On-body Read Range Enhancement of Commercial UHF RFID Tag with Split Ring Resonator (SRR)

Commercial Ultra High Frequency Radio Frequency Identification (UHF RFID) tag has been incorporated with Split Ring Resonator (SRR) for on-body application. However, an external structure with permittivity approximately similar to the air, vacuum or free space for further decoupling of the human body from the tag incorporated with SRR is required. Consequently, a low profile and seamless integration of the tag incorporated with SRR is failed to achieve. Therefore, in this study, the SRR was incorporated with the commercial UHF RFID tag on the same plane as the tag antenna. The proposed design achieved a simulated on-body read range of 1.1 m in body-worn configuration. This is achieved by the incorporation of SRR that decreases the real part of tag antenna’s impedance by 37%. Thus, it is noteworthy that the coplanar SRR on the tag antenna is able to enhance the read range for on-body application, hence, contributing to a low-profile tag for wearables.