Design of compact multiband fractal antenna for WLAN and WiMAX applications

In this paper, broadband and multiband design approaches are proposed to produce antennas that can serve for various wireless technologies using different frequencies from 2.3 to 5.0 GHz, covering WiFi, WLAN frequencies at 2.4-2.48 GHz, as well as WiMax frequencies at 2.40-2.48 GHz, 2.49-2.59 GHz, 3.5-3.8 GHz. Introducing fractal concept to the star-shaped microstrip antenna, Koch curve antenna is designed. The Koch island fractal patch antenna is introduced in order to reduce the antenna size. By space-filling property of fractal geometry, this antenna reveals lower resonant frequency. There is a reduction of resonance frequency from 2.43GHz to 1.78GHz i.e. around 27% with the proposed antenna compared to the triangular patch of the same size. Based on experimental result, it is found that as iteration and iteration factor increases the resonant frequency of this patch antenna decreases. Broad band and multiband operation with size reduction is obtained. To improve efficiency and bandwidth suspended configuration is used. A comparison of fractal antenna with conventional microstrip patch antenna is made regarding the bandwidth, return loss, VSWR, and gain. The antenna is simulated by the HFSS software.