Numerical and experimental investigations are presented for a dual-band frequency selective surface (FSS) with perfectly conducting rectangular patch elements. In the first step two single-band FSS screens were designed to obtain resonant frequencies at 9.5 GHz and 10.5 GHz, each one with about 1.5 GHz bandwidth at -3 dB. In the second step these single FSS screens were cascaded and separated by an air gap layer to achieve a dual-band response. The Moment Method is used to analyze the structures single band. After this, a numerical cascading technique is used to analyze the effect of the air gap between the cascading structures. Numerical and measured results were compared and a good agreement was obtained.

This work presents an analysis of frequency selective surfaces (FSSs) with Dürer's pentagon pre-fractals patch elements. The proposed FSSs are composed by a 2-D periodic array of metal pre-fractals elements printed on a dielectric substrate. A parametric analysis is performed using Ansoft Designer commercial software in terms of the FSS periodicity and of the fractal iteration number used in the FSS elements. The structures are proposed to behave like stop-band spatial filters and exhibit interesting features to be used in the design of compact FSSs with broadband or dual band responses.

This paper presents the application of frequency selective surfaces in antenna arrays as an alternative to improve radiation parameters of the array. A microstrip antenna array between two FSS was proposed for application in WLAN and LTE 4G systems. Several parameters have been significantly improved, in particular the bandwidth, gain and radiation efficiency, compared with a conventional array. Numerical and measured results are presented.