Characterizing Radio Frequency Transmission and Attenuation in Underwater Wireless Communication

Underwater EM-RF communication poses a significant challenge due to the distinctive properties of seawater. These properties include Propagation speed, Attenuation, Frequency-Dependence Absorption, Conductivity, Dielectric constant etc. The seawater is saline in nature and because of its salinity, it exhibits these properties leading to the absorption of the EM waves, especially RF waves. RF waves are rapidly attenuated in seawater due to conductivity, permeability, and permittivity, understanding these characteristics of electromagnetic wave propagation in seawater is crucial. The frequency variation of seawater's permittivity controls these characteristics. Our model shows the Extremely Low Frequency band can travel long distance in seawater with low attenuation but it requires large antennas and high power to transmit these ELF bands. Temperature, frequency and salinity changes with depth in the presence of EM wave. This demonstrates a drastic decrease in the attenuation of RF wave in deep water compared to shallow water, particularly for high Frequency up to 1THz. The calculations made in this paper is mainly dominated by Debye Polar Molecules.