Ku-band electromagnetic wave absorbing properties of polysiloxane derived Si-O-C bulk ceramics

The bulk Si-O-C ceramics were prepared by polymer derived ceramics (PDCs) route using polysiloxane as precursor and their properties were investigated for electromagnetic wave absorbing in the frequency range of 12.4–18 GHz (Ku-band). It was found that the catalytic pyrolysis can enhance substantially the absorbing properties by in situ formation of turbostratic carbon network, ordered carbon, and multi-wall carbon nanotubes. The matching thickness of sample containing 1.5 wt% FeCl₃ (FPSO-1.5) is 2.2 mm, and its reflection loss exceeds −10 dB in the whole Ku-band with an absorption peak of −35.48 dB at 14.16 GHz. For sample containing 1.5 wt% FeCl₃, its absorption peak increases to −15.78 dB, but its matching thickness decreases significantly to 2.2 mm. The polymer derived Si-O-C ceramics could be used as excellent electromagnetic functional devices working in harsh environments. (paper)