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:
Aug. 23, 1994
Filed:
Aug. 02, 1993
Tokiomi Katoh, Nagoya, JP;
Hirofumi Ozeki, Nagoya, JP;
NGK Spark Plug Company, Ltd., Aichi, JP;
Abstract
Disclosed herein is a microwave dielectric ceramic composition which comprises as the main ingredient, a composition represented by xMgTiO.sub.3 .multidot.(1-x)CaTiO.sub.3 (0.93.ltoreq.x .ltoreq.0.95), to which 3-9 wt % of ZnO, 2-4 wt % of Ta.sub.2 O.sub.5, 1-6 wt % of Nb.sub.2 O.sub.5, 0.1-6 wt % of MnO.sub.2, 3-12 wt % of Al.sub.2 O.sub.3 or 3-12 wt % of Co.sub.2 O.sub.3 to xMgTiO.sub.3 .multidot.(1-x)CaTiO.sub.3. 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/.degree.C. and relative dielectric constant (.epsilon..sub.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..sub.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.