A multiband reflective linear-polarization (LP) converter based on an anisotropic metasurface is proposed. The unit cell of the metasurface is composed of a hollow oval sheet and a rectangle patch. Simulation results show that the converter can convert LP wave to its orthogonal state and the polarization conversion ratio (PCR) is above 90% in four frequency bands (4.60–12.27 GHz, 13.79–13.90 GHz, 14.61–14.69 GHz, 15.44–15.52 GHz). Interestingly, the relative bandwidth of first band reaches up to 90.9%, which is even broader than most single-band polarization conversion metasurfaces. Furthermore, we analyze the physical mechanism of polarization conversion of the metasurface, and simplify the derived formulas to make approximate calculations for co- and cross-polarization coefficients. The proposed formulas have better applicability than the equations in previous work. The laboratory sample is fabricated, and we have experimentally characterized our idea in microwave region. This design can advance applications in microwave sensors and mm-wave systems.

提出了一种基于各向异性超表面的多波段反射线性偏振 (LP) 转换器。超表面的晶胞由空心椭圆片和矩形片组成。仿真结果表明，该转换器可以将LP波转换为其正交状态，并且在四个频段（4.60-12.27 GHz、13.79-13.90 GHz、14.61-14.69 GHz、15.44-15.52 GHz）的偏振转换比（PCR）均在90%以上）。有趣的是，第一波段的相对带宽高达 90.9%，甚至比大多数单波段偏振转换超表面还要宽。此外，我们分析了超表面极化转换的物理机制，并简化了推导出的公式以对共极化和交叉极化系数进行近似计算。所提出的公式比以前工作中的方程具有更好的适用性。实验室样品已经制作完成，我们在微波领域对我们的想法进行了实验表征。这种设计可以推进微波传感器和毫米波系统中的应用。