ABSTRACT
In many cases, the ElectroMagnetic environment externally incident or externally coupling to a system enclosure is quite tractable deterministically. It is also probably noteworthy that the exact opposite of applicabilities pertains where there are an uncountably infinite number of modes: the case in point is that of an aperture backed by a semi-infinite region of free space. Clearly, it is absurd to suggest that an aperture cannot transfer power from the illuminated side of an infinite conducting plane to the dark side until some energy has already entered the dark side. The eigenmode-coupling perception tends to be easier to visualize when the enclosure is not greatly larger than a wavelength, while the power-capture approach applies more obviously to just the opposite circumstance.
