Investigations into improving the detectability of self-resonant RFID tags

This study describes an experimental investigation into improving the detectability of self-resonant structures. Passive self-resonant structures have been used as an alternative to active devices in many applications including radio-frequency identification (RFID) due to their long lifetime and low manufacturing cost. They can be used to store information in terms of the presence or the absence of resonance peaks at a given frequency window. This work investigates practical validation of gain enhancement techniques, aiming to improve the resonance characteristics of passive RFID tags to increase their read range and allow them to operate in highly lossy mediums. Two passive resonator designs are studied: a uniform cross-shaped resonator and a folded (gammadion) cross having a physical aperture 45% less than that of the uniform cross. Arrays of elements have been used to improve the detectability of the structure. Measurement settings have also been investigated in order to achieve higher levels of detectability.