Theoretical and experimental evaluation of the electromagnetic radiation from apertures in shielded enclosure

The problem of the radiated emission from apertures in metallic enclosures has been theoretically and experimentally investigated. In particular, the tangential electric field in the aperture has been evaluated by two methods: the first is helpful during the design stage and the second during the prototype development stage of electronic equipment shielded by a metallic box. The first method is a rigorous approach and uses the equivalence principle that leads to an integral equation then solved by the method of moments. The second is an approximate technique. This technique is based on simple, cheap, and quick measurements of the normal components of the magnetic field across the aperture. Numerical simulation in good agreement with experimental results is shown.