Study on shielding functionally gradient materials with low reflection loss and high absorption loss for electromagnetic wave

In this paper, the double gradient model for shielding functionally gradient materials (SFGMs) with low reflection loss and high absorption loss in less than 1 GHz is put forward to reduce pollution of the electromagnetic wave. In SFGMs, double impedance matching layers on the surface and high absorption layer in center and double impedance transition layers between the surface and center are designed. The based on nickel and (Ni,Zn)Fe/sub 2/O/sub 4/ gradient composite shielding coatings are prepared. The test results of the coatings showed that, the reflection loss was decreased 6/spl sim/8 dB and the absorption loss was increased 6/spl sim/14 dB.