Sintering Behavior and Dielectric Properties of ZnNb2O6–TiO2 Ceramic System at Microwave Frequency

High-dielectric-constant and low-loss ceramics in the (1-x)ZnNb2O6–xTiO2 two phase ceramic system have been prepared by the conventional mixed oxide route and their microwave dielectric properties have been investigated. Over-grown TiO2 grains were observed in the over-sintered specimens, which would lead to the inhomogeneous grain growth and a decrease in Q× f. The τf increases with increasing TiO2 content and tunes through zero at x=0.6. Specimen with x=0.6 possessed an excellent combination of microwave dielectric properties: εr∼46.2, Q× f∼48,000 GHz and τf∼-0.6 ppm/°C. The two phase ceramic is proposed as a very promising candidate material for small-sized global positioning system (GPS) patch antennas.