Long reading range chipless RFID system based on reflectarray antennas

This work proposes the utilization of the Reflect Array (RA) antenna in the reader of the Frequency Coded (FC) chipless RFID systems aiming at increasing the reading range, minimizing the environmental reflections and acquiring a lot of novel capabilities that can not be provided by the conventional antenna systems. The FC chipless RFID system requires an UWB range of frequencies to accommodate multiple bits. However, this UWB operation can not be provided by the conventional antenna arrays. Even though, the RA antenna is also suffering from bandwidth limitation, an UWB RA antenna dedicated to the chipless RFID readers is accomplished. The presented RA antenna operates over UWB range of frequencies from 4 to 6 GHz fulfilling the requirements of the FC chipless RFID systems. Furthermore, the RA antenna beam is 4 times narrower than the feeder beam and thus 6 dB higher in gain with -10 dB SLL. Therefore, this developed UWB RA antenna is successfully integrated with the FC chipless RFID tags and a reading range of 1 m is attained. To the best of the author knowledge, this is the highest reading range achieved in the FC chipless RFID systems, considering real-world indoor environment and Universal Software Defined Radio Platform (USRP).