A Compact UWB Koch Fractal Antenna for UWB Antenna Array Applications

In this paper, compact ultrawideband (UWB) antennas (1-Element and 2-Element) are presented in order to demonstrate application of fractal geometry in UWB antenna design, which helps to improve the antenna characteristics in a given smaller area. Some features of Euclidean shape geometry are improved after the application of fractals at the edges of the polygon. It is demonstrated that the application of Koch fractal in the antenna design helps to achieve the desired miniaturization, compactness and wideband operability due to its self-similar and space filling characteristics. An analytical expression is provided to calculate the effective length and area of the structure with the increase in iteration's order. Its performance is further compared with other fractal geometries such as Minkowski and Sierpinski curve. It is observed that the proposed Koch fractal based antenna yields the widest bandwidth and better gain compared to other fractal geometry based antennas. In addition, the time-domain analysis of the antenna is performed in terms of fidelity factor and its values are better than 0.81. 1-Element antennas shows operational bandwidth from 2.3 to 13.2 GHz with a maximum gain value of 3.8 dB, whereas in case of 2-Element antenna operating bandwidth is 2.3-14 GHz with a maximum gain value of 7.2 dB. Moreover, the radiation patterns of the single element and 2-Element are nearly omnidirectional. These characteristics offer opportunities to explore the proposed UWB antenna for various applications such as WPAN, WBAN, etc.