Low-loss microwave dielectrics in the (Mg_1-xZn_x) ₂TiO₄ ceramics

The microwave dielectric properties and the microstructures of (Mg _1-xZn_x)₂TiO₄ ceramics prepared by the conventional solid-state route were investigated. Lattice parameters were also measured for samples with different x. As x increased from 0 to 0.05, the Q × f of the specimen can be promoted from 150 000 GHz to a maximum 275 300 GHz. It also showed a remarkable lowering in the sintering temperature (∼100°C). Ilmenite-structured (Mg_0.95Zn_0.05) TiO₃ was detected as a second phase. The coexistence of the second phase, however, is not harmful to the dielectric properties of the specimen because it possesses compatible ones. A fine combination of microwave dielectric properties (ε_r∼15.48, Q × f∼275 300 GHz, τ_f∼-34 ppm/°C) was obtained for (Mg_0.95Zn _0.05)₂TiO₄ specimen sintered at 1330°C for 4 h. It is proposed as a very promising dielectric material for low-loss microwave and millimeter wave applications.