On the design of ultra wide band antenna based on fractal geometry

This paper presents ultra wide band circular fractal antenna. The antenna has been fed with coplanar waveguide (CPW) feed. This fractal antenna has been designed and fabricated on FR4 substrate ε_r = 4.3 and thickness h = 1.53 mm with initial diameter of solid circular disc 15 mm. The experimental result of circular fractal antenna exhibits the ultra wide band (UWB) characteristic from 3.295 GHz to 13.365 GHz corresponds 120.88 % impedance bandwidth. The first resonant frequency of fractal antenna shifted to 3.75 GHz in comparison to first resonant frequency 4.31 GHz of conventional simple circular disc monopole antenna. This indicates the size reduction of antenna. The measured radiation pattern of this fractal antenna is nearly omnidirectional in azimuth plane throughout the band. This type of antenna can be useful for UWB system and sensing applications.