An Evaluation of Electromagnetic Exposure While Using Ultra-High Frequency Radiofrequency Identification (UHF RFID) Guns

Abstract

The aim is to evaluate specific absorption rate (SAR) values from exposure near handheld ultra-high frequency radiofrequency identification readers (UHF RFID guns—small electronic devices, or even portable computers with relevant accessories—emitting up to several watts of electromagnetic field (EMF) to search for RFID sensors (tags) attached to marked objects), in order to test the hypothesis that they have an insignificant environmental influence. Simulations of SAR in adult male and female models in seven exposure scenarios (gun near the head, arm, chest, hip/thigh of the operator searching for tags, or near to the chest and arm of the scanned person or a bystander). The results showed EMF exposure compliant with SAR limits for general public exposure (ICNIRP/European Recommendation 1999/519/EC) at emissions up to 1 W (reading range 3.5–11 m, depending on tag sensitivity). In the worst-case scenario, guns with a reading range exceeding 5 m (>2 W emission) may cause an SAR exceeding the general public limits in the palm of the user and the torso of the user, a bystander, or a scanned person; occupational exposure limits may be exceeded when emission >5 W. Users of electronic medical implants and pregnant women should be treated as individuals at particular risk in close proximity to guns, even at emissions of 1 W. Only UHF RFID guns emitting below 1 W may be considered as environmentally insignificant EMF sources.

Evaluation of SAR in Human Body Models Exposed to EMF at 865 MHz Emitted from UHF RFID Fixed Readers Working in the Internet of Things (IoT) System

“…The numerical model of the UHF RFID antenna was validated by comparing the electric field distribution near the reader, obtained by measurements and numerical simulations. Differences below 10% were demonstrated-for more details see [3]. Table 1 shows the results of the numerical simulations of SAR values related to exposure to EMF at 865 MHz near to UHF RFID antennas at an input power to each single antenna of 1 W, analysed with respect to continuous exposure-the worst-case exposure scenario with respect to the exposure duration and the rules of evaluating the thermal load from human exposure to EMF (set to be timeaveraged over six minutes for local SAR averaged over a 10 g mass of any continuous tissue, SAR10g, and over 30 min for SAR averaged over the entire exposed body, WBSAR).…”

“…The modelled EMF source was a rectangular microstrip patch antenna designed to operate at 865 MHz to support the frequency range of UHF RFID applications in Europe. An antenna of dimensions 99.6 × 122.5 mm was placed on substrate and ground layers with dimensions 131.5 × 138.3 mm-for more details see [3]. Copper with a thickness of 0.035 mm, an electric conductivity of 5.813 × 10 7 S/m, and a relative permittivity of 1 was used for the antenna; Rogers RO3003 with a thickness of 1.52 mm, an electric conductivity of 2.2 × 10 −4 S/m, and a relative permittivity of 2.92 was used as substrate; ground with a thickness of 0.035 mm was modelled as the perfect electric conductor (PEC).…”

Modelling and Evaluation of the Absorption of the 866 MHz Electromagnetic Field in Humans Exposed near to Fixed I-RFID Readers Used in Medical RTLS or to Monitor PPE

“…After more than 20 years of continuous development, IoT is now the basic platform on which the concept of Industry 4.0 and health monitoring systems (Healthcare 4.0) are developing [ 3 ]. One of the widely used communication technologies that may be incorporated into the IoT concept is the RadioFrequency IDentification (RFID) system [ 4 , 5 , 6 , 7 , 8 , 9 ]. The combination of these is known as IoT RFID (I-RFID) [ 10 ].…”

“…The complexity of the system and kind of the application determinates the technology, and thus the hardware and software required to develop the best-suited RTLS. One of the most widely used communication technologies that may be incorporated in RTLS is the RFID system [ 4 , 5 , 6 , 7 , 8 , 9 ]. This identification technology uses radio waves (electromagnetic non-ionising radiation) to transmit data and, when required by the use of passive tags, also to wirelessly power an electronic circuit attached to objects covered by the application.…”

“…The maximum reading range (i.e., the maximum distance where tags efficiently communicate with the reader) in systems using UHF RFID passive tags depends on the power emitted from the reader antenna, the tag sensitivity and the conditions of wave propagation [ 4 ]. Typically, it does not exceed 20 m, though the majority of applications operate at a much shorter reading range.…”