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Smart Foil Bag With UHF-RFID Tag Y. S. Yeh , C. H. CHEN * , T. Y. LIN , J. H. Chen , C. H. Chen , Y. S. Li Department of Electro-Optical Engineering,Southern Taiwan University 1 Nan-Tai St., Yung-Kung City, Tainan County, Taiwan, 710 ABSTRACT Radio Frequency Identification (RFID) is a technology which uses RF signals for automatic identification. RFID Tag attached on the product material, product stacking, the environment, may reduce the read range, especially for metallic objects. A slot antenna is easily integrated into metallic objects, so it will be another potential tag antenna type for metallic objects. In the paper, the tags with slot antennas are attached on a foil bag directly. We can largely reduce the cost of RFID tags. Meanwhile, the smart file bag can be identified correctly for a hardware supply chain. I. THEORY r 4 Pr Gt Gr Pth r Pr Gt Gr Pth Read range Power transmitted by the reader Gain of the transmitted antenna Gain of the receiving tag antenna Threshold power of the chip II. EXPERIMENTAL METHOD (a) Network analyzer (b) Carve machine τ τ Power transmission coefficient Zc Impedance of the chip Za Impedance of the tag antenna Rc Resistance of the chip Ra Resistance of the chip 4 Rc Ra Zc Za 2 C. Smart foil bag with UHF-RFID tag (c) CSL reader (b) Tags are placed randomly in the metallic basket (a) The condition of foil bags overlap tag tag tag tag tag (d) The process of smart foil bag (c) Different locations of the slot antenna on the foil bags III. RESULTS AND DISCUSSION A. Simulated impedance of the slot antenna Antenna location Identification rate The slot antenna is located on the center of the bg 13％ The slot antenna is extended to the back of the bag 37％ The slot antenna is located on the side of the bag 93％ Foil bag with two slot-antenna tags 100％ IV. CONCLUSION (a) The length of antenna (La) is 492 millimeter B. Measured impedance of slot antenna on PET substrate In this letter, we propose a smart foil bag with two slot-antenna tags to avoid the reduction of the performance of the tag due to foil bags overlap. The measured results reveal that the input impedance of the slot antenna at difference locations of the bag is independent of locations. Thus, the slot antennas are located on the side of the bag to avoid reducing the performance of the tag owing to the overlap of foil bags. Experimental results show that the identification rate of the tag reaches 100% when the distance between readers is below 100 cm. The authors are also grateful to the National Center for High-Performance Computing (NCHC) for providing computing facilities and technical supports. REFERENCES (b) The measured read range of the tag on PET substrate is about 4-5 meter. (La =160mm) 1. K. V. Seshagiri , Pavel V. Nikitin , Sander F. Lam, “Antenna Design for UHF RFID Tags: A Review and a Practical Application, ” IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 53, NO. 12, DECEMBER 2005. 2. Xuezhi Zeng, Johan Sidén , Gang Wang , and Hans-Erik Nilsson , “Slots in metallic label as RFID tag antenna, ” IEEE ANTENNAS AND PROPAGATION SOCIETY INTERMATIONAL SYMPOSIUM pp.1749–1752, JUNE 2007