Design of Novel Tag for Epidermal UHF RFID Technology and Sensing Applications

Epidermal RFID technology is currently emerging research, based on epidermal or Skin tag and reader concept. The tag placed at close distance to the skin, thus providing poor communication performances because of the high dielectric properties of skin tissues. Our goal is to design a flexible and thin tag antenna's having high efficiency and matched to the complex impedance of the chip, the substrate of the tag is required to be not only bio-compatible but also breathable, lightweight and stretchable to ensure the preservation of the natural compositions of the skin. This paper presents the design of epidermal dual-loop tag with meandered line, that is based on external rectangular loop with meandered strip, which add the features of stretchability and more reduction of the antenna size, the loop was fed via T match configuration to achieve impedance match between the antenna and the chip, the tuning mechanism was embedded by adding additional strips to the inner loop, that's allow the UHF tag to be useful in all UHF RFID band, the radiator of the antenna is an adhesive copper insulated from the body by single and thin bio-silicone layer (thickness = 0.6mm, epsilon=2.5, sigma = 0.005 S/m). The design of the tag is realized by using a simplified model of the human body, consisting of stratified planar layers of defined thickness. The proposed tag design and simulation results details are presented above by employing the HFSS simulator.