基于介质谐振器的薄导电板侧向回射增强设计

该文提出了基于无源介质谐振器腔内磁偶极子谐振的准超方向性再辐射，旨在增强薄导电板受到平面电磁波侧向照射时的后向散射截面。在平面电磁波激励下，设计适当的长方介质体中可诱导产生具有磁偶极子再辐射特征的混合电磁谐振模式。以长方介质体为基本谐振单元，将两个相同的介质体沿入射波传播方向紧密级联以组成一个超单元。超单元的两个介质体中的磁场强度与电场强度矢量均呈现相反的方向且相近的幅度，接近等幅而反相的内部场分布使超单元类似一个二元准超方向性磁偶极子阵列，由此产生的准超方向性再辐射有效地贡献于后向散射截面增强。进一步，由镜像原理，将超单元剖面厚度减半并加载于薄导电板表面。结果表明，剖面厚度仅为0.078λ₀的介质谐振器形成基于磁偶极子的准超方向性再辐射，在谐振频率处可显著修改薄导电板的侧向回射特性，进而在相对宽带宽角范围内对侧向入射波实现有效的后向散射截面增强。

Edge-On Backscattering Augmentation Design of Thin Conducting Plate Based on Dielectric Resonator

The quasi-superdirective reradiation based on the magnetic dipole resonance occurring within a passive dielectric resonator is presented to augment the backscattering cross-section of thin conducting plates at edge-on incidence. It is demonstrated that a hybrid electromagnetic resonance mode reradiating like a magnetic dipole can be induced within a properly dimensioned cuboid dielectric under the illumination of a plane electromagnetic wave. Using this cuboid dielectric as a basic unit cell, a supercell consisting of two identical dielectrics closely cascaded along the propagation direction of the impinging wave is formed. It is observed that both the magnetic and electric fields induced within the two dielectrics of the supercell exhibit opposite senses along with almost equal magnitudes. Because of the internal field distribution with opposite phases and almost equal magnitudes, the supercell acts as a two-element quasi-superdirective magnetic dipole array and the resultant quasi-superdirective reradiation effectively contributes to the backscattering cross-section enhancement. Further, the supercells with halved profile are loaded onto the surfaces of thin conducting plates according to the image theory. The results indicate that the magnetic-dipole-based quasi-superdirective reradiation assisted by dielectric resonators with a profile of only 0.078λ0 noticeably modifies the edge-on scattering characteristic of thin conducting plates. Effective augmentation of backscattering cross-section for edge-on incidence is therefore achieved within relatively wide band and angular ranges.