New dielectric material system of La(Mg1/2Ti1/2)O3-Ca0.6La0.8/3TiO3 for microwave applications

The microstructure and microwave dielectric properties of xLa(Mg1/2Ti1/2)O-3-(1-x)Ca0.6La0.8/3TiO3 ceramics system with ZnO additions (0.5 wt.%) investigated by the conventional solid-state route have been studied. Doping with ZnO (0.5 wt.%) can effectively promote the densification and the dielectric properties of xLa(Mg1/2Ti1/2)O-3-(1 - x)Ca0.6La0.8/3TiO3 ceramics. 0.6La(Mg1/2Ti1/2)O-3-0.4Ca(0.6)La(0.8/3)TiO(3) ceramics with 0.5 wt.% ZnO addition possess a dielectric constant (epsilon(r)) of 43.6, a Q x f value of 48,000 (at 8 GHz) and a temperature coefficient of resonant frequency (tau(f)) of - 1 ppm/degrees C sintering at 1475 degrees C. As the content of La(Mg1/2Ti1/2)O-3 increases, the highest Q x f value of 62,900 (GHz) for x = 0.8 is achieved at the sintering temperature 1475 degrees C. A parallel-coupled line band-pass filter is designed and simulated using the proposed dielectric to study its performance. (C) 2009 Elsevier B.V. All rights reserved.