Statistical Evaluation of the Coupling Effects between Tags in a UHF RFID Forward Link
Résumé
The aim of this paper is to propose a statistical analysis of the performance of an RFID system in a high-density context, based on a physical model which takes into account the mutual coupling and random position of tags. The read-range of an isolated tag is measured and validated from simulation. The degradation in terms of read-range and the power absorbed by the RFID chip is analysed in the presence of surrounded short-circuited tags. Then a set of randomly distributed RFID tags are modelled by a set of loaded half-wave dipoles distributed over an electrically small area to observe the absorbed power on circuit-level. An impedance matching technique employing a T-match has been adapted with dipoles for maximum power transfer in the forward link. The coupling effects taking into account the randomness of dipoles are studied using linear and circular polarisations of the incident field. Numerical Electromagnetics Code (NEC) simulator and High-Frequency Structure Simulator (HFSS) are used for the assessment of forward links for dipoles (with and without T-match) and tags respectively.
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