Publications (2)1.19 Total impact
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Article: Fabrication and properties of 2D EBGs by moulding/demoulding with high permittivity ceramics
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ABSTRACT: Two-dimensional electromagnetic bandgap structures (2D EBGs) are designed and fabricated by moulding/demoulding. A high permittivity and low dielectric loss microwave material, Bi2O3-ZnO-Nb2O5 (BZN) was used. The impacts of high permittivity on the 2D EBGs’ properties are investigated. As the experiments showed, wide electromagnetic band gap is found in the frequency ranges from 5.6 to 10.6GHz, and 12.6 to 16.6GHz. The first gap is greater than 60% of the gap center frequency, while the second gap is 25% of the center frequency. The interval between the two gaps is larger than 2GHz, and the return loss of both gaps is as large as −40dB. This interesting phenomenon of multi band gaps is very useful for diplexers, multi-mode tunable dielectric antennas and resonators. Based on these, expansive applications may be exploited in the future. The experimental results are in good agreement with the simulations’.Journal of Electroceramics 04/2012; 21(1):452-456. · 1.19 Impact Factor -
Article: Mn4+ and W6+ substitution on Bi2O3–ZnO–Nb2O5-based low firing ceramics
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ABSTRACT: The ion substitution with Mn4+ and W6+ co-substituted Nb5+ in B site of a low firing Bi2O3–ZnO–Nb2O5-based A2B2O7 pyrochlore ceramics was investigated. The Mn4+ and W6+ co-substitution was tentatively introduced in cubic-monoclinic pyrochlores co-existing ceramics Bi3xZn2−3x(ZnxNb2−x−2yMnyWy)O7 (x=0.5–0.65, y=0, 0.02, 0.05, 0.1) and the results shows interested regular influence on the structure, dielectric properties with the amount of substitution amount change. With the structure evaluation and electrical properties measurement results, the Mn4+ and W6+ substituted Nb5+ in B site shows effective to depress the grain growth and the ceramic with fine grains in 1–3 μm can be obtained. The electrical properties was also enhanced in smaller substitution amount but degraded with the substitution amount increasing. Based on these results, small amount of Mn4+ and W6+ substitution was successfully applied to a base ceramic with the electrical properties satisfied the NP0 specification to miniaturize the grains and enhance the sintering behavior.Ceramics International. 30(7):1219-1223.
