The Radar Absorbing Properties Of The Polycrystalline Iron Fibers

In the paper, the production and electromagnetic wave absorbing properties of polycrytalline iron fibers (PIF) were studied mostly. First, the PIF were produced by inducing magnetic field metal organism chemical vapor decompose. A series test show that when the content of iron fibers is less than 65%wt the coating have good performance and the planar density of the coating is greatly reduced. When the content of iron fibers is 60%wt, theplanar density only is 1,85kg/m2 , the bandwidth is 4.2GHz that the reflectivity is less than -8dB, the least reflectivity is -16.5dB. We measure electromagnetic parameter of the PIF. The result show that the permeability and permittivity of PIF were both complex number. The real and imaginary part of the permeability and permittivity of the PIF were relatively larger. The relations between thickness ofthe coating and the reflectivity were discussed because the thicknessthe coating and the reflectivity were discussed because the thickness of the coating is also a key factor affected the reflectivity.The reason why more and more attention was give to the PIF in recent years is the anisotropy of the electromagnetic of the PIF. The axial permittivity of the PIF is much larger than the radial and the axial permeability is larger than the radial, so that the reflectivity of the coating is affected by the orientation of the PIF in the coating. In the paper, the anisotropy of the electromagnetic of the PIF and its effect to the reflectivity were verified by the test. The results of test show when the iron fibers were orientation the reflectivity varied with the different polarization and incidence of the incident electromagnetic wave.At the end of the paper, combining the engineering application of PIF to the design of radar absorbing coating, we produced a kind of radar absorbing painting, the painting satisfied the criteria of design. The comparison the stainless steel flake with the PIF in different way give more reference in roundly knowing the properties of PIF.