Detailed Analysis of a Novel Fractal Monopole Antenna for UWB Applications with Notches for WLAN Rejection Using Two Different Approaches

Abstract

In this paper, a novel fractal monopole antenna is analyzed in details. Initially, the basic generator structure is designed in which the effect of using different grounds is studied. A 50 ohm microstrip feed having width 3 mm is used to excite the antenna. The basic generator antenna exhibits a wide bandwidth of 10.24 GHz between 3.31 GHz to 13.55 GHz. The antenna shows stable radiation patterns at different frequencies within the UWB frequency range. The later part of the paper is mainly concerned with the final iteration of the basic generator structure. The final novel antenna has a bandwidth of 11 GHz in the frequency range of 3.4 GHz-14.4 GHz. Moreover two different methods are adopted for rejecting WLAN frequency band: A) an inverted U shaped structure with appropriate dimension is etched out from the patch to realize a stop band between 4.87 GHz to 5.89 GHz B) In this case a similar kind of inverted U shape structure having thickness 0.2mm is inserted in the microstrip feed in order to obtain a notch between 4.8 GHz to 6.6 GHz. Effect of variation of the strip width as well as different dielectrics is analyzed in details. The final antenna also exhibits stable radiation patterns at different frequencies within the UWB range. The measured results are in well agreement with the simulated results. All the designs and analysis is carried out in HFSS 14.