A fractal based FSS with dual band characteristics

The design of multiband frequency selective surfaces (FSS) has attracted much attention. It is clear that by arraying dual-band elements it is possible to obtain a dual band FSS. On the other hand, the multiband properties of antennas designed using fractal shapes have been previously demonstrated. It appears a natural choice to explore the feasibility of a dual-band FSS based on fractal elements. A preliminary design of a FSS based on the Sierpinski gasket dipole is presented. The FSS is designed by periodically arraying a two iteration Sierpinski dipole. A fundamental constrain of this approach is the band limitation imposed by the excitation of grating lobes. It is for this reason that the design of a dual band FSS has been addressed, instead of a more general multiband design. The performance of the Sierpinski FSS is compared with a design based on the bow-tie element. It is been shown that it is possible to exploit the multiband properties of fractal antennas to design a dual band FSS.