Design A Small Size Circular-Polarized Microstrip Antenna For Rfid Applications

the paper presents a small size circularly polarized microstrip patch antenna designed for radio frequency identification application. The designed antenna consist loop structure and partial ground plane. The circular polarization is achieved by feeding probe in both end of the loop antenna. Moreover, to increase the axial ratio bandwidth and polarization purity, a fashion of shifting ground plane is used. The shifted ground plane is using for diminished the overall surface current and achieving wider bandwidth with respect to axial ratio. The proposed antenna is lightweight, easy to design and low price. The simulation has been done using CST studio suits to calculate return loss, axial ratio, polarization and gain of the antenna. The final size of the antenna is 36mm*18mm*1.67mm which is operating at 920MHz frequency.