Enhanced absorption property of ordered mesoporous carbon/Co-doped ordered mesoporous carbon double-layer absorber

Ordered mesoporous carbon (OMC) and metal-doped (M-doped) OMC composites are prepared and their electromagnetic (EM) parameters are measured. Using the measured EM parameters we calculate the EM wave absorption properties of double-layer absorber which is composed of OMC as an absorbing layer and M-doped OMC for matching layer. The calculated results show that the EM wave absorption performance of OMC/OMC-Co (2.2 mm/2.1 mm) is improved remarkably. The obtained effective absorption bandwidth is up to 10.3 GHz and the minimum reflection loss reaches -47.6 dB at 14.3 GHz. The enhanced absorption property of OMC/OMC-Co can be attributed to the impedance match between air and absorber. Moreover, it can be found that for the absorber with given matching layer, larger value of Δ tanδ_ε (=tan δ_{ε absorbing} -tan δ_{ε matching}) can induce better absorption performance, indicating the impedance difference between absorbing layer and matching layer plays an important role in improving the absorption property of double-layer absorber.