Double directional characterisation of radio wave propagation through metallic watertight doors on board ships

The objective of this Letter is to characterise the electromagnetic wave propagation between adjacent rooms in lower deck areas of ships. A wideband MIMO (Multiple-Input Multiple-Output) channel sounder has been used to realize double directional propagation measurements at 2.2 GHz. The antenna configuration was a linear array at the transmission side and a rectangular one at the reception. The measurement data are first processed with a classic beamforming technique, then with a high resolution algorithm to extract the dominant paths. A ray-tracing based simulation tool is used to understand the measurement results. It is observed that, in spite of the metallic structure of watertight doors, wireless communication remains possible between adjacent rooms after door closure. Results show that electromagnetic waves mainly propagate through door edges openings.