A Passive Long-Range UHF Transponder with Integrated Temperature Sensor

Conference: RFID SysTech 2008 - 4th European Workshop on RFID Systems and Technologies
06/10/2008 - 06/11/2008 at Freiburg, Germany

Proceedings: RFID SysTech 2008

Pages: 4Language: englishTyp: PDF

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Feldengut, Tobias; Wang, Jue; Kolnsberg, Stephan; Kokozinski, Rainer (NN)

Recent development in UHF RFID Tags has been focused on the optimization of the powering and communica-tion range of the reader/tag system. The use of low threshold Shottky-diode rectifiers and the rigorous minimiza-tion of the tag power consumption have yielded read ranges of more than 10 m for simple identification tags. Sensor transponders that serve as nodes in wireless networks require a more complex chip architecture with a stable, regulated supply voltage and precise current- and voltage references. The analog/digital conversion of sensor data leads to short periods of large current consumption on the tag side. A passive UHF sensor tag was designed in a 0.35 µm CMOS process with Schottky diodes and double poly layers. The tag operates in the 868 MHz ISM band and the air interface is compatible to the ISO 18000-6 standard. The analog front-end with temperature sensor consumes 3.5 muA from the DC supply, which leads to an expected range of more than 3 m. The data rate, the size and the maximum range of each sensor node are significantly improved in comparison with existing LF and HF solutions.