Implementation of Sensor RFID: Carrying Sensor Information in the Modulation Frequency

An approach that can be used for exploiting the sensing capabilities of RF identification (RFID) is presented and formulated. In this approach, sensor information is carried through the modulation frequency of RFID. The aim of this work is to investigate the sensor concept and to characterize the sensor performance both theoretically and experimentally. Furthermore, the operation of the sensor RF parts and oscillator are described analytically, and the equations are verified by simulations and measurements. The concept is experimentally demonstrated at a single carrier frequency to test its suitability for ultra-high-frequency RFID applications, and shown to be feasible for implementing sensors that can be read across distances up to 14 m.