The Research On Coating Method Of Two Dimension Low Scatter Metal Pylon

With electromagnetic stealth technology widely used on military aircraft,electromagnetic scattering properties of radar target are growing more important. Themeasurement of Radar Cross Section (RCS) is an important way in research ofelectromagnetic scattering properties. RCS testing techniques can verify the theoreticalresults and make up its deficiencies. RCS target support structures are an importantpart of RCS test site, it supports the target while increasing the background noise. Lowscattering metal pylon is a kind of support structure, which has a strong load capacity.For the purpose of reducing the background noise, the backward RCS can be reducedfurther by coating absorber.This paper studies the coating method of metal pylon. Three-dimensional pylonstructure is simplified to two-dimensional pylon structure for the high computingefficiency, and the coating method is analysed. The method of moments (MOM) basingon electromagnetic field integral equation was used, and MOM is more accurate thanother numerical methods. The metal-dielectric structure scatter model is establishedand the model is discretized and solved by MOM, the computing program is coded byFortran language.The absorption mechanism of absorber and its influence on backward RCS aredetermined by the following factors: the coating location (lighting area, shaded area),the polarization of the incident electromagnetic wave (vertical polarization, horizontalpolarization) and the parameters of coating layer (permittivity, magnetic permeabilityand electrical thickness). The influence of the above parameters on RCS is analyzed,the performance of a absorbing material used in engineering is analyzed. The analysisresult: when incident wave is VV polarization and coating in lighting area, thethickness of absorbing layer and the wavelength of incident wave must meet certainratio that the absorber will has a best performance. If absorbing materials meet thegeneral matching law, the absorbing rate could be tuned by adjusting general matchingconstant, and this adjusting does not affect the electrical thickness of absorber. Theparameters of the coating layer are optimized to obtain a better absorbing performance by the law got in research.This work has a great significance in manufacture of absorbing materials andtheoretical guidance for low scattering metal pylon coating method.