单元形状的微小改变对频率选择表面电性能的影响

为考察单元形状在频率选择表面(frequency selective surface,FSS)电性能中所起的作用,根据缝隙电场的分布,研究了带通型FSS的单元形状改变对频率选择特性的影响。研究发现,部分单元的缝隙电场0点处的形状改变会显著影响FSS的频选特性,这一现象很难用缝隙电场的分布规律来分析,却可以用FSS层上表面电流反向模式来解释。在研究表面电流分布与谐振的联系的基础上,提出了FSS结构谐振与表面电流反向之间的对应关系:FSS的每一个谐振点都对应着单元上一个区域的表面电流反向;只要缝隙电场的分布或表面电流反向模式相同,FSS结构的谐振特性就相同。应用这一结论可以将复杂单元FSS分解为简单单元来分析,也可以用来设计具有不同极化特征的FSS结构。

Influence of element shape's tiny change on electrical performance of frequency selective surface

In order to realize the role played by aperture shape in the electrical performance of frequency selective surface(FSS),the influence of the aperture shape’s tiny change on band-pass FSS is studied according to the laws of the aperture tangent electric field distribution.The results show that the shape change in the zero points of aperture tangent electric field of some special elements influence the electrical performance of FSS tempestuously.This phenomenon is hard to explain by the laws of aperture tangent electric field distribution but has a close relationship to the mode of the currents distribution on the unit cell.On the base of the research on the induced currents distribution,the relationship between resonance and induced currents distribution is presented.This relationship can be described as that every resonance is corresponding to a reverse of induced current on some area of the conduct layer which is defined as the current reverse mode in this study.The electrical performances will be the same as long as the electric field distribution or the current reverse modes is similar.This conclusion can be applied to solve complicated elements FSS and design FSS structures with different polar properties.