Journal of Materials Science, Vol.47, No.5, 2271-2277, 2012
Low loss and middle permittivity of (1-x) Ca4La2Ti5O17-xNdAlO(3) dielectric resonators with near-zero temperature coefficient of the resonant frequency
The crystal structures, microstructure and microwave dielectric properties of (1 - x) Ca4La2Ti5O17-xNdAlO(3) (0 a parts per thousand currency sign x a parts per thousand currency sign 0.7) ceramic system have been investigated. The results show that all the compositions form single-phase ceramics. The microwave dielectric properties are strongly correlated with composition, sintering temperature, grain sizes and lattice defects. The cell volume decreases because of the substitution of Al3+ for Ti4+ and Nd3+ for La3+ which is associated with a decrease in the permittivity. With increase in x value, the permittivity (epsilon (r) ), temperature coefficient of resonant frequency (tau (f) ) and Q x f value decrease. A near-zero tau (f) is achieved at x = 0.6 with permittivity of 41.8 and Q x f value of 13,783 GHz.