## 2 Materials and Methods
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Subbands** & **f\({}_{lower}\) (MHz)** & **f\({}_{upper}\) (MHz)** & **f\({}_{r}\)** \\ \hline LTE 800 & 791 & 820.9 & 805.95 \\ \hline ETC 1 & 821 & 925 & 873 \\ \hline LTE 900 & 925.1 & 935 & 930.05 \\ \hline GSM 900 & 935.1 & 961 & 948.05 \\ \hline ETC 2 & 961.1 & 1805 & 1383.05 \\ \hline GSM 1800 & 1805.1 & 1820 & 1812.55 \\ \hline LTE 1800 & 1820 & 1879 & 1849.5 \\ \hline DECT & 1880 & 1899 & 1889.5 \\ \hline ETC 3 & 1900 & 2010 & 1955 \\ \hline UMTS 2100 & 2011 & 2170 & 2090.5 \\ \hline ETC 4 & 2171 & 2399 & 2285 \\ \hline WLAN & 2400 & 2483 & 2441.5 \\ \hline ETC 5 & 2484 & 2569 & 2526.5 \\ \hline LTE 2600 & 2570 & 2670 & 2620 \\ \hline ETC 6 & 2671 & 3000 & 2835.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Division of broadband into 15 subbands and frequency range. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Subbands (\(\mathbf{f_{r}}\) (MHz))** & & **Skin** & **Fat** & **Bone** & **Dura** & **CSF** & **Brain** \\ \hline \multirow{2}{*}{LTE 800 (805.95)} & \(\varepsilon_{r}\) & 41.66 & 5.47 & 12.51 & 44.55 & 68.85 & 46.04 \\ \cline{2-8}  & \(\sigma\) & 0.83 & 0.04 & 0.12 & 0.92 & 2.35 & 0.73 \\ \hline \multirow{2}{*}{ETC1 (873)} & \(\varepsilon_{r}\) & 41.44 & 5.46 & 12.46 & 44.42 & 68.72 & 45.84 \\ \cline{2-8}  & \(\sigma\) & 0.84 & 0.04 & 0.12 & 0.93 & 2.36 & 0.73 \\ \hline \multirow{2}{*}{GSM 900 (948.05)} & \(\varepsilon_{r}\) & 41.26 & 5.45 & 12.41 & 44.31 & 68.61 & 45.67 \\ \cline{2-8}  & \(\sigma\) & 0.88 & 0.05 & 0.14 & 0.97 & 2.43 & 0.79 \\ \hline \multirow{2}{*}{ETC 2 (1383.05)} & \(\varepsilon_{r}\) & 40.05 & 5.39 & 12.10 & 43.59 & 67.89 & 44.56 \\ \cline{2-8}  & \(\sigma\) & 1.03 & 0.06 & 0.21 & 1.15 & 2.68 & 0.97 \\ \hline \multirow{2}{*}{LTE 1800 (1849.5)} & \(\varepsilon_{r}\) & 38.83 & 5.33 & 11.76 & 42.83 & 67.12 & 43.42 \\ \cline{2-8}  & \(\sigma\) & 1.20 & 0.07 & 0.28 & 1.34 & 2.96 & 1.17 \\ \hline \multirow{2}{*}{WLAN (2441.5)} & \(\varepsilon_{r}\) & 38.04 & 5.28 & 11.38 & 42.04 & 66.23 & 42.53 \\ \cline{2-8}  & \(\sigma\) & 1.45 & 0.10 & 0.39 & 1.66 & 3.44 & 1.50 \\ \hline \(\rho\) (density) (kg/m\({}^{3}\)) & \multicolumn{2}{c}{1100} & 920 & 1850 & 1050 & 1060 & 1030 \\ \hline \end{tabular}
\end{table} 
Table 2: Electrical properties of the layers forming the head model according to the six sublayer frequencies. Limits for SAR values are determined between 10 kHz and 10 GHz, taking as reference the 1 g and 10 g tissues of the exposed organ or the whole body. In this regard, while 1 g of tissue is taken as reference in the FCC, 10 g of tissue is taken as reference in the CE, and limit values have been determined for the working environment and public areas, as shown in Table 3.  
To calculate the SAR values in the brain, all electrical components of the six-layer head model angular frequency (rad/s), permittivity (F/m), propagation constant, impedance of the medium (\(\Omega\)), reflection coefficient, and transmission coefficient (\(W,\tilde{e},\hat{\gamma},\hat{\eta},\hat{I}^{\prime}\) and \(\hat{T}\)) are found using the following Equations (3)-(8). \[W=2\pi f_{r} \tag{3}\]  
Figure 4: Head model created for SAR calculation [30]. \begin{table}
\begin{tabular}{c c c c} \hline  & **Whole-Body** & **Localized SAR** & **Localized SAR** \\  & **Average SAR** & **(Head and Trunk)** & **(Limbs)** \\  & **(W/kg)** & **(W/kg)** & **(W/kg)** \\ \hline FCC (1 g) & & & \\ \hline Occupational Exposure & 0.4 & 8 & 20 \\ \hline General Public Exposure & 0.08 & 1.6 & 4 \\ \hline CE (10 g) & & & \\ \hline Occupational Exposure & 0.4 & 10 & 20 \\ \hline General Public Exposure & 0.08 & 2 & 4 \\ \hline \end{tabular}
\end{table} 
Table 3: Electrical properties of the layers forming.