Design,Preparation And The Stealth Performance Of The Coding Structural Microwave Absorber

With the rapid development of science and technology,the problems of electromagnetic environmental pollution and electromagnetic interference engaged more attention.The development of intelligent military put forward higher requirements for the emerging electromagnetic stealth technology.As the key technology,microwave absorber not only has its special strategic position in military field,but also is widely used in civil field.Most of the traditional absorbing coatings have the problems of narrow absorbing bandwidth and larger surface density.The emergence of traditional metamaterials has set a new direction for absorbing materials.However,its high cost and complex preparation process limit its application in engineering to some extent.Therefore,how to design and prepare a new and practical wideband absorber with high performance has important engineering significance.In this paper,imitating the structural design of metamaterials,the all-dielectric absorber composed of the traditional dielectric materials are designed to improve the impedance matching and achieve high performance of microwave absorption.Then,the concept of coding is introduced and the structure units are coded to realize the broadband RCS reduction.Firstly,Utilizing the deionized water,a flexible all-dielectric structural absorber was manufactured by the 3D printing technology.The absorber shows the broadband microwave absorption properties,and the experimental results show that the frequency band where the absorption rate is more than 90% is 5.9-25.6GHz.The high efficiency microwave absorption performance mainly benefits from the strong dielectric loss of water and the good impedance matching performance optimized by the structural design.Secondly,two kinds of structural units were designed based on the titanium dioxide/carbon nanotube composite,and the 2-bit coding structural absorber was formed by encoding the two units.The coding structural absorber possesses the properties of scattering and absorption.The electromagnetic interference generated by the units with different reflection phase characteristics results in the scattering of electromagnetic waves.The dielectric loss of composites provides the absorption properties for the coding structural absorber.The wideband RCS reduction can be adjusted by modulating the proportion of the constituent units,and the frequency band of the RCS reduction is 5.3-18 GHz.Finally,in order to further broaden the RCS reduction of 2-bit coding structural microwave absorber at low frequencies.We designed the 3-bit coding structural microwave absorber.The wideband RCS reduction mainly depends on the amplitude modulation of the coding units.By modulating the different proportion of three kinds of units,the 3-bit coding structural microwave absorber with different performances can be realized,so as to meet the application requirements of different environments.In this paper,three kinds of structural absorbers achieved the broadband and highstrength electromagnetic stealth.Although,the composition material does not have good absorbing property,the design of the structure realizes the wide band absorption and the coding design increases the scattering properties,so as to reduce the radar cross section more effectively.Meanwhile,the hollow-out structural design also provides the possibility to realize the small surface density.The design idea of coding structural absorber provides more possibilities for the development and important reference for the application of the absorber.