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associated with the stored energy, and the other, a radiation field which moves out into
space at the speed of light.

At the antenna, the intensity of these fields is proportional to the amount of power delivered
to the antenna. A short distance from the antenna and beyond, only the radiation field
exists. This radiation field consists of an electric and magnetic component at right angles to
each other in space and varying together in intensity.

Figure 23-4 Magnetic and electric fields around an antenna
Figure 23-4 shows the manner in which the radiation field is propagated away from the
antenna. The electric and magnetic field components are represented here by separate
sets of flux lines, which are at right angles to each other and to the radial direction of
propagation.

The magnetic flux lines are shown as circular lines, having the axis of the antenna as their
axis, so that they appear in the illustration as dots and crosses. The electric flux lines are
closed or endless. The electric flux lines reverse direction, at precisely the places where the
magnetic flux lines reverse. Their density varies along the radial direction in the way that
the magnetic flux density varies.
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