Affiliation: Iwate Prefectural University, Japan
Title: A Novel Realization of Chipless RFID
In recent years RFID tags are used everywhere, from passports to prepaid cards to inventories. Possibility of wider deployment is hindered due to high cost and limited range of operation. 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. Such a truly passive tag has the potential for a longer range than ones using semiconductor chips, the latter ones being range-limited due to the minimum power requirement for the chip. The chipless ones are inherently low information content compared to the semiconductor-based ones, but there are ample applications of read-only RFID with limited information content that the present approach could offer for sub-cent deployment. Moreover, use of multiple patches could potentially increase information content if required. The challenge is to retrieve the resonant frequencies from the backscatter in presence of clutter (unwanted scatter from surrounding objects). In addition, different frequency components of the incident signal undergoes different phase shifts due to path-delay between transmit and receive antennas, and corrupt the phase shift variation in the resonance regions. We propose a pre-processing technique to remove this path-delay effect as well as selection and cropping of the part of the signal relevant to resonance. We created synthetic supervised data to train an artificial neural network (ANN) using error-backpropagation. Once the resonance part of the signal is fed to it, it outputs the resonating frequency, i.e., the information stored in the tag. The ANN is trained with synthetic data in such a way that the result is robust to marginal error in estimating the resonant frequency. Various experimental results are included in the talk to show the effectiveness of the technology proposed.
Goutam Chakraborty is a Professor and Head of the Intelligent Informatics Laboratory, Department of the Software and Information Science, Iwate Prefectural University, Takizawa, Japan. His main research interests are soft computing algorithms and their applications to solve pattern recognition, prediction, scheduling and optimization problems including applications in wired and wireless networking problems.