Safety assessment of electromagnetic exposure from a 13.56 MHz RF anti-theft device

Radio frequency anti-theft devices employ radio frequency identification (RFID) technology to identify and track objects. An anti-theft system based on the identification of information legitimacy judgment realizes an anti-theft alarm function. In this study, we effectively evaluated the safety of a 13.56 MHz RF anti-theft device in terms of electromagnetic exposure of pedestrians using the RF module in the COMSOL Multiphysics software. To this end, we designed an electromagnetic environment model to study the public electromagnetic exposure of pedestrians when such an RF anti-theft device is used. In particular, four exposure scenarios were analyzed in which the antenna system of the RF antitheft device was operating at 100 mW and 1 W and a pedestrian was located at the center (location A) and 25 cm away in front of the center (location B) of the anti-theft device. The results showed that when the pedestrian was at location A, for the aforementioned antenna feed power of 100 mW and 1 W, the maximum electric field strength of the whole body tissue was 0.26 V/m and 0.84 V/m, and the maximum magnetic field strength was 0.05 A/m and 0.16 A/m, respectively. The maximum values of the specific absorption rate (SAR) were 1.55×10-5 W/kg and 1.5×10-4 W/kg, respectively. When the pedestrian was at location B, for the aforementioned antenna feeding power of 100 mW and 1 W, the maximum electric field strength of the whole body tissue was 0.1 V/m and 0.36 V/m, and the maximum magnetic field strength was 2.08×10-3 A/m and 6.56×10-3 A/m, respectively. In this case, the maximum SAR values were 2.29×10-6 W/kg and 2.92×10-5 W/kg, respectively. These values obtained from simulation are lower than the public electromagnetic exposure limit established by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). This indicates that pedestrians passing through the RF electromagnetic environment analyzed in this study are within a safe range of public electromagnetic exposure. Therefore, the proposed anti-theft device does not pose a threat to public health.