On the performance degradation of RFID system due to curving in tag antenna: assessment and solutions

We have analyzed the main cause of performance degradation in the maximum readable distance due to curving of the tag antenna for passive RFID system at UHF band. We concluded that the variation in impedance was the main reason for such degradation. Such observation was verified by a new design of tag antenna under curved situation. We managed to recover the maximum readable distance to 2m when the tag was bent to 180° with the new design.