Frequency selective surfaces for aerospace applications

Frequency selective surfaces (FSS) are an important application in many engineering sectors. In particular, it is useful for radomes, filters and radar communications. Traditional FSSs are constituted by two possible configxuations periodically perforated metallic screens, or arrays of metallic patches printed on dielectric substrates. Aeronautic, military and naval applications are the typical technological fields involved in the FSS developments. 

With a specific design of the traditional FSS, as a result of the Floquet theorem, it is possible to select a unique frequency value for the filter. By solving Maxwell equations, it is possible to determine the theoretical electromagnetic FSS behavior. However, considering the complexity of the phenomena involved, it is only possible to perform a realistic characterization of the FSS with an experimental test. 

New kinds of FSS have been introduced that incorporate nanotechnology. In fact, using particular matrices (thermoplastic and thermosetting polymeric resins, silicones, etc.) with homogeneously dispersed, nanoparticles (structured and non-structured) it is possible to produce a material necessary for the electromagnetic, stmctural and mechanical requirements. In contrast, traditional FSSs provide only electromagnetic properties. 

The novel complex medium is an amorphous ensemble of micro- and nanospheres composed of a lossy core, coated with a highly resonant dielectric layer and embedded in a dielectric host (a polymeric matrix). This is an innovative application of nanotechnologies in the electronic field. 

With these iimovative nanostructured FSSs, it is necessary to develop appropriate software useful for evaluating the electromagnetic and mechanical behavior. 

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