A new microwave dielectric ceramic for LTCC applications

A new low-sintering temperature microwave dielectric ceramic, the Li2TiO3 solid solution, was found and investigated in the Li2O-Nb2O5-TiO2 system. The compound with the composition of Li2.081Ti0.676Nb0.243O3 crystallizes as a monoclinic structure. This new microwave dielectric ceramic shows a relatively low permittivity (similar to 20), high Qxf values up to 50 000 (7.8 GHz), and near-zero temperature coefficients (13 ppm/degrees C), which were obtained via sintering at 1100 degrees C. The addition of <= 2 wt% B2O3 was very effective in lowering the sintering temperature (T-s), and dense ceramics could be obtained at T-s <= 900 degrees C. The addition of B2O3 does not induce apparent degradation in the microwave properties but lowers the tau(f) value to near zero. It is obvious that the ceramics could be promising candidates for multilayer low-temperature co-fired ceramics applications.