本文提出了一种基于椭圆形镂空石墨烯的太赫兹宽带可调超表面反射线偏振转换器，通过模拟仿真和法布里-佩罗多重干涉理论进行了验证。设计的超表面模型类似三明治结构，分别由顶层各向异性的椭圆形镂空石墨烯结构、中间介质层和底层金属板组成。仿真结果表明：当给定的石墨烯弛豫时间和费米能级分别为τ =1.0 ps, μc=0.9 eV 时，设计的超表面结构偏振转换率(PCR)在0.98 THz～1.34 THz 的频率范围内超过90%，相对带宽为36.7%。另外，在谐振频点1.04 THz 和1.28 THz，PCR 分别高达99.8%和97.7%，这说明设计的超表面可以将入射的垂直(水平)线偏振波转换为反射的水平(垂直)线偏振波。通过法布里-佩罗多重干涉理论进一步验证了该模型，理论预测与数值仿真结果吻合得比较好。此外，设计的超表面反射线偏振转换特性可以通过改变石墨烯的费米能级和电子弛豫时间来动态的调节。因此，设计的基于石墨烯的可调超表面偏振转换器在太赫兹通信、传感以及太赫兹光谱领域具有潜在的应用价值。

A terahertz broadband tunable reflective linear polarization converter based on oval-shape-hollowed graphene metasurface is proposed and verified by simulation and Fabry-Perot multiple interference theory in this paper. Our designed metasurface model is similar to a sandwiched structure, which is consisted of the top layer of anisotropic elliptical perforated graphene structure, an intermediate dielectric layer and a metal ground plane. The simulation results show that when the given graphene relaxation time and Fermi energy are τ=1 ps and μc=0.9 eV, respectively, the polarization conversion rate (PCR) of the designed metasurface structure is over 90% in the frequency range of 0.98 THz～1.34 THz, and the relative bandwidth is 36.7%. In addition, at resonance frequencies of 1.04 THz and 1.29 THz, PCR is up to 99.8% and 97.7%, respectively, indicating that the metasurface we designed can convert incident vertical (horizontal) linearly polarized waves into reflected horizontal (vertical) linearly polarized waves. We used the Fabry-Perot multi-interference theory to further verify the metasurface model. The theoretical predictions are in good agreement with the numerical simulation results. In addition, the designed metasurface reflective linear polarization conversion characteristics can be dynamically adjusted by changing the Fermi energy and electron relaxation time of graphene. Therefore, our designed graphene-based tunable metasurface polarization converter is expected to have potential application value in terahertz communication, sensing and terahertz spectroscopy.