Chipless RFID Readers for Frequency-Coded Tags: Time-Domain or Frequency-Domain?

Printable ultra-wideband (UWB) frequency-coded chipless radio frequency identification (RFID) tags are suitable candidates for barcode replacement toward developing smart objects. A high-performance and low-cost UWB chipless RFID reader is needed to interrogate UWB frequency-coded tags. Time-domain and frequency-domain techniques are the most popular approaches employed in readers to extract the tag information. This paper reviews the state-of-the-art frequency- and time-domain chipless RFID readers for reading frequency-coded tags. A comprehensive study on the main challenges in designing a sound reader such as detection range, immunity to the interferences, detection speed and accuracy, cost, reader profile, and compatibility with hybrid tags is conducted. Finally, a new reader architecture for reading hybrid tags to achieve higher data capacity is presented. The reader is capable of detecting a chiplesstag independent of its orientation and has considerable potential for commercial realization.