Modified open stub multi-resonator based chipless RFID tag

A planar, fully printable, frequency signature based multi-resonator circuit for chipless RFID transponder system and swipe card is presented. The amplitude and/or group delay of the spectral signature are utilized for the chipless tag or swipe card multi-resonator circuit, providing a 1:1 correspondence of data bits. It comprises of a bifurcated microstrip transmission line meeting at the far end within which the open circuited shunt stub multiresonators are positioned. The developed structure can be used effectively as a swipe card. The application of the proposed circuit together with its cross-polarized transmitting and receiving microstrip ultra-wideband disc loaded monopole antennas for RFID transponder system is also presented. The experimental and simulated results in support of the potentials of the chipless tag for low cost item tagging such as bank notes and secured documents are explained in this paper. The circuit is having high quality factor and has a very small footprint of 24×10mm².