Performance assessment of an enhanced RFID sensor tag for long-run sensing applications

In this paper we present a battery-less RFID sensor tag, operating at 868 MHz, characterized by a novel impedance matching, guaranteeing improvements in terms of wireless energy transfer efficiency. A more efficient energy transfer is of high interest for several applications and, in particular, for a reduced recharging time of the embedded capacitor. This represents a fundamental step to enlarge the range of applications usually limited to classic wireless sensor networks, such as data logging or environmental sensing in large spaces. Challenges related to energy replenishment and data collection should be taken into account to enable an effective deployment of large networks. In particular, we investigate on the number of mobile readers moving around a sensing network to gather data and transfer energy, such that all nodes are kept alive and all data is collected. The improvements introduced by the new RFID sensor tag for this application will be evaluated with respect to state-of-the-art devices.