielectric properties of Li_2MnO_3 ceramics were strongly correlated with sintering temperature and density. The best microwave dielectric properties of ε_r = 13.6, Q×f=97 000 (GHz), and τ_f= -5.2 ppm/℃ could be obtained as sintered at 1200℃ for 4 h. BaCu(B_2O_5) (BCB) could effectively lower the sintering temperature from 1200℃ to 930℃ and slightly induced degradation of the microwave dielectric properties. The Li_2MnO_3 ceramics doped with 2 wt % BaCu(B_2O_5) had excellent dielectric properties of ε_r = 11.9, Q׃= 80 600 (GHz), and τ_ƒ= 0 ppm/℃. With low sintering temperature and good dielectric properties, the BCB added Li_2MnO_3 ceramics are suitable candidates for LTCC applications in wireless communication system.