In this paper we consider the problem of how to determine path loss from a personal electronic device (PED) radiating in the cabin of a large passenger aircraft to the terminals of a "victim" antenna mounted on the fuselage. The ability to perform such calculations quickly and accurately is important in the analysis of electromagnetic compatibility (EMC) between PEDs and aircraft navigation and communications systems. Solutions for this problem using full-wave integral equation methods or ray tracing methods is awkward due to the large dimensions of the fuselage relative to the wavelengths of interest (as small as 6 mm) and the fact that the cabin consists of a complex collection of objects including people and seats. Prior investigations have mostly bypassed this problem by focussing on the path loss measured from the point at which power leaves the fuselage to the victim antenna. However, lossy materials within the cabin play an important role in determining the overall path loss. Therefore, it is desirable that any new analysis technique yield reasonable estimates in the presence of interior features, but at the same time should not require detailed information about the specific geometries or constitutive parameters of the media. Section 2 of this paper presents our solution to this problem, which involves a combination of techniques including microwave cavity theory for the interior part of the problem and the Uniform Geometrical Theory of Diffraction (UTD) for the exterior part of the problem. In Section 3, we demonstrate the effectiveness of the technique by comparison to measurements of various aircraft at the L1 (1575.42 MHz) frequency of the U.S. Global Positioning System (GPS).
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