Investigation into the properties of the north seawater for radio frequency propagation

Radio frequencies (RF) suffer from absorption and dispersion in seawater due to high conductivity. However, use of RF for underwater communication is viable. RF offers the advantage of low latency and high bandwidth compared to acoustic signals. It is also harmless to marine lives. However, to optimally utilize RF in the seawater, some investigations on the properties of the medium such as permittivity and the loss tangent would have to be performed. These results would be useful in designing, modelling and optimizing an RF antenna for underwater communications targeting the North Sea. Three seawater samples were obtained from Musselburgh, Newhaven and Portobello. Some tests were performed on the samples using the 8753C Network Analyser and 85070E Dielectric Probe Kit. The results obtained were compared with that of Computer Simulation Technology (CST) and Debye’s model. It was shown that the flat value of permittivity for seawater in CST at 74 for all frequencies was impractical. The loss tangent of the experimental and Debye's models were compared. The Debye's model for the North Sea was used to validate the experimental values.