Passive UHF RFID transponders for switching and controlling

Abstract

Simple UHF RFID sensors allow the wireless control of electrical and mechanical states like the position of an object or a mechanical component. An RFID chip combined with an antenna and a transmission line builds a simple sensor module. For many applications it is sufficient to discover whether the RFID transponder can be activated or not. A status transition may change the reaction of the transponder depending on the length of the transmission line and its loading. A second approach allows measuring the exact position of a tagged object along a line. User benefits of the RFID technology are its high sensitivity for activation and the possibility to spatially separate the transmission and measurement locations. This offers a new economic all-purpose opportunity for object monitoring and state control without any power consumption.