Design and Simulation of Koch Fractal Antenna Array for Mobile Communications

Abstract

With the advance of wireless communication systems and increasing importance of other wireless applications, wideband and low profile antennas are in great demand or both commercial and military applications. Multi-band and wideband antennas are also desirable in personal communication systems, small satellite communication terminals, and other wireless applications. Wideband antennas also find applications in Unmanned Aerial Vehicles (UAVs), Synthetic Aperture Radar (SAR), and Ground Moving Target Indicators (GMTI). Some of these applications also require that an antenna be embedded into the airframe structure traditionally, a wideband antenna in the low frequency wireless bands can only be achieved with heavily loaded wire an antenna, which usually means different antennas, are needed for different frequency bands. Recent progress in the study of fractal antennas suggests some attractive solutions for using a single small antenna operating in several frequency bands. The term fractal, which means broken or irregular fragments, was originally coined by Mandelbrot to describe a family of complex shapes that possess an inherent self similarity in their geometrical structure. Fractals found widespread use in many branches of science and engineering in a relatively short time. Electromagnetism, and in particular antenna design has also benefited from these concepts. Applying fractals to antenna elements allows for smaller, resonant antennas that are multiband/broadband and may be optimized for gain. In this thesis three elements Koch antenna array is proposed. the performance of three Element Koch array is simulated and results obtained are compared with single Koch antenna. It is found from the analysis that the Koch array improves the gain, directivity, Bandwidth and input impedance. The frequencies used in simulation are of mobile communication viz GSM 900 and GSM 1800 MHz.