为使大周期下带宽较窄的频率选择表面(FSS)结构透过率较高，以Y环单元为基础提出了一种提高通带透过率的新方法。该方法在周期单元内设置圆形孔径，通过增大占空比来提高透过率。运用谱域Galerkin方法数值分析了这种结构的传输特性，结果显示，确定R=0.5 mm，单元周期内圆孔个数为12时，中心频点10 GHz的透过率提高了0.11 dB。采用镀膜与光刻相结合的技术制备了相应的试验件，并进行了微波测试，测试值与计算值基本一致。开圆孔Y环的中心频点透过率在电磁波垂直入射的情况下为-0.62 dB，比对应Y环提高了0.21 dB，而在30°和45°倾斜入射的情况下，TE波的透过率分别为-0.66 dB和-0.81 dB，比对应Y环分别提高了0.32 dB和0.27 dB；-3 dB带宽分别为1 GHz和0.8 GHz，两种结构的带宽基本一致。得到的结果表明，提出的方法是大周期下提高通带透过率的一种行之有效的方法。

On the basis of Y loop elements, a new method to set circular slots on the periodic element to improve the narrow bandwidth of a Frequency Selective Surface (FSS) structure was presented. The FSS structure was calculated by Galerkin’s method in the spectral domain when the optimum radius was set to be 0.5 mm and the number of the circular slots to be 12, and the transmittance in the resonance frequency of 10 GHz has increased by 0.11 dB. The plane sample was fabricated by depositing coatings and a lithograph technology,and obtained measured values are in good agreement with the calculated values. The results show that the transmittance of this structure is about -0.62 dB at the resonance frequency,which has increased by 0.21 dB under the perpendicularity incidence compared with that of the Y loop without circular slot. Furthermore,the transmittances at TE 30°and 45°incidence are -0.66 dB and -0.81 dB, respectively,which has increased about 0.32dB and 0.27dB compared with those from the Y loop without circular slots.The bandwidth difference between the two structures is negligible, which are about 1 GHz and 0.8 GHz under TE 30°and 45°incidence, respectively. These results indicate that this method is an effective way to improve the transmittance of large periodic FSS structure at the resonance frequency.