Effect of SnO₂ substitution on microwave dielectric characteristics of Zn_0.15Nb_0.3Ti_0.55O₂ ceramics

Abstract The relevance of Sn⁴⁺ substituted for Ti⁴⁺ of Zn_0.15Nb_0.3Ti_0.55O2 ceramics is investigated. X-ray diffraction patterns indicate that the major phase can be matched with Zn_0.15Nb_0.3Ti_0.55O2 and a second phase ZnTiNb₂O₈ appears in different composition. The content of ZnTiNb₂O₈ phase gradually increases along with more substitution, which is contributed to the decline of ϵ_r. The decrease of grain size and the observed pores have negative influence on Q × f values. And the τ_f values move towards a lower value, corresponding to the variation of ϵ_r. An optimal combination of microwave dielectric properties is: ϵ_r = 83.2, Q × f = 15456 GHz, τ _f = 301.5 ppmfC with x = 0.03, sintered at 1050 "C. (paper)