Design and Experimental Validation of a Multifunction Single Layer UHF-RFID Tag Antenna

In this paper, we report a new design of a multifunction RFID tag antenna operating in the European band (865-868.5MHz) and the North American band (902-928 MHz) separately. The multifunction behavior can be achieved by changing the position of the RFID chip. It is found that at each feeding position, the RFID tag antenna can operate separately on both bands. The characteristics of the proposed design including S-parameters, impedance and reading range pattern have been investigated using simulation software CST Microwave Studio and experimental results. Further insight into the mechanism radiation is sought through the investigation of the current density and the equivalent circuit model. The tolerance of this design on various background materials is also investigated experimentally. The measured and simulated results show good agreement, providing a simple and low-cost design.