Design of phase coded spiral resonator based Chipless RFID tag for tracking applications

Abstract

RFID (Radio identification) is a technology which deals with the wireless identification of people and products. This chipless RFID tag design is on research to replace chipped RFID tags, which employs high cost silicon wafer to store unique identification code. The main challenge in the design of chipless RFID tag is how to encode the data without a chip. This challenge is overcome by the use of electromagnetic properties of the resonators, filters etc to encode the data bits. In this work RFID tag is designed based on multiresonators with each resonator representing a data bit. The proposed tag consists of the multiresonating circuit to store information bits and transmitting and receiving UWB antenna for wireless communication with the RFID reader for identification. The multiresonating circuit designed consists of 4-spiral resonators electromagnetically coupled to the microstip coupled line. Each spiral resonates at unique resonating frequency representing the unique data bit. The data encoding is carried out with the help of phase ripples at the resonating frequency of the spirals. Three variations are observed and corresponding 3-logic states (0, 1, 2) are encoded. The designed tag is simulated in Advanced Design System (ADS) using RO-4003 substrate with the dielectric constant 3.38 and thickness of 20 mil. From the proposed methodology, a total of 34=81 unique tags can be designed that can be employed in cheap item tracking. The Monopole disc antenna is designed which operates for wide band covering all resonating frequency of the spiral resonator.