Non-Linear Effects in UHF RFID Technology

The UHF RFID technology has been used, since more than two decades, to identify items remotely using radiofrequency waves.The RFID tag is able to harvest the incoming power from the reader and to modulate the backscattered wave to encode information.Thanks to this architecture, these tags can be completely passive.Finally, their cost can be as low as 0.3 per tag.Since all UHF RFID tags include a harvester (or an envelope detector), all tags can also be considered as non-linear transponders.This paper discusses the classical non-linear effects (harmonic and inter-modulation) which can be exploited to enhance the functionality of the technology and/or improve its performance.Finally, note that these non-linear effects and the generated harmonics are not yet exploited by classical RFID readers.