Many approaches have been developed over the years for designing compact and
multiband microstrip antennas. Recently, microstrip antenna design that exploits, in someway,
the `properties of fractal' to achieve these goals has attracted a lot of attention
(Douglas and Suman, 2003). The term `fractal' means broken or irregular fragments. Fractal
represents a class of geometry with very unique properties including: (1) self-similarity; (2)
fractional dimension; (3) formation by iteration; and (4) space filling. These properties can
further be exploited to design antennas which are miniaturized, have improved input
matching ability and are multiband/wideband. Various fractal shapes that possess
self-similarity have been applied to multiband or miniaturized antenna design
(Kuem, 2007). Most fractals have a self-similarity shape, which means that their shape is similar at different scales.
A fractal has a rough or fragmented geometric shape that can be subdivided into
parts, each of which is a reduced size copy of the whole. Fractals are generally self-similar
and independent of scale. This fractal property can be used to realize antenna designs over
a large band of frequencies.
Also, in modern wireless communications more and more systems are
introduced which integrate many technologies and are often required to operate at multiple
frequency bands. For such applications, use of fractal self-similar pattern is one of the solutions
for designing antennas (Werner, 1995). Also to achieve wideband, the H-Shaped
antenna was proposed by Abdel Fattah et al. (2002). |
