Increased dynamic range for RFID EM-field measurements

This paper presents a new methodology to measure the electromagnetic (EM) field using RFID tags, overcoming the limitations in dynamic range arisen by the conventional excitation of RFID tags. The methodology consists in the use of two different signals when interrogating the RFID tag. The first signal is in charge of powering up and triggering the response of the RFID tag, while the second one, with lower power, performs the EM-field measurement. With this approach the dynamic range of the EM-field measurement is increased up to the sensitivity of the receiver, and additionally the non-linearities in the measured field distribution are completely removed.