Improved Microwave Absorption of Carbonyl Iron Powder by the Array of Subwavelength Metallic Cut Wires

We present a scheme to improve the absorption performance of microwave absorbing materials by using the electric resonance resulting from an array of subwavelength metallic cut wires. To demonstrate this scheme, we have prepared a combined absorber (CA) by sandwiching the array of subwavelength copper cut wires between two layers of carbonyl iron powder (CIP) coating. Experimental results show that the prepared absorber has an evidently enhanced reflection loss (RL) and a significantly wider absorption bandwidth (4.5-9.5 GHz) for RL less than -10 dB compared to the CIP coating that has an absorption frequency range of 5-7 GHz. Numerical simulations confirm the experimental results, and further demonstrate that the absorption performance of the CA can be enhanced and tuned simply by adjusting the dimension of the cut wires, and the arrangement and layer number of the cut wire array (CWA), providing that the electric loss of the CWA is properly matched to the magnetic loss of CIP.