Ngk Spark Plug Company, Limited

Toshihiro Mizui

Kazuhisa Itakura

Takuya Tarutani

The present invention relates to a microwave dielectric ceramic composition exhibiting excellent dielectric characteristics, including high Qu; and to a dielectric resonator which exhibits high Qu even when of large size. The present invention provides a microwave dielectric ceramic composition containing a primary component represented by CaTiO-(1-x)REAlO[0.54&#x2266;x&#x2266;0.82] (wherein RE is composed only of an essential element La or composed of an essential element La and one or two optional elements selected from among Nd and Sm). The present invention also provides a microwave dielectric ceramic composition containing a primary component represented by the compositional formula: xCaTiO-(1-x)LnAlO[0.54&#x2266;x&#x2266;0.82] (wherein Ln is at least one species selected from among Y, La, Nd, Sm, etc.); and Na in an amount as reduced to NaO of 0.02 to 0.5 parts by mass on the basis of 100 parts by mass of the primary component. The present invention also provides a dielectric resonator produced from the aforementioned microwave dielectric ceramic composition.

Microwave dielectric porcelain composition and dielectric resonator

The present invention provides a microwave dielectric porcelain composition having excellent properties, i.e., practically sufficient relative dielectric constant and unloaded Q value and a very small absolute temperature coefficient of resonant frequency. A novel microwave dielectric porcelain composition is provided, comprising a main component having a perovskite type crystalline structure represented by the general formula (Ca.sub.x, Sr.sub.y, Nd.sub.z).sub.1+a TiO.sub.3+b [in which x, y and z each represent a molar ratio and satisfy the following relationships: x+y+z=1, 0.430.ltoreq..times..ltoreq.0.650, 0.260.ltoreq.y.ltoreq.0.440, 0.090.ltoreq.z.ltoreq.0.130; a satisfies the relationship: 0.010.ltoreq.a.ltoreq.0.300; and b satisfies the relationship: 0.100.ltoreq.b.ltoreq.1.000], Al.sub.2 O.sub.3, and at least one of oxides of elements of Ca, Sr, Nd, Ti and Al, wherein the content of Al.sub.2 O.sub.3 and said oxides are from 10 to 12% by weight and from 1 to 2% by weight, respectively, based on 100% by weight of said main component. The oxides are preferably Nb.sub.2 O.sub.5 and MnO.sub.2.

Microwave dielectric porcelain composition

The present invention provides a microwave dielectric porcelain composition having excellent properties, i.e., practically sufficient relative dielectric constant and unloaded Q value and a very small absolute temperature coefficient of resonant frequency. A novel microwave dielectric porcelain composition is provided, comprising a main component represented by the general formula (Ca.sub.x, Sr.sub.y, Nd.sub.z).sub.1+a TiO.sub.3+b �in which x, y and z each represent a molar ratio, with the proviso that x, y and z satisfy the following relationships: x+y+z=1, 0.780.ltoreq.x .ltoreq.0.900, 0.010.ltoreq.y.ltoreq.0.120, 0.090.ltoreq.z.ltoreq.0.130; a represents a number of from not less than 0.010 to not more than 0.300; and b represents a number of from not less than 0.100 to not more than 1.000!, A1.sub.2 O.sub.3, and at least one of oxides of elements other than Ca, Sr, Nd, Ti and Al, wherein the contents of Al.sub.2 O.sub.3 and said at least one of oxides of elements other than Ca, Sr, Nd, Ti and Al are from 10 to 12% by weight and from 1 to 2%, respectively, based on 100% by weight of the main component. The oxides are preferably Nb.sub.2 O.sub.3 and MnO.sub.2.

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Ise, Japan

Toshihiro Mizui