Lifetime extension of semi-passive UHF RFID tags using special power management techniques and energy harvesting devices

Nowadays requirements on RFID systems are going beyond simple identification of objects; sensing and monitoring and thus autonomous operation, large memory areas in combination with high computational capabilities as well as high operating ranges are needed. This requires a revision of the formerly passive tag architecture adding various functional blocks and the most significant change of adding an energy reservoir to the formerly pure passive operating tags. As a key parameter of the reliability of an RFID system is the lifetime, a key topic for the development of enhanced tag architectures is the power management mechanism. It includes to operate the tag with the lowest possible energy, but even to ensure to keep its energy budget as balanced as possible. The PowerTag(1) project and thus this paper deals with proposing special power saving mechanisms in combination with the use of energy harvesting devices to harvest power from the environment for the support of the on board battery.