Design of Recognition System for Chipless RFID Tags Based on Spectral Characteristics

Chipless RFID is a good substitute for bar code, for it has longer recognition length, can recognize automatically and it is cheaper and more robust compared with classic RFID tag. Though many types of RFID with different encoding methods were invented, few papers talked about design of a recognition system. To construct a recognition system for chipless RFID tags based on spectral characteristics, this paper concerns to about four parts of the system. When measuring we treat the reflected wave as a periodic signal and let A/D convertors operate one by one to reach a relatively high sampling rate. After that an FPGA based calculation circuit is established to do FFT. After getting the characteristics in frequency filed we establish a deviation correction model to correct scattering parameters. At last, a wave trough detector is design to decode the information.