Abstract:

In order to apply the slot .antenna to the Radio Frequency Identification (RFID) tag , a new method to design the slot antenna for RFID tag is first proposed. In this method , the impedance expression of mutual-patch antenna is adopted to calculate the impedance of mutual-patch dipole antenna according to the impedance of the slot antenna to be designed. Next , the profile of the dipole antenna is determined , and two slot antennas respectively with even and odd symmetries are presented for RFID tag at ultra-high frequency band. Then , the simulation is performed to present the curves of impedance and retum coefficient (S lI) versus frequency and the radiated pattem. Fabricated antennas are finally produced according to the simulated results. The results of design , simulation and measurement indicate that the design method is simple , clear and efficient , that the performance of the odd-symmetry slot antenna is better than that of the even-symmetry one , and that the simulated results accord well with the measured ones.

Key words: Radio Frequency Identification, tag antenna, slot antenna, mutual-patch antenna, impedance relationship, method of moment