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RFID tags are used everywhere, from passports to prepaid cards to inventories. In this talk, first the various uses of RFID tags will be discussed in brief, pointing out the key-technologies and their respective pros and cons. The main reasons hindering the wide spread deployment of passive RFID tags are high cost and limited range. The present talk will focus on developing a sub-cent RFID capable of operating from a reasonable distance, though with some compromise on the information content. The resonance behavior of backscatter from a metal patch on a metallic ground plane, separated by a dielectric, could be used as an information storing tag. The dimensions of such a tag define the poles and zeros shaping the scattered signal. By analyzing the scattered signal, the resonating frequency could be assessed. In this talk, we will discuss the possibility of using such a passive tag as a information storing device and the problems of correctly retrieving the information. The limitation of the information content could be addressed using multiple patches, either stacked on top of each other, or located transversely. Since there are ample applications of read-only RFID with limited information content, the present technology is expected to fill a substantial part of the niche of sub-cent tags.

The challenge is to retrieve the resonant frequencies - from single or multiple patches - in the presence of clutter (unwanted scatter) from surrounding objects. The situation becomes especially difficult in the presence of large metallic objects creating significant amounts of clutter. We have proposed ways to separate resonating part of the signal from clutter, following which soft-computing technique is used to find exact resonating frequency. Multilayer Perceptron trained with error back propagation is used to make very accurate estimation of the resonant frequencies in real-time. Experimental results and possibilities of real World deployment will be discussed.


Goutam Chakraborty received his Ph.D. in 1993 from Tohoku University, Japan. Presently he is Professor and head of the Intelligent Informatics lab., Department of the Software and Information Science, Iwate Prefectural University, Japan. His main research interests are Soft Computing algorithms and their applications to solve pattern recognition, data-mining, signal analysis, prediction, scheduling and optimization including applications in wired and wireless Networking problems.