Analysis and Design of Fractal Antennas

Abstract

The increasing importance and advancement of wireless communication systems have an increasing demand of low profile and wideband/multiband antennas for both the commercial and military applications. One possible approach in this regard is to use fractal geometries to meet a particular design goal. Combination of fractal geometry with electromagnetic theory leads to the new and innovative antenna designs. Fractal antenna theory uses fractal geometry which is a natural extension of classical Euclidian geometry. The antenna designs based on the fractal patterns provides a simple and efficient method for obtaining the desired compactness and multi-band properties and offer solutions to a number of limitations encountered by classical antennas. In this thesis the basic concepts of fractals and their emergence as antennas is studied. Two basic categories of antennas i.e. wire and patch antennas using five different fractal structures (Koch fractal, Sierpinski triangle and gasket, Minkowski and Sierpinski Carpet Triangle) have been designed and their performance is analyzed. Method of Moments (MOM) numerical simulation is used to simulate each antenna. The simulation results obtained for various parameters for these antennas show certain distinguished characteristics. These antennas designs have increased effective length and at the same time occupy less geometrical space. Decreased input impedance, a low voltage wave standing ratio, increased bandwidth and multiband performance obtained for these antennas make them efficient candidates for excellent alternative to traditional antenna systems used in mobile wireless receivers.