【作者】 林莉；

【导师】 江建军；

【作者基本信息】 华中科技大学 ， 电磁场与微波技术， 2021， 硕士

【摘要】 隐身能力是新一代军用武器的重要特征之一,隐身技术发展在军事领域具有重要意义,其关键在于降低目标的雷达散射截面(Radar Cross Section,RCS)。目前研究多数集中在镜面散射的RCS缩减问题,而在实际应用中,对于目标的细长部位,通常还存在较强的表面行波散射,不可忽视。本研究以高阻抗表面(High Impedance Surface,HIS)为研究对象,同时结合频率选择表面(Frequency Selective Surface,FSS)吸波结构的应用,抑制了表面行波散射及镜面散射两个主要贡献源,实现了正入射兼顾掠入射的宽角域单站RCS缩减控制效果。本文的主要研究结果如下:首先,系统地研究了细长平板的单站RCS散射特征,重点分析了细长平板的表面行波散射特征及其形成原因,提出了一种低剖面螺旋通孔的HIS结构来抑制表面行波。进一步,设计了HIS结构与FSS吸波体的双层复合结构,上层FSS吸波体缩减镜面角域RCS,下层HIS缩减掠入射角域RCS,实现了宽角域RCS缩减性能。仿真和实验结果表明,双层复合结构正入射在1.0 GHz～4.5 GHz实现10 d B以上的RCS缩减,同时掠入射14°时在0.85 GHz～3.4 GHz内实现10 d B以上的RCS缩减。其次,分析了HIS结构在正入射时的作用机理,研究了金属通孔在不同入射情况时的作用,证明了在正入射时HIS结构与FSS吸波体的工作机理一致。根据正入射与掠入射的等效电路分析,提出一种兼顾正入射与掠入射RCS缩减的新型单层HIS结构,并通过RCS仿真以及实验验证了新型HIS结构的宽角域RCS缩减性能。研究表明,此新型HIS结构在1.3 GHz～4.5 GHz频段内不小于70°入射角范围内实现有效的RCS缩减,总厚度仅为20 mm。综上所述,本研究揭示了细长平板的RCS散射机理,提出了两类有效抑制镜面散射及表面行波散射的HIS结构,在L、S波段实现了宽角域RCS减缩,为实现高价值目标的隐身特性提供了设计基础。更多还原

【Abstract】 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.更多还原