Miniaturized Circularly Polarized Vicsekcross-Shaped Slot Antenna for UHF-RFID Reader Handset Applications

In this research, a circularly polarized antenna employing fractal slot geometry is proposed for UHF-RFID handset reader application. The proposed antenna consists of vicsekcross-shaped slot etched at diagonal axis to achieve circular polarization with a coaxial feed placed 45° with respect to the slot. The evolution of Vicsekcross shaped fractal slot is developed in different iteration stages for achieving wide impedance bandwidth covering U.S. UHF-RFID band with good axial ratio bandwidth performance. The single slotted reader antenna was investigated first followed by multi-slot antenna for size miniaturization, impedance bandwidth and axial ratio bandwidth performance. The impedance bandwidth and axial ratio bandwidth of the designed antenna were observed to be 25 MHz (903-927 MHz) and 7 MHz (911-917 MHz), respectively. Additionally, the designed antenna exhibited LHCP with a maximum measured gain of 2.9 dBic. The size of the final Vicsekcross-shaped four slot CP reader antenna is compact with dimensions of 57 × 57 × 1.6 mm
³
.