Using UWB IR radar technology to decode multiple chipless RFID tags

In this paper, a technique to decode multiple ultra-wide band (UWB) chipless radio frequency identification (RFID) tags using UWB impulse radio (IR) radar technology is proposed. The methodology presented is proven for decoding several chipless RFID tags simultaneously placed in the reader's identification zone, and it is based on the analysis of the received pulses backscattered from chipless tags located at the same or different distance from the radar. The decoding takes places using an algorithm that analyzes the backscattered pulses time-difference-of-arrival (TDOA), energy and the chipless tags coding to detect tags-collision scenarios. Several chipless tags having either the same or different code within the UWB frequency range from 4 to 8 GHz are fabricated using aluminum on polyethylene terephthalate (PET) substrate. The technique is validated experimentally using the UWB IR radar principle and technology to perform the decoding of multiple chipless RFID tags simultaneously placed in reader's identification zone. The chipless RFID tags are successfully decoded in eight different combinations scenarios.