A reconfigurable chipless RFID tag based on sympathetic oscillation for liquid-bearing applications

This paper reports on the development of a 10-bit chipless RFID tag on flexible plastic substrate. This tag is based on sympathetic oscillations of a group of LC circuits with different resonant frequencies. Sophisticated designs including the placement of capacitors involved in each LC circuit, and various LC combinations are examined for the trade-off of the readability and the tag sizes. Moreover, the antennas for detecting the proposed tags are presented. The measurement results show that the proposed tag possesses remarkable readability for a read range up to 21 cm and more importantly, it is suited for tagging liquid-bearing containers, which are widely used in food and medical industries. In addition, this tag is reconfigurable on circuit level, enabling a potential pathway towards the realization of low cost RFID tags for HF/VHF band applications.