Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>
The wave impedance is everywhere 377 ohms, independent of whether
you are in the reactive near field or radiating far field. All that
impedance tells you is the relative strength of the E and H fields
of a "propagating" EM wave. If I set up a nifty magnetic probe and
an electric probe in the same location with all manner of waves
rushing by, the V/m should be 377 (more properly 120 pi) times the
A/m at that location.
In the reactive near field, this isn't necessarily the case (or
maybe it is.. I'll have to think about it), because you can have
fields that aren't radiating. Consider the field inside a charged
capacitor. The V/m may be very high, but since it's DC, the A/m is zero.
just to reiterate, there's no "sudden boundary" between near and far
fields. It's an arbitrary distinction. (sort of like skin depth)