Chipless RFID Threshold Temperature Sensor Compliant with UHF and ISM Radio Frequency

A new chipless RFID sensing concept compliant with Ultra High Frequencies (UHF) RFID and Industrial, Scientific and Medical (ISM) frequency bands is proposed. The concept is demonstrated with the design of a chipless threshold temperature sensor based on C-like scatterrers. The variation of the substrate permittivity with the temperature enables the transduction of the temperature into a frequency detuning that is used to encode the temperature thresholds in a binary form.