Electric and electromagnetic coupled sensor components for passive RFID

This work discuss the possibilities of integrating passive sensor components to passive UHF RFID tags. The sensor system works by degrading a tag´s communication performance in proportion to a sensed quantity. Two approaches are studied, sensors directly integrated to tag antenna structures and sensors electromagnetically coupled to tag antennas. The em coupled sensors provide the possibility to produce small sensor components as easily applied add-ons to ordinary commercial RFID tags.