In the present study, dielectric and microwave absorbing properties of barium titanate (BaTiO3) and strontium ferrite (SrFe12O19) filled thermoplastic polyurethane composites were investigated. The variations of the dielectric parameters of the BaTiO3 filled composite samples with filler concentration were also modeled and simulated by the power-law model to predict dielectric coefficients of the samples for higher filler concentrations. Comparing the prediction of the Power-law model and experimental measured dielectric values indicate that the Power-law model predicts dielectric parameters of the composite with acceptable accuracy. Microwave absorption analyses of the composite samples showed that SrFe12O19 is more effective than BaTiO3 on the enhancement of microwave absorption capability of TPU. The hybrid composite samples that contained both SrFe12O19 and BaTiO3 were also prepared, and their microwave absorption performance was evaluated. It was observed that much lower RL values than that of the composite samples, which were filled SrFe12O19 or BaTiO3 could be obtained by the hybrid composites. However, absorption bandwidth of them was narrower than counterparts that contained the same amount of SrFe12O19.
