Traditional circuit analog absorber (CAA) composed of identical resistive patch elements suffers from narrow bandwidth. A novel absorptive coding metasurface is constructed by introducing another kind of resistive patch element into the CAA. The newly introduced elements resonate at higher frequency than the original patch elements do so that a reflection phase difference of about 180° is produced above the original absorption band between the two kinds of elements. Hence the metasurface achieves a much wider low-RCS band of which the lower and higher sub-bands attribute mainly to electromagnetic absorption and anti-phase cancellation, respectively. A preliminary and an advanced designs of the proposed metasurface are presented. Both of these two designs employ the same element configuration, but adopt different element layout schemes, for one is partitioned distribution and the other is random coding. Full-wave simulation and experimental results of the two designs confirm the characteristic of the proposed metasurface in broadband and polarization-insensitive monostatic RCS reduction under normal incidence. As for the preliminary design, in particular, the low-RCS bandwidth ratio versus electrical thickness reaches to 40.792, which is comparable with or even superior to those for most of the existing metasurfaces using compound RCS reduction mechanism. Meanwhile, the advanced design also exhibits broadband bistatic low-RCS property, and keeps a stable specular RCS reduction performance with regard to incident elevation angle up to 30°. The proposed metasurface features simple structure, light weight, low cost and easy fabrication, making it a competitive candidate in applications such as radar stealth and electromagnetic compatibility.

由相同的电阻贴片元件组成的传统电路模拟吸收器（CAA）带宽窄。通过将另一种电阻贴片元件引入CAA，构造了一种新颖的吸收性编码超表面。新引入的元件以比原始贴片元件更高的频率谐振，从而反射相位差约为180 °在两种元素之间的原始吸收带之上产生。因此，超颖表面实现了更宽的低RCS频带，其较低和较高的子频带分别归因于电磁吸收和反相抵消。介绍了拟议的超颖表面的初步设计和高级设计。这两种设计都采用相同的元素配置，但采用不同的元素布局方案，因为一种是分区分布，另一种是随机编码。两种设计的全波仿真和实验结果证实了拟议的超宽带的特征和法向入射下偏振不敏感的单静态RCS降低。对于初步设计，尤其是低RCS带宽比与电厚度的比值达到40.792，使用复合RCS还原机制，对于大多数现有的超颖表面而言，其性能可与之相比甚至更高。同时，先进的设计还展现了宽带双基地低RCS特性，并且在入射仰角最大为30时保持了稳定的镜面RCS降低性能。°。所提出的超颖表面具有结构简单，重量轻，成本低和易于制造的特点，使其成为雷达隐身和电磁兼容性等应用中的有竞争力的候选人。