A Wearable Textile RFID Tag Based on an Eighth-Mode Substrate Integrated Waveguide Cavity

A novel wearable textile Radio Frequency Identification (RFID) tag based on an eighth-mode substrate integrated waveguide cavity is presented. Antenna size reduction for effective operation in the [865-870]-MHz RFID UHF band is obtained by exploiting the H-field symmetry planes of a cylindrical Substrate Integrated Waveguide (SIW) cavity. High isolation from the human body and excellent robustness with respect to variations in antenna-body distance are achieved using an energy-based design strategy, aiming to reduce ground plane size. The resulting tag exhibits very low manufacturing complexity and may be produced at low-cost. Design and simulations were performed using CST Microwave Studio, and a prototype of the tag has been manufactured and tested in a real environment.