Design of the tree-shaped UWB antenna using fractal concept

In this paper, we have proposed a novel tree-shaped ultra-wideband antenna for UWB applications. We have used the partial ground plane technique and the fractal concept to achieve an ultra-wideband impedance matching. It is found that as the number of iteration increases, the lower-edge of the impedance bandwidth is moved to the low frequency and the level of the impedance matching over the operating frequency band(3.1 similar to 4.8 GHz) is improved. Prototypes of the proposed antennas have been successfully implemented and good radiation characteristics in the operating frequency bands have been achieved. The effect of the angle between upper and lower trapezoids on the return loss was also studied.