In this paper, we propose an ultrabroadband chiral metasurface (CMS) composed of S-shaped resonator structures situated between two twisted subwavelength gratings and dielectric substrate. This innovative structure enables ultrabroadband and high-efficiency linear polarization (LP) conversion, as well as asymmetric transmission (AT) effect in the microwave region. The enhanced interference effect of the Fabry–Perot-like resonance cavity greatly expands the bandwidth and efficiency of LP conversion and AT effect. Through numerical simulations, it has been revealed that the cross-polarization transmission coefficients for normal forward (-z) and backward (+z) incidence exceed 0.8 in the frequency range of 4.13 to 17.34 GHz, accompanied by a polarization conversion ratio of over 99%. Furthermore, our microwave experimental results validate the consistency among simulation, theory, and measurement. Additionally, we elucidate the distinct characteristics of ultrabroadband LP conversion and significant AT effect through analysis of polarization azimuth rotation and ellipticity angles, total transmittance, AT coefficient, and electric field distribution. The proposed CMS structure shows excellent polarization conversion properties via AT effect and has potential applications in areas such as radar, remote sensing, and satellite communication.

提出了一种利用电磁超表面实现Ku波段(12~18 GHz)的低剖面反射型线性极化转换表面,该表面能对Ku波段的线极化电磁波进行正交极化旋转。给出了极化转换表面的设计原理,并对极化转换表面工作的物理原理进行了解释,通过仿真确定了极化转换表面谐振点的位置。测试结果表明,该线性极化转换表面在工作频带内可以实现80%以上的转换效率,具有转换效率高、尺寸小、厚度薄和结构简单等优点。