# Analyzing the SAR in Human Head Tissues under Different Exposure Scenarios
## 3 Results and Discussion
### Limitations and Further Studies  
The results provided here pertain solely to the SAR analysis conducted at 900/1800 MHz frequencies and specific head tissues (such as the brain, muscles, and fat) using human models representing babies, children, adult females, and adult males. With the help of the method proposed in the study, SAR values can be calculated at different frequencies for  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Ref.** & **Year** & **Frequency (MHz)** & **Different Ages** & **Different Tissues** & **Results** \\ \hline \multirow{2}{*}{[11]} & \multirow{2}{*}{2004} & \multirow{2}{*}{900, 1800} & \multirow{2}{*}{Yes} & \multirow{2}{*}{Yes} & The peak SAR decreases with decreasing head size but percentage of the energy absorbed in the brain increases. \\ \hline \multirow{2}{*}{[13]} & \multirow{2}{*}{2008} & \multirow{2}{*}{900, 1800, 2100, 2400} & \multirow{2}{*}{Yes} & The maximum SAR 10g in the head models of the adults and children are almost the same, while SAR of brain tissues of child models is higher than that it adults. \\ \hline \multirow{2}{*}{[17]} & \multirow{2}{*}{2008} & \multirow{2}{*}{20 to 2400} & \multirow{2}{*}{Yes} & The standard deviation of whole-body averaged SAR of adult models can reach 40\%, which proves the variability of adult models. Additionally, the whole-body average SAR of children is over the relevant limits. \\ \hline \multirow{2}{*}{[12]} & \multirow{2}{*}{2010} & \multirow{2}{*}{900, 1800} & \multirow{2}{*}{Yes} & Age dependences of dielectric tissue properties do not lead to systematic changes of the peak spatial. However, major age-dependent changes were observed for the exposure of particular tissues. \\ \hline \multirow{2}{*}{[24]} & \multirow{2}{*}{2019} & \multirow{2}{*}{850, 900, 2100, 2600, 5100} & \multirow{2}{*}{No} & \multirow{2}{*}{Yes} & Regardless of the frequency, if the antenna radiated power is low, temperature increase within the human tissues is low, and hence the SAR. However with the increase in radiated power, SAR also increases, and in the same cases, exceeds the limit in all head tissues. \\ \hline \multirow{2}{*}{[19]} & \multirow{2}{*}{2020} & \multirow{2}{*}{900, 2100, 2450, 2600} & \multirow{2}{*}{Yes} & \multirow{2}{*}{No} & Based on the near-field exposure results, the SAR values vary for the antenna type and pregnant model type, and for some scenarios the SAR values are not within the limits. \\ \hline \multirow{2}{*}{[15]} & \multirow{2}{*}{2021} & \multirow{2}{*}{800, 900, 1800, 2100} & \multirow{2}{*}{Yes} & \multirow{2}{*}{Yes} & Adolescents experience higher modeled RF doses in the whole-brain compared with children, while children are exposed to higher RF doses in the whole body. \\ \hline \multirow{2}{*}{This Study} & \multirow{2}{*}{2023} & \multirow{2}{*}{900, 1800} & \multirow{2}{*}{Yes} & \multirow{2}{*}{Yes} & Frequency, radiated power, gender, age, and tissue type each have an effect on induced SAR levels. Local SAR values exceed the limits under some exposure scenarios. \\ \hline \hline \end{tabular}
\end{table}
Table 6: Comparison of this work with existing studies.  
different morphology and parts/tissues of the body. Therefore, comparisons with limits of exposure and recommendations for acceptable SAR limits which takes age (baby, children) into account can be made.