Designation And Optimization Of New Frequency Selection Surfaces

Frequency selective surface (FSS) is a surface structure that has selective effects on the frequency of incident electromagnetic wave. Generally, FSS can be divided into two kinds, which are surface Mounted Devices (SMD) type and aperture type. When the frequency of the incident wave reaches FSS resonant frequency, the FSS will present total reflection effects (for SMD type) or total transmission effects (for aperture type). Hence, the FSS can be used as a space filter, and it has been widely used in materials for radar cover and stealth aircraft. The basic electromagnetic characteristics of FSS can be described by parameters such as the resonance frequency, the bandwidth of the passband or resistance bands, and the transmission of the resonance frequency, etc.. Meanwhile, the basic performance of the FSS is mainly influenced by cell size, arrangement manner and form of the incident wave. Wherein, as the incident wave changing, the effects of FSS can be described mainly by polarization stability and angular stability. Therefore, the quality of polarization stability and angular stability is an important index of FSS.To design miniaturizing FSS with high stability, the main work of this thesis can be summarize as below:Firstly, the working principle of FSS is introduced, the influence on the performance of FSS from the cell structure, cell size, periodic distance, and dielectric slab is discussed. Several common algorithms are introduced, and the basic technological process for designing FSS by HFSS soft is also introduced with a specific example.Secondly, to overcome the weakness of traditional FSS such as low performance on polarization stability, angular stability and miniaturizing designation, two new structures of unit compound type and curved structure type are proposed based on traditional cross structure, and numerical simulation is used to prove the superiority of the proposed structures.Thirdly, a new miniaturizing designation scheme is proposed by rotating the traditional cross structure and adding vertical sides. Meanwhile, a new scheme for improving the selectivity is proposed by adding new arms, which does not change the cell size. The HFSS soft is used to simulate the above two scheme, and the physical production is also accomplished. The validity of the two proposed schemes are proved by simulation results and measured results.Finally, the technological process of physical production of FSS and the basic measurement scheme is introduced.