Wideband modified dipole antenna for passive UHF RFID tags

In this paper, a new modified wideband dipole antenna for passive UHF RFID is designed, simulated, fabricated and tested. The modification is done by adding vertical and horizontal stubs to the structure of the ordinary dipole antenna to reduce its length and broaden its bandwidth. IE3D full-wave electromagnetic simulator is used to simulate the modified dipole and compare it with the ordinary dipole antennas. The results showed that the modified dipole is shorter by (14%) and has wider bandwidth by (274.55%) which makes it able to cover the entire frequency band dedicated for UHF RFID systems (860 MHz ~ 960 MHz). The modified dipole antenna is fabricated using PCB technology and its parameters are measured in an anechoic chamber. The effect of different materials on antenna performance also studied in this paper.