Miniaturised Circularly Polarised Koch Fractal Antenna with Rotated Fractal Slot for RFID Applications

In this paper, a miniaturized Koch fractal antenna with rotated fractal slot is designed for RFID applications using ADS Software. The idea behind the rotated fractal slot is to provide multiband circular polarization. Circular polarization can be achieved by introducing asymmetrical Koch fractal curve on the boundary of microstrip patch antenna. The proposed antenna is designed on a RT-Duroid5880 substrate with a dielectric constant of 2.2 and a thickness of 3.2mm. The impedance bandwidth of the proposed antenna design are found to be 97 MHz, 22 MHz and 406MHz at operating frequencies 2.6 GHz, 3.5GHz and 5.7GHz respectively. The three bands of frequencies of the proposed antenna are inside RFID Super High Frequency (SHF) range (2.45-5.8GHz).