Microwave dielectric properties of Al2O3-TiO2 improved by addition of ZnO

Microwave dielectric properties of rutile (TiO2) and ZnO added alumina (Al 2 O 3 ) ceramics have been studied for millimeter wave applications. Our objective was to achieve high quality factor (Q) and to improve temperature coefficient of resonant frequency (tau(f)) of Al2O3 ceramics. A relationship between the crystalline phase and microwave dielectric property was observed. Excellent microwave dielectric properties (Q center dot f = 187,000 GHz, epsilon(r) = 12.9) including near zero tau(f) (tau(f) = -2.9 ppm/degrees C) was obtained in 0.89Al(2)O(3) -0.11TiO(2) ceramics with 0.5 wt% of ZnO, when they were sintered at 1300 degrees C for 5 h.