PERFORMANCE COMPARISON INVESTIGATION OF THE WIDEBAND AND FRACTAL MULTIBAND BOWTIE ANTENNAS

In many applications, it is desirable to use a single antenna that can operate effectively at several tune frequencies instead of a several narrowband antennas. Fractal antennas have many advantages, and they are capable to fulfil these requirements. In this paper, the conventional bowtie antennas which are characterized as broadband antennas are redesigned to include the Sierpiniski fractal structures such that the required multiband operation can be fulfilled. The original bowtie antenna shape is repeated at different scales corresponding to the required frequency bands. Thus, the procedure for producing the modified fractal multiband bowtie antenna is simple. This simplicity in the configuration change makes the proposed fractal bowtie antenna very desirable in practice and it can used in the frequency -reconfiguration applications. Further, it can be precisely tuned to any number of frequency bands depending on the number of fractal growth. Three antennas are designed, and their performances are analysed. The first one is a simple narrowband dipole; the second one is a broadband bowtie, and the third one is a Sierpiniski fractal multiband bowtie antenna. Their performances in terms of return loss, radiated power, gain and the directivity are extensively studied and compared using both MATLAB simulation and CST full -wave modelling software. The designed second -stage fractal bowtie has multiple resonant frequencies at different scale copies of the structure at 2.4, 9.2 and 17.4 GHz.