Automatic IR UWB chipless RFID system for short range applications

The decoding of ultra-wide band (UWB) chipless radio frequency identification (RFID) tags is often performed extracting its frequency response, by removing the channel contribution. In this paper, an automatic short range (<; 50 cm) ultra-wide band (UWB) impulse radio (IR) chipless (RFID) system is proposed. The system is composed of four different coded 5-bits UWB chipless RFID tags fabricated by printing silver ink on a polyethylene terephthalate (PET) substrate, and an impulse radio (IR) UWB radar available commercially. A novel decoding algorithm is implemented to scan the interrogation zone, detect when an UWB chipless RFID tag is placed, and then proceed to identify it without the need of a reference or channel measurement in a line-of-sight, multipath free scenario. The decoding is based on a maximum likelihood (ML) rule to estimate the received UWB chipless RFID tag code embedded in the backscattered pulse. The different UWB chipless RFID tags are successfully decoded automatically, verifying the viability of this methodology.