Temperature compensating microwave dielectric based on the (Mg 0.95Ni 0.05)TiO 3-(La 0.5Na 0.5)TiO 3 ceramic system

Abstract

The microstructures and microwave dielectric properties of the novel temperature-compensated composite ceramic (1-x)(Mg 0.95Ni 0.05)TiO 3-x(La 0.5Na 0.5)TiO 3 were investigated. Dense and mixed phase samples were produced in the range of 0.05≤x≤0.9. When the x value increased, the quality factor (Q × f) decreased nonlinearly while the dielectric constant (ε r) steadily increased almost linearly due to the compensation effect. The temperature coefficient of resonant frequency (τ f) was remarkably improved with an increase of (La 0.5Na 0.5)TiO 3 content. With x=0.13, a dielectric constant (ε r) of 23.22, a Q × f value of 86,500 GHz, and a τ f value of 2.8 ppm/°C was obtained for 0.87(Mg 0.95Ni 0.05)TiO 3-0.13(La 0.5Na 0.5)TiO 3 ceramics sintered at 1275°C for 4 h. Moreover, a band-pass filter with traditional hairpin resonators with a center frequency of 2.4 GHz was designed and fabricated using the proposed dielectric ceramic to study its performance. © 2009 The American Ceramic Society.