Current projects
On-Body Fractal Antennas
Supervisor(s): Dr Rob Edwards
Fractals shapes are mathematical objects that exhibit self-similarity at all levels of scale. A magnified portion looks similar to an unmagnified portion. Magnifying fractal shapes continuously reveals finer and finer details which look like the previously scaled version of the object. Fractals also have the measure of having a non-integer dimension, known as the Fractal Dimension.
Because fractal shapes are very compact and can contain “infinite” length or volume whilst occupying a finite length or volume, it would appear that they are ideal shapes to make compact antennas. This is because antennas are defined by thier current paths and fractals can be optimised to have long current paths within a limited footprint. They also exhibit some of the properties associated with wide band antennas in that they can be made to be a function of angle rather than a function of electrical length. Also their self-similar nature would suggest that they should also show multi-band performance. The first reported use of fractals to make an antenna was reported by Kim and Jaggard in their paper titled, “The Fractal Random Array”, in the Proc. IEEE, Vol.74, No. 9, pp 1278-1280, 1986. Subsequent papers have furthered this research for applications mainly in the field of mobile communications.
Such antennas may be particularly suitable for antennas worn close to or on the surface of the body.
One novel and topical application of fractal antennas has been use in Ultra Wide Band Radio and in particular in their use for increasing the bandwidth of existing antenna designs such as bow tie, shield and Vivaldi type structures. This research will carry out a planned detailed study of modeling the most appropriate fractal shape for use in Ultra-Wide Band Radio.
The project has been sponsored by the council for refugee academics (CARA) and supports three Iraqi scholars.