Research On The Regulation Of The Surface Traveling Wave Attenuation Characteristics Of The Absorbing Film

With the rapid development of radar technology,the radar detection system is becoming more and more perfect,and the threat of stealth weapons in the battlefield is also increasing.Stealth performance is not only an important basis for measuring the survivability of weapons,but also an important criterion for judging the advancement of them.Through the design of the shape and the use of radar absorbing materials,the specular scattering has been better suppressed.The dispersion of traveling wave in non-specular scattering accounts for a large increase in the proportion of total scattering,which has become the main problem of stealth weapons and equipments.In this paper,Calculating the attenuation constant of the surface traveling wave in the absorbing film by the simplified method,and then discussing the influence of electromagnetic parameters,filling ratio and thickness of absorbing film on the attenuation constant.Based on the analysis,the absorbing film with different parameters was prepared by casting and hot pressing process.The RCS of the absorbing film was tested and analyzed by the microwave darkroom.The details are as follows:(1)Through the classical dispersion equation and the simplified dispersion equation,the attenuation constants of the absorbing film on the traveling wave of the radar surface are calculated respectively,comparing and analyzing the difference between the two calculation methods.According to the simplified calculation equation,analyzing the influence of the thickness and the electromagnetic parameters on the attenuation constant by the idea of control variables.It was found that the complex permeability of the material has a decisive influence on the attenuation constant when compared to the complex permittivity.Through the theoretical analysis of the surface traveling wave attenuation characteristics,the correctness of the conclusion is verified,which provides a theoretical basis for the preparation of the absorbing film.(2)Based on the attenuation law,reduced iron powder,carbonyl iron powder and iron cobalt powder with good magnetic loss performance are selected as the absorbent.Making the powder from spherical to flake by mechanical ball milling,analyzing the morphology and the electromagnetic parameters of the micropowder,then calculating the attenuation constant.It is found that the attenuation property of the magnetic alloy micropowder after flaking is significantly improved,and the peak will move to the low frequency.As the ball milling time is prolonged,the flaky micropowder will be slowly broken,and the peak will start moving to the high frequency.(3)The treated magnetic metal powder was used as an absorbent and the nitrile rubber was used as a matrix,testing the RCS of the absorbing film which was prepared by casting and hot pressing.Changing the electromagnetic parameters of the absorbing materials,the thickness of the film and the filling ratio,studying the RCS changes of the absorbing film at 4 GHz,8 GHz and 12 GHz.Compared with the variation law of the attenuation constant obtained by theoretical calculation in Chapter 4,verifying the law.