Modeling Considerations of Electromagnetic Penetration into Small Apertures

A study is made of numerical techniques used to simulate electromagnetic penetration through small apertures in cavities. The theory of these processes is reviewed and applied to a rectangular box model system. Agreement between theory and calculations are good for the modal amplitudes (usually within a factor of two) as long as the aperture is not too large to avoid re-emerging electromagnetic fields and care is taken to assure local symmetry in the electromagnetic structure of the aperture.