A low-sintering temperature microwave dielectric ceramic for 5G LTCC applications with ultralow loss

In next-generation mobile and wireless communication systems, low sintering temperature and excellent dielectric properties are synergistic objectives in the application of dielectric resonators/filters. In this work, Li2Ti0.98Mg0.02O2.96F0.04-1 wt% Nb2O5 (LTMN) ceramics were fabricated, and their sintering temperature was successfully lowered from 1120 degrees C to 750 degrees C by adjusting the mass ratio of B2O3-CuO (BC) additive. The optimum dielectric properties (epsilon(r) similar to 24.44, Q x f similar to 60,574 GHz and tau(f) similar to 22.8 ppm/degrees C) were obtained in BC-modified LTMN ceramics sintered at 790 degrees C. Even if their sintering temperature was lowered to 750 degrees C, the lowest temperature among the Li2TiO3 -based dielectric ceramics currently used for LTCC technology, excellent dielectric properties (epsilon(r) similar to 23.77, Q x f similar to 51,636 GHz) were still maintained. Additionally, no extra impurity phase was detected in BC-modified LTMN ceramics co-fired with Ag at 790 degrees C, indicating that BC-modified LTMN ceramics have a bright prospect in high-performance LTCC devices for 5G applications.