Multi-band and miniaturized antenna design for ultra wide band applications with band rejection characteristic

In this paper, the combination of concentric square loop and the Koch curve fractal geometries based microstrip antenna design for ultra wideband (UWB) applications is presented. This fractal structure is implemented on a empty square. Three progressively concentric square loop is applied inside the empty square and a full square is applied to the center for the first iteration. Then, a Koch curve fractal is applied to the lines of the first iteration. The proposed antenna is miniaturized (44 × 43 mm2) and has multi-band characteristics. Simulation results show that the presented antenna has a reflection coefficient characteristic <; -15dB, 80% radiation efficiency, 4-6dBi antenna gain and omni-directional radiation pattern properties over the full UWB bandwidth (3.1 - 10.6 GHz) while showing the band-rejection performance in the frequency band of 4.75-6.75 GHz.