Chipless RFID is a relatively new and rapidly growing field that faces some practical implementation challenges. One of these challenges is extreme sensitivity to small misalignments between the tag and the reader antenna. These tilts and translations can lead to erroneous responses which can then be interpreted as incorrect IDs or sensing parameter values in identification and sensing applications, respectively. While there has been some work to mitigate this limitation through reading and post-processing methods, the problem has yet to be sufficiently addressed from the tag design perspective. This work proposes a misalignment-tolerant chipless RFID tag design methodology that utilizes trihedral corner reflector bases loaded with resonators to produce tags that are tolerant of pitch and yaw rotations up to ±40° and roll rotations up to ±180° (i.e., orientation independence as it is commonly defined in the chipless RFID field). This approach allows for linearly polarized monostatic reading schemes to be used and provides for a large radar cross-section and resonance depth, which increases the detectability of the tag response.
Keywords: Chipless RFID; corner reflector; misalignment tolerant.