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Abstract

The dielectric ceramic composition of the first aspect of the invention comprises an essential component having a compositional formula of xBaO-yTiO.sub.2 -zNd.sub.2 O.sub.3 (wherein 0.02.ltoreq.x.ltoreq.0.2, 0.6.ltoreq.y.ltoreq.0.8, 0.01.ltoreq.z.ltoreq.0.3, x+y+z=1), and contains two types of glass powder, one comprising PbO, ZnO and B.sub.2 O.sub.3 and the other comprising SiO.sub.2 and B.sub.2 O.sub.3, and a third component that comprises Al.sub.2 O.sub.3, SrTiO.sub.3, GeO.sub.2 and Li.sub.2 O. Its advantages are that it can be sintered at low temperatures, its dielectric constant .epsilon..sub.r falls between 10 and 50 or so, its unloaded Q is large, and its temperature-dependent resonant frequency change is small. The dielectric ceramic composition of the second aspect of the invention comprises an essential component having a compositional formula of s(xBaO-yTiO.sub.2 -zNd.sub.2 O.sub.3)-tNd.sub.2 Ti.sub.2 O.sub.7 (wherein 0.02.ltoreq.x.ltoreq.0.2, 0.6.ltoreq.y.ltoreq.0.8, 0.01.ltoreq.z.ltoreq.0.3, x+y+z=1, 0.1.ltoreq.s.ltoreq.0.8, 0.2.ltoreq.t.ltoreq.0.9, s+t=1), and contains two types of glass powder, one comprising PbO, ZnO and B.sub.2 O.sub.3 and the other comprising SiO.sub.2 and B.sub.2 O.sub.3, and a third component that comprises Al.sub.2 O.sub.3, SrTiO.sub.3, GeO.sub.2 and Li.sub.2 O. Its advantages are that it can be sintered at low temperatures, its dielectric constant .epsilon..sub.r falls between 10 and 50 or so, its unloaded Q is large, and its absolute value of a temperature coefficient of resonant frequency .tau..sub.f is small. Still another advantage of the composition is that its relative dielectric constant .epsilon..sub.r, its unloaded Q and its temperature coefficient of resonant frequency (.tau..sub.f) can be controlled in any desired manner by controlling the Nd.sub.2 Ti.sub.2 O.sub.7 content of the composition.

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First Claim