Dual-mode RFID tag antenna on flexible silk

This paper presents a miniaturized implantable RFID tag antenna wrapped in flexible silk and applied in 920–928 MHz Industrial, Scientific, and Medical (ISM) band. A meandered tag antenna geometry is fed by a nested slot, where an RFID tag chip lies. The purpose of usage of flexible silk material is not only to avoid injection when being implanted (under-skin mode), but also to conduct another working mode, i.e. sticking to human body (on-skin mode). The band width of under-skin working mode is 280 MHz at 913 MHz, while reflection parameter is below −13.5 dB within ISM band in on-skin working mode. Finally, the antenna matching performance is verified by adding a body-tissue phantom into simulation.