| 摘要 |
Disclosed herein is a microwave dielectric ceramic composition which comprises as the main ingredient, a composition represented by xMgTiO3x(1-x)CaTiO3 (0.93</=x </=0.95), to which 3-9 wt % of ZnO, 2-4 wt % of Ta2O5, 1-6 wt % of Nb2O5, 0.1-6 wt % of MnO2, 3-12 wt % of Al2O3 or 3-12 wt % of Co2O3 to xMgTiO3x(1-x)CaTiO3. And the microwave dielectric ceramic compositions have a Qu value in the range of 3000 to 4600 (at 6 GHz), a temperature coefficient of the resonance frequency ( tau f) in the range of -10 to +10 ppm/ DEG C. and relative dielectric constant ( epsilon r) in the range of 18 to 22. The dielectric ceramic compositions are capable of reducing tau f approximately to zero or optionally and stably controlling tau f to a desired value both to positive and negative sides around zero as the center while maintaining epsilon r and Qu within practical characteristic ranges by controlling the addition (constitution) ratio of the specified oxides. Further, even if the sintering temperature is changed within a wide range, the sintering products of high density and high quality can be attained due to the addition of the specified oxides.
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