A computational assessment of direct and indirect current injection techniques for missile EMC testing

The paper describes a computational study carried out within the British Aerospace Sowerby Research Centre of two ideas for injecting currents onto the surface of a missile for EMC-testing purposes: direct current injection (DCI), in which the missile is the centre conductor of a coaxial transmission line driven at one end, and indirect current injection (ICI), in which the missile is again the centre conductor of a coaxial line but excitation is provided by a driven wire running between the missile and the outer tube. The extent to which each of the two techniques is suitable as a substitute for direct illumination of the missile in free space is assessed on the basis of preliminary results.