Temperature sensor based on frequency-coded chipless RFID tags.

ABSTRACT In this article, the integration of a frequency-coded radio frequency identification tag with an integrated temperature sensor long lifetime is proposed. It is demonstrated that temperature range can be measured and coded in a tag using tunable stub-loaded dual-band resonator that is connected between two orthogonal wideband antennas. The sensor tag emits two different frequencies: the first resonance is used for identification of sensor tag whereas the second frequency is equivalent to temperature. The second resonance is tuned with a varactor controlled by a negative temperature coefficient sensor and its low-power consumption conditioning circuit. The conditioning circuit modifies the voltage of the varactor and this modifies the second resonant frequency. The resonant structure is studied as a proof of concept. Experimental results at different distances are provided. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2411-2415, 2014 [ABSTRACT FROM AUTHOR]