EMC PREDICTION MODEL OF A SINGLE WIRE TRANSMISSION-LINE CROSSING A CIRCULAR APERTURE IN A PLANAR SCREEN

The structure composed by a wire running above a ground plane and pass ing through an aperture in a semi-infinite metallic screen is analyzed from an electromagnetic point of view, We assume that the distance be tween the wire and the ground plane is sufficiently greater with respe ct to the aperture dimensions and that the latter are small in compari son with the free-space wavelength, A very accurate low frequency solu tion is obtained by representing the field quantities in a suitable sp ectral domain and by treating the wire current as a filament current, A transmission line model of the structure, based on the scattering pa rameter representation for both internal and external excitation, is d erived, Then, by use of such a model, analytical expressions for an in sertion loss and a signal-to-noise ratio (SNR) are obtained in order t o assess the electromagnetic compatibility of the structure.