Exploitation of harmonic signals generated by the UHF RFID chips: New promises for the radio frequency identification technology

The Ultra High Frequencies (UHF) Radio Frequency Identification (RFID) chips generate harmonic signals due to their nonlinear circuits. Usually these harmonic signals are seen as harmful because they are considered as efficiency losses or potential sources of disturbing signals. This paper overviews several recent works demonstrating that the harmonic signals produced by the UHF RFID chips could be source of new capabilities for the tags.