Estimation of electromagnetic energy coupling to a wire residing inside a transport aircraft due to external radiating sources

An analytical method is presented to estimate EM energy coupled to a wire residing in the fuselage of an aircraft. A fuselage with a wire inside is modeled by a metallic rectangular cavity with a wiring inside and rectangular windows on its side walls. Using the equivalence principles and the rectangular cavity Green's functions, the EM fields inside the cavity due to the equivalent current sources on windows and wires are determined. By matching the tangential magnetic fields across the apertures and equating the total tangential electric field over the cylindrical surface of wires to zero, coupled integro-differential equations are obtained. The integro-differential equations in conjunction with the Method of Moments (MoM) are then solved for the unknown magnetic and electric current amplitudes. One of the advantages of the present approach is that it gives an accurate and efficient analytical model for the EM coupling studies which is computationally less intensive compared to other numerical methods. Numerical data on EM energy coupled to a cylindrical wire of various lengths and oriented along the two principle axes of rectangular cavity is presented. From the numerical data it is concluded that a cylindrical wire of length n/spl lambda//4 where n is an odd integer, would pick up maximum energy.