Crystal structure, mixture behavior, and microwave dielectric properties of novel temperature stable (1 − x)MgMoO4 − xTiO2 composite ceramics

Novel temperature stable MgMoO4-TiO2 microwave dielectric ceramics were prepared by a solid state reaction process at low temperature (950 °C). As TiO2 content increases, the relative permittivity increases while the Q × f value decreases, and the variation mechanisms are proposed, respectively. The temperature coefficient of resonant frequency (τf) shifts to the positive direction as TiO2 is added. The mixture mechanisms of τf value for two-phase composite materials are supposed. A near-zero τf value (3.2 ppm/°C) is obtained when x = 0.3, with εr = 9.13 ± 0.03 and Q × f = 11,990 GHz. The 0.7MgMoO4-0.3TiO2 composites are considered to be appropriate as a low temperature co-fired ceramic material for microwave wireless communication applications.