Bio-template synthesis of hollow Fe3O4 fibers and their enhanced microwave absorption performance in Ku-band

A novel kind of microwave absorption composite in Ku-band with low cost, low density and strong absorption was prepared through Bio-template carbonization and solvothermal method. The phase structures and morphologies of the composite had been characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The microwave absorption properties of carbonized kapok fibers and Fe3O4/kapok fibers were measured by vector network analysis (VNA). When the sample thickness is 1.5 mm, the Fe3O4/kapok fibers have an optimal absorption peak value of about -24.1 dB at 17.4 GHz and its effective absorption bandwidth lower than -10 dB reaches 2.4 GHz (from 15.6 to 18.0 GHz). The reflection loss results indicate that the Fe3O4/kapok fibers possess higher microwave absorption in the Ku-band. A possible mechanism of the improved microwave absorption performance of the composite was discussed.