Experimental testbed for seawater channel characterization

Shallow seawaters are problematic for acoustic and optical communications. Sensor networks based on electromagnetic (EM) communications are evaluated in this environment. In order to characterize the underwater channel, several measurement systems have been designed, built and tested in the sea obtaining very reliable results. Experiments carried out with dipoles and loop antennas showed serious disagreement with the state of the art, especially when dipole antennas are used. Dipoles performance was poor while magnetic loops showed much lower attenuation. A measurement system is described in detail and real attenuation of the underwater channel is obtained for several distances and antennas. Finally, measured and simulated results are compared and reveal good agreement.