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The Zones

Suppose the source lives inside a region of maximum size $ d \ll \lambda$ where $ \lambda = 2\pi c/\omega$ . By that I mean that a sphere of radius $ d$ (about the origin) completely contains all charge-current distributions. Then we can define three zones of approximation:

  1. The near (static) zone $ d << r << \lambda$
  2. The intermediate (induction) zone $ d << r \sim \lambda$
  3. The far (radiation) zone $ d << \lambda << r$
The field has very different properties in these zones. We will briefly discuss each of them.


next up previous contents
Next: The Near Zone Up: Simple Radiating Systems Previous: Simple Radiating Systems   Contents
Robert G. Brown 2017-07-11