STACKED SIERPINSKI CARPET FRACTAL ANTENNA FOR X-BAND APPLICATIONS

Abstract

The current use of fractal geometries has significantly impacted many areas of science and engineering; one of which is antennas and their applications. Antennas using fractal geometries for various telecommunications applications are already available in market commercially. The use of fractal geometries had been shown to improve several antenna features to varying extents. In terms of performance as antenna elements, fractal shaped geometries are believed to result in multi-band and wide-band characteristics and also, reduction of antenna size. Although the utility of different fractal geometries varies in the aspects as mentioned above, nevertheless they are among the primary motives of fractal antenna design. For example, Sierpinski gaskets and carpets have been widely reported and their multiband characteristics have been linked with the self-similarity of the geometry. However, this qualitative explanation may not always be realised with all fractal shapes and geometries. A quantitative link between multiband and wideband characteristics of the antenna and a mathematically expressible feature of the fractal geometry is needed for design optimization. In this thesis, characterisation and analysis of the fractal shapes and correspondingly their antennas is done. A study of fractal geometries and have studied their multiband behaviour using the Sierpinski carpet fractal geometry, in particular, has been done. The concept of stacking of antennas is applied to Sierpinski Carpet, and the change in characteristics with that is studied and analysed. Next, realization of new fractal geometry as an antenna, which can be used in X band applications like amateur radio and military communication satellites (although high power requirements are needed here). The return losses and radiation patterns of these antennas are analysed in detail.