Enhanced Quality Factor of Zinc Lanthanum Borates-Based Dielectrics via the Control of ZnO/B2O3 Ratio
A dielectric system having an exceptionally high-quality factor of 1350 at 16.8 GHz is reported as a strong candidate for glass-based low-temperature cofireable materials. The dielectrics are based on unusual (16–27)ZnO·16La2O3·(57–68)B2O3 glass mixed with a fixed 50 wt% Al2O3 filler. The ratio of ZnO/B2O3 was found to be critical in controlling the nature of glass and, consequently, performance of the dielectric mixture. For example, 27ZnO·16La2O3·57B2O3 glass sample having the highest Zn content resulted in the lowest softening temperature of 647°C and the least porosity of ∼6%. The enhanced densification and extensive crystallization of low loss phases, i.e., LaAl2.03(B4O10)O0.54 and ZnAl2O4, are assumed to be responsible for better dielectric performance that resulted from the increase of Zn content in glass.
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Document Type: Research Article
Affiliations: Department of Materials Science and Engineering, Yonsei University, Seoul 120-749, Korea
Publication date: 2010-02-01