# Electromagnetic Assessment of UHF-RFID Devices in Healthcare Environment
## 3 Results
### Specific Absorption Rate (SAR) Values from Exposure near Handheld UHF-RFID Readers  
Considering the exposure to EMF of the user of the MO-RFID reader, the highest WB SAR value (0.036 W/kg, i.e., approximately to 50% of relevant limit regarding the exposure of general public, as set by the European recommendation 519/1999) was obtained at the AU and BU exposure scenarios, when a MO-RFID reader is grasped near the front of the body. The obtained SAR values were summarized in Table 8.  
Considering the exposure of the other person present nearby the activated reader (scanned person or anyone present in the vicinity), the highest WB SAR value (0.034 W/kg, \begin{table}
\begin{tabular}{c c c c} \hline \hline  & \multicolumn{3}{c}{**Calculated E-Field, Ec, V/m**} \\ \hline
**Azimuth, (o)** & \begin{tabular}{c} **3 m Away from the** \\ **Reader** \\ \end{tabular} & \
\begin{tabular}{c} **1 m Away from the** \\ **Reader** \\ \end{tabular} &
\begin{tabular}{c} **0.5 m Away from the** \\ **Reader** \\ \end{tabular} \\ \hline
0 & 2.65 & 7.94 & 15.88 \\
45 & 1.78 & 5.34 & 10.68 \\
90 & 0.51 & 1.52 & 3.05 \\
135 & 0.44 & 1.33 & 2.65 \\
182 & 0.39 & 1.17 & 2.33 \\
225 & 0.32 & 0.96 & 1.91 \\
270 & 0.69 & 2.06 & 4.11 \\
315 & 20.3 & 6.08 & 12.16 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: The E-field peak values measured at 0.5 m, 1.0 m and 3.0 m from the AG-RFID reader [13]. Figure 9: Spatial distribution of E-field calculated near AG-RFID reader [13]. again approximately to 50% of the limit on public exposure) was obtained at the CP exposure scenario, when MO-RFID reader is in front of the chest. The maximum values of local SAR 10g were obtained for the palm of MO-RFID reader operator (in the AU scenario), as well as the breast and head of the exposed person (in the CP and FP scenarios)--at the levels comparable with a relevant limit regarding the exposure of general public. Local SAR 10g values in other analyzed cases (in legs, torso and head) were found significantly lower due to significantly greater distance between the reader antenna and the particular parts of the body. Figure 10 shows the E-field distribution within the UHF-RFID gun area, at a radiated power of 1 W: distribution along the plane normal to the antenna. The reading range of various UHF-RFID reader depends upon the radiated power and sensitivities of a passive tag used (typically 0.6-1 V/m of EMF exposure coming from the reader is required to read passive tags, however older tags may have lower sensitivities) [12]. The passive tags reading range of such sensitivities at a radiated power of 1 W was found in the range 4-10 m. The E-field values lower than 3 V/m (minimum required electromagnetic immunity of medical equipment used in professional healthcare environment according EN 60601-1-2) in this case were found at distances longer than approximately 30% of the reading range [35]. The worst-case may be depicted as a stay near a reader for 6 min with continuous emission at maximum power, although a more usual exposure scenario is with a shorter exposure time. Moreover, the remaining furniture, its fixation, the gun handle and the  
Figure 10: E-field distribution at a plane normal to the UHF-RFID gun antenna plane at a radiated power of 1 W. Spatial distribution of E-field measured near the AS-RFID reader. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Exposure** & \multicolumn{2}{c}{**WB**} & \multicolumn{3}{c}{**NSAR 10g**} \\
**Scenario** & **NSAR** & & & & & \\ \hline  & & **Head** & **Torso** & **Palm** & **Arm** & **Leg** \\ \hline AU–Head-20 cm & 0.036 & 0.091 & 0.038 & 4.2 & - & 0.0026 \\ BU–Chest-20 cm & 0.036 & 0.054 & 0.34 & 3.8 & - & 0.0079 \\ CP–Hip-16 cm & 0.034 & 0.33 & 2.1 & - & 0.15 & 0.051 \\ DP–Chest-5 cm & 0.014 & 0.095 & 0.82 & - & 2.1 & 0.020 \\ EP–Side-5 cm & 0.022 & 1.3 & 0.46 & - & 0.15 & 0.0021 \\ FP–Chest-5 cm & 0.018 & 2.1 & 0.15 & - & 0.014 & 0.0044 \\ \hline \hline \end{tabular}
\end{table}