Characterization of RF Propagation in Muscle Tissue for Passive UHF RFID Tags
ABSTRACT In this paper, we present an analytical analysis and study of the propagation of radio frequency (RF) energy in muscle tissue. The workings of passive UHF RFID tag backscatter are studied. Backscatter field strength propagation models are used to describe the skin effect on muscle tissues. Energy dissipation and field intensities are studied for humans and larger vertebrates using a modified Friis propagation model for passive tag backscatter. An analytical evaluation is conducted for the electric field in muscle tissues for near-field distances. It is shown that the maximum electric field inside a sphere of muscle tissue for a typical passive UHF RFID tag with a loaded meander tag antenna is less than 70dBV/m, which is more than two orders of magnitude lesser than the limits for safe exposure to RF energy produced by mobile devices, as adopted by the Federal Communications Commission (FCC).
Full-textDOI: · Available from: Daniel Engels, Dec 14, 2013
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ABSTRACT: This paper presents a fully integrated remotely powered and addressable radio frequency identification (RFID) transponder working at 2.45 GHz. The achieved operating range at 4 W effective isotropically radiated power (EIRP) base-station transmit power is 12 m. The integrated circuit (IC) is implemented in a 0.5 μm silicon-on-sapphire technology. A state-of-the-art rectifier design achieving 37% of global efficiency is embedded to supply energy to the transponder. The necessary input power to operate the transponder is about 2.7 μW. Reader to transponder communication is obtained using on-off keying (OOK) modulation while transponder to reader communication is ensured using the amplitude shift keying (ASK) backscattering modulation technique. Inductive matching between the antenna and the transponder IC is used to further optimize the operating range.IEEE Journal of Solid-State Circuits 12/2005; DOI:10.1109/JSSC.2005.857352 · 3.11 Impact Factor
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ABSTRACT: This paper presents a method for measuring signal backscattering from RFID tags, and for calculating a tag's radar cross section (RCS). We derive a theoretical formula for the RCS of an RFID tag with a minimum-scattering antenna. We describe an experimental measurement technique, which involves using a network analyzer connected to an anechoic chamber with and without the tag. The return loss measured in this way allows us to calculate the backscattered power and to find the tag's RCS. Measurements were performed using an RFID tag operating in the UHF band. To determine whether the tag was turned on, we used an RFID tag tester. The tag's RCS was also calculated theoretically, using electromagnetic simulation software. The theoretical results were found to be in good agreement with experimental dataIEEE Antennas and Propagation Magazine 01/2007; DOI:10.1109/MAP.2006.323323 · 1.15 Impact Factor
- IEEE Transactions on Antennas and Propagation 07/2006; DOI:10.1109/TAP.2006.875934 · 2.46 Impact Factor