Electromagnetic and microwave absorbing properties of iron fibre-epoxy resin composites

In this paper, magnetic iron fibres of diameter down to 2 mum were produced by using the bundle-drawing method, and iron fibre-epoxy resin composites were prepared by mixing epoxy resin with the iron fibres. The electromagnetic parameters of the iron fibre-epoxy resin composites were measured using the transmission/reflection coaxial line method at microwave frequencies. The measured results show that the iron fibre-epoxy resin composites exhibit larger values of mu' and mu" in the frequency range of 2-18 GHz, and the values of both epsilon' and epsilon" steeply increase with increase in the fibre concentration. Based on a theoretical calculation of the reflection coefficient, the microwave absorbing properties of the iron fibre-epoxy resin composites were examined. The calculated results indicate that the iron fibre-epoxy resin composites exhibit good absorption performance in the radar band. The optimum absorption can be achieved by optimizing the fibre concentration. The absorption peak frequency can be manipulated easily by changing the thickness of the material layer. The calculated results also indicate that magnetic iron fibres may be useful in producing thin and lightweight radar absorbing materials.