RFID READING METHOD AND RFID READER

A radio frequency identification (RFID) reader sequentially carries out inventory rounds with passive RFID sensor tags. Each RFID sensor tag has at least one sensing element arranged to sense a predetermined quantity. The RFID reader reads one value of the predetermined quantity based on a backscattering modulation frequency used by the passive RFID sensor tag during each inventory round and releases the RFID sensor tag prior to reading next value of the predetermined quantity based on a backscattering modulation frequency used by the passive RFID sensor tag during a subsequent inventory round. If the passive RFID sensor comprises two or more sensing elements having different sensor characteristics, the RFID reader reads one of the sensing elements of the passive RFID tag during one inventory round and releases the passive RFID sensor tag prior to reading another one of the sensing elements of the passive RFID sensor tag during a subsequent inventory round.