High Electromagnetic Wave Absorption Performance of Silicon Carbide Nanowires in the Gigahertz Range

The electromagnetic (EM) wave absorption properties of 2-mm-thick silicon carbide nanowire (SiCNW)−epoxy composites were studied in the range of 2−40 GHz using a free-space antenna-based system. The 35 wt % SiCNW composites exhibited dual-frequency EM wave absorptions of −31.7 and −9.8 dB at 8.3 and 27 GHz, respectively. The minimum reflection loss of −32.4 dB was achieved at 31.1 GHz for the composites containing 25 wt % SiCNW. A study of the loss mechanism of EM wave absorption suggests the combination of the electric conductance loss caused by network-like SiCNWs in the resin matrix and the relaxation polarization loss in the interfaces of SiCNWs and the epoxy resin.