Reduction Control Technique Of Wide-angle Radar Cross Section For The Slender Plate With High Impedance Surfaces

Stealth capability is one of the important features in new generation military weapons.The development of stealth technology plays an important role in the military field,and reducing the radar cross section(RCS)of the target is the key point.Nowadays,most researches are focusing on the problem of specular scattering RCS reduction.However,there is usually strong surface traveling wave scattering for the slender part of the target in the practical applications,which cannot be ignored.This thesis is based on High Impedance Surface(HIS),combined with Frequency Selective Surface(FSS)absorber to suppress the surface traveling wave scattering and the specular scattering.The wide-angle monostatic RCS reduction control is realized at both normal incidence and grazing incidence.The main research results of this thesis are outlined as follows:First of all,the monostatic RCS scattering characteristics of the slender plate are systematically studied.Attention is paid to the analysis of the surface traveling wave scattering characteristics and causes of the slender plate.Hence,a low-profile HIS structure with helical via is proposed to suppress the surface traveling wave.Furthermore,a double-layer composite structure combined HIS structure and FSS absorber is designed.The upper FSS absorber reduces the RCS of the specular incidence,and the lower HIS reduces the RCS of the grazing incidence,thus,the RCS of wide-angle range reduction is obtained in this composite structure.Simulation and experimental results show that the double-layer composite structure achieves an RCS reduction of more than 10 d B in 1.0 GHz?4.5 GHz at normal incidence,and an RCS reduction of more than 10 d B in 0.85 GHz?3.4 GHz at grazing incidence of 14°.Then,the mechanism of the HIS structure at normal incidence is extensively analyzed,and the role of the metal via at different incident conditions is investigated in detail.It is proved that the mechanism of HIS structure and FSS absorber is consistent at normal incidence.According to the analysis of the equivalent circuit at normal incidence and grazing incidence,a novel single-layer HIS structure is discussed,which takes the RCS reduction of normal incidence and grazing incidence into account.The RCS reduction of wide-angle range of the proposed HIS structure is respectively examined through simulation and experiments.Reserch shows that effective RCS reduction more than the range of 70° incidence angle in 1.3 GHz?4.5GHz frequency band is achieved by the novel HIS,with a total thickness of novel HIS structure only 20 mm.In summary,the RCS scattering mechanism of the slender plate was founded,two types of HIS structure were put forward,which can effectively suppress the specular scattering and the surface traveling wave scattering.The RCS reduction of wide-angle range in the L and S bands were also designed in detail.As a result,this provides a design basis for the realization of the stealth characteristics of high-value target.