The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 02, 1999
Filed:
May. 14, 1998
Toshihiro Mizui, Ise, JP;
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
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.