Polaron conduction loss in microwave dielectric ceramics

It has been generally accepted that the product of the unloaded quality fac tor and resonant frequency is the universal parameter for comparison of die lectric resonators with different size. (1,2) 2 However, it is suggested in this study that this universal parameter should be modified due to the pre sence of the polarons. From the frequency dependence of the unloaded qualit y factor, it is possible to extract the factor determined only by the phono n scattering effects, and we denoted this parameter by Q(s),, It was found that the a, parameter for ZrxSnzTiyO4 (ZST) and Ba(Zn1/3Ta2/3)O-3 (BZT) cer amics showed constancy in the frequency range of 2-12 CHz, which supports t he idea of polaron conduction loss contribution to the dielectric loss.