Effects of Ceramics on Dielectric Properties of Polystyrene / Ceramics Composites at Microwave Frequencies

Dependencies of dielectric properties on MgTa2O6, MgNb2O6, and MgWO4 (Mg-based ceramics) fillers of the polystyrene (PS) matrix composites were investigated as a function of frequency. With increasing frequency from 1 GHz to 7.3 GHz, the dielectric constant (K) of the composites was not changed significantly, while the dielectric loss (tan delta) of the composites was slightly decreased. The K, tan delta, and temperature coefficient of resonant frequency (TCF) of the composites were dependent on the type and amount of ceramics at 11 GHz. Also, several theoretical models have been employed to predict the effective dielectric constant of the composites and the results were compared with experimental data. Typically, a K value of 6.67, tan delta of 0.56 x 10(-3), and TCF of -4.99 ppm/degrees C were obtained for the PS composites with 0.4 volume fraction of MgNb2O6 at 11 GHz.