Sintering behavior and dielectric properties of ZnNb₂O _6-TiO₂ ceramic system at microwave frequency

High-dielectric-constant and low-loss ceramics in the (1 - x)ZnNb ₂O₆-xTi_O2 two phase ceramic system have been prepared by the conventional mixed oxide route and their microwave dielectric properties have been investigated. Over-grown TiO₂grains were observed in the over-sintered specimens, which would lead to the inhomogeneous grain growth and a decrease in Q×f. The τtf 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: ετ 46:2, Q×f ∼ 48;000GHz and τt ∼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.