Path Loss From a Transmitter Inside an Aircraft Cabin to an Exterior Fuselage-Mounted Antenna

The increasing use of mobile electronic devices by passengers and equipment on large aircraft may increase the likelihood of interference with the aircraft´s electronic systems. Thus, the “interference path loss” from a transmitting device inside the cabin of such aircraft to the antenna terminals of a victim system of the aircraft is of interest. Full-wave modeling and other deterministic techniques are impractical or undesirable for this purpose due to the potentially large electrical dimensions of the aircraft, as well as the variability of the cabin configuration. An alternative hybrid analysis technique applicable to frequencies above very high frequency is proposed in which one first estimates the power that escapes the cabin using a simple method based on microwave cavity theory. Next, the radiating windows are modeled as magnetic currents on a cylinder modeling the fuselage, and the resulting electric field at the location of the victim antenna is determined using the uniform geometrical theory of diffraction. Finally, the power delivered to the victim antenna is estimated as the coherent sum of fields incident from the windows. This technique yields results consistent with measured results and yields additional physical insight that would be difficult to obtain through measurements or full-wave methods.