Wireless transducer based on split-ring resonator

In this paper we propose a wireless transducer, conceived as part of a wireless sensing tag working on the UHF RFID band. The transducer works both as antenna for wireless communication with a dedicated reader, and as sensing element. It is based on a small loop antenna loaded with a split-ring resonator in a complete single-layer design. Two proof-of-concept prototypes were fabricated, one on FR4 and the other on paper substrates. Both prototypes were easily adapted to work as humidity sensors, and measurements results showed the suitability of the transducer for low-cost wireless sensing applications.