Impedance matching for omnidirectional and polarization insensitive broadband absorber based on carbonyl iron powders

Impedance matching is primary for broadband and strong absorption. Here, we optimized the impedance matching condition of the carbonyl iron powders (CIPs) layer by stacking the layered ultra high molecular weight polyethylene (UHMWPE). The double-layer absorber with its absorption more than 90% within the frequency range of 4.4–18 GHz is obtained by simulation and validated by experiment, while the single CIPs layer shows its broadest bandwidth only within 4.8–8.4 GHz. By simulating the angular performance, the double-layer has been confirmed to be omnidirectional and polarization insensitive. Besides, the impedance matching property of the double-layer is highly correlated with the thickness of UHMWPE layer, and the broadband absorption is resulted from the combination of the impedance matching layer and the absorbing layer. The designed absorber, stacked with the impact resistant UHMWPE layer, has great prospects for practical application under the requirement for bulletproof property.