基于吸聚一体的低散射传输型透镜设计

通过传输型超表面透镜与电路模拟雷达波吸收器的集成设计，提出了一种兼具透射波前变换与带外雷达散射截面减缩特性的微波复合材料设计方法。透镜采用亚波长分布的周期性单元，由梯度相位补偿对透射波进行调节，进而获得平面波前与球面波前之间的互易变换。并且，使用透镜在波前变换频带以外低频端的反射特征，结合单个有耗层设计，构造了电路模拟吸波器。选用一副缝隙耦合馈电的微带贴片天线单元作为初级馈源天线，观察到复合材料的波前变换特性可在宽频带范围内产生主瓣增益增强效果。与透镜相比，电路模拟吸波器的引入使得复合材料针对TE与TM极化分别可在130.68%与155.11%的频率范围内获得雷达散射截面减缩效果。通过全波模拟和实验测量，验证了辐射增益增强与雷达散射截面减缩效果，表明了复合材料吸聚一体设计的有效性。

Design of low-scattering transmissive lens based on integration of absorption with focusing

Based on the integration of a transmissive metasurface lens with the circuit analog absorber, the design of a microwave composite material with characteristics of both transmissive wavefront conversion and out-of-band radar cross-section reduction is proposed and examined. With the refraction tuned by gradient phase compensation, the lens consisting of sub-wavelength spaced layers of periodic inclusions exhibits a reciprocal conversion between planar and spherical wavefronts. Moreover, the responses of the lens at the lower side of the wavefront conversion band are used to construct a circuit analog absorption profile containing one lossy layer. By using an aperture-coupled microstrip patch antenna element as the primary feeding antenna, main lobe gain enhancement over a wide band is observed as a result of the wavefront conversion of the composite material. In comparison with the lens, the introduction of the circuit analog absorption profile produces radar cross-section reduction over the bandwidths of 130.68% and 155.11% for TE and TM polarizations, respectively. The full-wave simulation and experimental measurement demonstrate the enhanced radiation gain and reduced radar cross-section and illustrate the validity of the composite material design with integrated absorption and focusing.