| Ceramics with high frequency, high dielectric constant and high reliability were studied in this paper. The type of glass doped in the BaO-Nd2O3-TiO2 system had great impact on the properties of the ceramic. The dielectric constant of the BaO·Nd2O3·5TiO2 system could not be improved by the glass prepared by Pb3O4, SiO2 and BaCO3, but the dielectric loss of it was much smaller. When the content of this glass was 0.5wt%, sintered at 1140℃, the dielectric properties were as follows:εr=99.9,tanδ=1.12×10-4,αc=-88.96×10-6/℃。The other type of glass which was mainly prepared by Pb3O4 and Bi2O3, at the same time some ZnO, H3BO3 and Al2O3 were added in the glass to improve the dielectric properties. When the BaO·Nd2O3·5TiO2 system doped with this kind of glass sintered at low temperature, its dielectric constant can be improved effectively, however, its dielectric loss was a little higher and temperature coefficient of the capacitance was rather negative.Adjusting the mole content of TiO2 in the system, it could be found that the temperature coefficient of the capacitance shifted to the positive with the increasing content of TiO2, but the sintering temperature was increased. When the mole percentage of BaO-Nd2O3-TiO2 system was 1:1:4.8, better properties could be gained at lower sintering temperature. The glass had no influence on the major phase, when added 8-9wt% of glass, the dielectric properties were excellent:ε≈100,αc<0±15×10-6/℃, tanδ<5×10-4.The impact of the glass on the breakdown properties of the system was also discussed in this paper. It was found that when the content of glass was 7-8wt%, the breakdown field strength was over 20kV/mm, but there was no obvious relationship between the breakdown property and insulated volume resistivity.
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