An Investigation Into The Feasibility Of Designing Frequency Selective Windows Employing Periodic Structures (Ref. AY3922)

Summary

It is the conclusion of this feasibility study that frequency selective windows with good shielding characteristics can be constructed. At the moment, frequency selective surfaces (FSS) made from silver paint (section 6), which is an opaque conductor, outperform optically transparent conductor FSS. It was observed, however, that FSS constructed from good quality, highly transparent in-house Indium Tin Oxide can have a satisfactory performance (section 8). These results are encouraging as the conductivity of the ITO can be reduced further (section 7).

For the FSS box, a 20dB attenuation performance was observed for the hexagonal element frequency selective windows used to construct it. We believe that the attenuation will increase further by employing a silver paint of higher silver concentration and hence conductivity than the 60% silver paint employed in this work (section 1). The microwave oven measurements in the presence of the FSS box demonstrated that there is a satisfactory attenuation, around 20 dB. The performance of the enclosure is improved by using absorbers to eliminate multipath propagation effects (section 9).

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