Frequency Selective surface (FSS) are planar periodic
structures that behave like filter to electromagnetic energy. The
surface is assembled with identical patch or aperture
conducting elements repeating periodically in either a one- or
two-dimensional array [7, 8]. FSS controls the flow of the
electromagnetic energy that passes through. As a result, someof the frequency constituents of the wave are blocked, and some
pass through the FSS fence. In another perspective, an FSS is
analogous to a filter in circuit theory. Besides, FSS structures
are also called spatial filters in electromagnetic engineering.
Based on the element geometry, FSSs can be classified as band
stop, band pass, low pass, and high pass filters. There have a lot
of research in analysis of the FSS presented here is based on the
equivalent circuit model [9, 10]. FSS can be equivalently
interpreted as a resonant circuit consisting of a parallel L-C
resonator. Equation (1) shows the equation of resonant
frequency.