Microwave dielectric properties of Mg4Nb2O9-3.0wt.% LiF ceramics prepared with CaTiO3 additions

• Published in: Journal of the European Ceramic Society 2005, Vol.25 (12), p.2871-2875
• Main Authors: YOKOI, Atsushi, OGAWA, Hirotaka, KAN, Akinori, OHSATO, Hitoshi, HIGASHIDA, Yutaka
• Format: Article
• Language: English
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric loss and relaxation; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Electrotechnical and electronic ceramics; Exact sciences and technology; Permittivity (dielectric function); Physics; Technical ceramics
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2005.03.157

A family of low--temperature co--fired ceramics (LTCC) based on mixtures of Mg4Nb2O9--3*0wt.% LiF (MNLF) and CaTiO3 ceramics has been investigated for microwave applications. In this study, it was found that, when increasing amounts of CaTiO3 additions from 0 to 10wt.%, the temperature coefficient of resonant frequency (tauf) extremely varied from --71*5 to 39*9ppm/ deg C. The dielectric constants (*?r) increased from 12*3 to 18*3 and the quality factor (Q.f) drastically decreased from 118,989 to 11,119GHz. From these results, the MNLF--6wt.% CaTiO3 ceramic sintered at 950 deg C for 10h was shown to be the appropriate dielectric properties: *?r=15*7, Q.f=22,098GHz, and tauf=--3*3ppm/ deg C. As for the chemical compatibility of MNLF--6wt.% CaTiO3 ceramic with Ag, any secondary phase was not recognized from the XRPD profile of the samples heat--treated at 920 deg C for 10h. Thus, it was considered that the MNLF--xwt.% CaTiO3 ceramics are applicable to the multilayer devices with silver.