Phase-oriented chemical sensing by passive UHF-RFID

Most of up to day efforts to extract physical information from an object where an RFID tag is attached on are based on the processing of the backscattered power reflected by the tag and collected by the reader. This contribute investigates, for the first time, the use of the phase of the reflected field to derive quantitative information about chemical variations of the environment, nearby the tag. The proposed methodology is described throughout a controlled laboratory experiment involving a chemical doped RFID tag for humidity sensing.