基于传统谐振开口圆环频率选择表面（FSS），在有限元方法和半谐振圆环周期孔径结构的基础上，利用Floquent周期条件模拟无限空间单元，通过频域求解器得到该结构的散射参数和带通特性。将该结构单元的形状拓展成上下表面为反向开口的月牙形双层结构并优化出顶部传输通带平坦的多层半谐振环耦合结构FSS。仿真结果表明，横磁波垂直入射时，半谐振环结构的谐振频率稳定在9 THz，中心频率处的回波损耗为-22 dB，且具有较好的角度稳定性。双层月牙形结构在谐振点5.9 THz、10 THz和11.7 THz处可实现多窄带带通，多层FSS结构在6.35~9.35 THz频段内的传输系数低于-3 dB，具有良好的极化稳定性，为FSS在太赫兹无损检测、通信及传感等领域内的应用提供了理论依据和技术支撑。

In this paper, based on the frequency selection surface (FSS) of the traditional resonant split ring, on the basis of the finite element method and the semi-resonant ring periodic aperture structure, the Floquent period condition is used to simulate the infinite space element, and the scattering parameter and bandpass characteristics of the structure are obtained through the frequency domain solver. The shape of the structural unit is expanded to a crescent-shaped double-layer structure with reverse openings on the upper and lower surfaces, and the FSS of a multilayer semi-resonant ring coupling structure with a flat top transmission passband is optimized. The simulation results show that when the transverse magnetic wave is incident vertically, the resonant frequency of the semi-resonant ring structure is stable at 9 THz, the return loss at the center frequency is -22 dB, and it has good angular stability. The double-layer crescent-shaped structure can achieve multiple narrowband passbands at the resonance points of 5.9 THz, 10 THz and 11.7 THz, respectively. The multi-layer FSS structure has a transmission coefficient of less than -3 dB in the frequency range from 6.35 THz to 9.35 THz, and has good polarization stability. It provides a theoretical basis and technical support for the applications of FSS in the fields of terahertz non-destructive testing, communication and sensing.