圆环单元FSS对改善吸波体雷达吸波特性的影响

设计了圆环单元的频率选择表面（FSS）结构，并将该结构置于吸波材料中构成了复合吸波结构。利用谱域法对该结构进行数值模拟，计算出频率为2～16GHz微波波段的反射系数，并研究了圆环单元尺寸和排布周期对其吸波特性的影响。结果表明：当圆环单元FSS的单元间距为10mm，单元尺寸为3．3mm时，其共振频率的反射率由-8．15dB降低为-14．54dB，-5dB吸波带宽由1．2GHz拓展为3．05GHz；且随圆环单元尺寸增大，共振反射率增加；随单元排列周期增加，吸波材料带宽增大。结果表明，利用FSS可以明显改善吸波材料涂层的吸波性能，通过凋整相关参数可以获得所需的复合吸波结构，拓展FSS在吸波材料中的应用范围。

Influence of ring FSS on improving characteristics of radar absorbing materials

A ring-unit FSS is designed and put into absorbing materials to form the composite FSS absorbing structure, then the structure is numerically simulated through the spectral domain approach. The reflection coefficient of the structure at a microwave band in 2-16 GHz is calculated and the influence of ring-unit's sizes and aligning cycles on absorbing characteristics is studied. The results show that when the ring-unit FSS's unit spacing is 10 mm and unit size is 3.3 mm, the resonance frequency reflectivity decreases from -8.15 dB to -14.5 dB, and the absorbing band with whose reflectivity is larger than -5 dB broadens from 1.2 GHz to 3.05 GHz. Meanwhile, the resonance frequency reflectivity increases with the increasing of ring-unit size, and the absorbing material's bandwidth expands with the expansion of unit aligning cycles. Experimental results indicate that the FSS can be used in absorbing materials to improve its absorbing properties. Moreover, the required composite FSS absorbing structure can be obtained by adjusting the corresponding parameters, which expands the application scope of FSS in absorbing materials.