Research Of All-dielectric Frequency Selective Surfaces Based On Metamaterial Theory

A Frequency Selective Surface(FSS) is a periodically structure arranged in two-dimension infinite array, which is basically composed of patch or aperture elements. FSSs have unique filtering characteristic to incident electromagnetic waves with different incidence angles and polarizations. Working as spatial filter, FSSs have been extensively used in electromagnetic and communication domain.Domestic and foreign scholars have done a lot of research on the traditional frequency selective surfaces. Traditional frequency selective surfaces usually have a narrow operating band and often with complex structures. Metallic grids, however, are problematic at very high power. Arcing occurs at field concentration points and heating occurs due to ohmic losses experienced by strong currents in the conductors. Losses will increase, and the passband characteristic of the FSS will deteriorate. In view of these situations, the main works of this article can be summarized as follows:Firstly, this thesis present the basic concept and working principle of FSSs, including analytic methods, design procedures. We give some examples of the FSS applications in the field of elctricmagnetic and communications. Briefly introduction of the electromagnetic simulation software that we used is also presented.Secondly, the full wave simulation software(CST) is used to simulate several classical FSS unit shapes, and some factors are considered for the FSS frequency response, such as the shape, size, space, arrangement, media loading, and even the polarization and incident angle of incidence waves,and so on.Finally, in response to these shortcomings of the traditional frequency selective surface,an alldielectric frequency selective surface with switching feature is develped for high power microwaves. This structure consists of two layers dielectric cylinder array. When the two arrays are clapped together, it shows the band-stop character; when we separate two arrays for a little space, it becomes a band-pass FSS. The dielectric cylinder array works without metallic electromagnetic resonances, which make it a broad band response and easy to be implemented. Both the simulated results and experiment results demonstrate that the all-dielectric FSS structure has a relatively stable angle and polarization characteristics.