Liu Kaiyue, Wang Guangming, Cai Tong, Li Tengyao
Opt Express. 2020 May 11;28(10):14995-15005. doi: 10.1364/OE.393388.
Metasurfaces (MSs) offer us an efficient way to control electromagnetic wave polarization due to its capability of flexible wave manipulation and compact configurations. However, the design of dual-band polarization conversion MS with high angular stability is still a challenge, especially in transmission geometry. Here, we propose a dual-band linear-to-circular (LTC) polarization conversion MS with high angular stability by using an array of multi-resonance meta-atoms. The meta-atom consists of two outer double split-ring layers and a central bar layer with circle-slot and can realize circular polarization at two bands with high efficiency and angular stability. The MS can transform the x-polarized wave into right-hand circular polarization (RHCP) at lower band and left-hand circular polarization (LHCP) at higher band and an opposite role for the y-polarized wave. The results show that the MS operates with insertion loss less than 0.5 dB and 0.3 dB and axial ratio below 3 dB in the frequency range of 9.05-9.65 GHz and 12.55-13.1 GHz, respectively. Moreover, our MS is insensitive to the oblique incident waves and can operate at high performance with the incident angle less than 55°. The proposed MS provides a new avenue to design meta-devices with dual frequency property and also high angular stability.
超表面（MSs）因其灵活的波操控能力和紧凑的结构，为我们提供了一种控制电磁波极化的有效方法。然而，设计具有高角度稳定性的双频极化转换超表面仍然是一个挑战，特别是在透射几何结构中。在此，我们通过使用多共振元原子阵列提出了一种具有高角度稳定性的双频线性到圆极化（LTC）转换超表面。该元原子由两个外部双裂环层和一个带有圆形槽的中心条形层组成，能够在两个频段高效且稳定地实现圆极化。该超表面可以在较低频段将x极化波转换为右旋圆极化（RHCP），在较高频段转换为左旋圆极化（LHCP），对于y极化波则起到相反的作用。结果表明，该超表面在9.05 - 9.65 GHz和12.55 - 13.1 GHz频率范围内的插入损耗分别小于0.5 dB和0.3 dB，轴比低于3 dB。此外，我们的超表面对斜入射波不敏感，在入射角小于55°时仍能高效工作。所提出的超表面为设计具有双频特性和高角度稳定性的超器件提供了一条新途径。
