Microwave dielectric properties of MgTiO3–SrTiO3 layered ceramics

MgTiO3–SrTiO3 layered ceramics with different stacking were fabricated and the microwave dielectric properties were evaluated with TE011 mode. With increasing SrTiO3 thickness fraction, the resonant frequency (f0) decreased, while the effective dielectric constant (ɛr,eff) and temperature coefficient of resonant frequency (τf) increased for the bi-layer ceramics. The stacking arrangement also had significant effect on the microwave dielectric properties. For the same SrTiO3 thickness fraction of 0.333, the tri-layer MgTiO3/SrTiO3/MgTiO3 ceramics had lower f0, higher ɛr,eff and τf. The result was not consistent with the previous report on the layered ceramics with TE011 mode [Cho, J. Y., Yoon, K. H. and Kim, E. S., Effect of stress on microwave dielectric properties of layered Mg0.93Ca0.07TiO3–(Ca0.3Li0.14Sm0.42)TiO3 ceramics. Mater. Chem. Phys. 2003, 79, 286; Cho, J. Y., Yoon, K. H. and Kim, E. S., Correlation between arrangement of dielectric layers and microwave dielectric properties of Mg0.93Ca0.07TiO3–(Ca0.3Li0.14Sm0.42)TiO3 ceramics. J. Am. Ceram. Soc. 2003, 86, 1330], where the effective dielectric constant was only determined by the thickness fraction and was independent of the stacking arrangement. Finite element analysis gave an explanation for the different microwave dielectric behaviors of the bi- and tri-layer ceramics in the present experiment.