## 5 Conclusions  
The paper highlights the characteristics of the channel and possible effects over the EM frequencies, specifically over the 2.4 GHz ISM frequency band. After the deliberation of EM properties of the medium, we tested 2.4 GHz in freshwater and estimated the path loss. It is concluded that path loss inside fresh water at 2.4 GHz is 1.6 times greater than the path loss in the terrestrial indoor environment using the same frequency. Furthermore, from the results of velocity of propagation of 2.4 GHz in underwater, it is concluded that velocity of EM decreases as water quality degrades. Propagation of the speed of sound underwater is 1500 m/s; however, sound waves cause a significant delay in the overall transmission. EM waves are faster than acoustics even underwater, thus, EM waves can be considered real-time applications. In addition, from the results of absorption losses for 2.4 GHz when simulated underwater at different medium conductivities, it is concluded that the absorption losses increase as water conductivity increases. Specifically, absorption losses are about 9 dB to 19 dB in freshwater conductivity at 2.4 GHz, the absorption losses are about 19 dB to 24 dB in river water conductivity at 2.4 GHz, and absorption losses are about 25 dB to 30 dB in seawater at 2.4 GHz.  
Moreover, we verified a subset of frequencies for which the absorption losses are less than 3 dB for different water conductivities. Therefore, for absorption losses less than 3 dB at water conductivity of 0.001 S, the radios ranging from \(1\times 10^{8}\) Hz or greater can be used. Similarly, for absorption losses less than 3 dB at water conductivity of 0.01 S, the radios ranging from \(1\times 10^{7}\) Hz or greater can be used. In addition, for absorption losses less than 3 dB at water conductivity of 0.001 S, the radios ranging from \(1\times 10^{6}\) Hz or greater can be used. Thus, this paper proposes EM waves for UWSNs. The results presented in this paper highlight the significance of EM waves for UW communications. EM waves have significance when considering shallow water communication and real-time applications. There are many RF frequencies that give less attenuation in certain conditions. In fresh and river water conditions, EM out performs acoustics in terms of bandwidth.  
Figure 10: Absorption loss for MHz frequency (radios) at different conductivities of water.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Conductivity Values (\(\delta\))** & **Frequency Ranges (Hz)** & **Estimated Losses (dB)** \\ \hline
0.001 S & \(10^{8}\) & 2.98 \\
0.01 S & \(10^{7}\) & 2.98 \\
0.1 S & \(10^{8}\) & 2.98 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Absorption Losses for MHz Radios at Different Conductivities of Water.  
**Acknowledgments:** This work is supported by the National Science, Technology and Innovation Plan (NSTIP), strategic technologies program number 11-INF1688-10, King Abdul Aziz City of Science and Technology, Kingdom of Saudi Arabia. We also thank the Science and Technology Unit for their logistic support.  
**Author Contributions:** All authors contributed equally to this work.  
**Conflicts of Interest:** The authors declare no conflict of interest.