  We show experimentally that a continuous, linear, dielectric antenna in which
a superluminal polarization-current distribution accelerates can be used to
transmit a broadband signal that is reproduced in a comprehensible form at a
chosen target distance and angle. The requirement for this exact correspondence
between broadcast and received signals is that each moving point in the
polarization-current distribution approaches the target at the speed of light
at all times during its transit along the antenna. This results in a one-to-one
correspondence between the time at which each point on the moving polarization
current enters the antenna and the time at which {\it all} of the radiation
emitted by this particular point during its transit through the antenna arrives
simultaneously at the target. This has the effect of reproducing the desired
time dependence of the original broadcast signal. For other observer/detector
positions, the time dependence of the signal is scrambled, due to the
non-trivial relationship between emission (retarded) time and reception time.
This technique represents a contrast to conventional radio transmission
methods; in most examples of the latter, signals are broadcast with little or
no directivity, selectivity of reception being achieved through the use of
narrow frequency bands. In place of this, the current paper uses a spread of
frequencies to transmit information to a particular location; the signal is
weaker and has a scrambled time dependence elsewhere. We point out the possible
relevance of this mechanism to 5G neighbourhood networks. This work also
constitutes a ground-based astrophysics experiment that gives strong clues
towards the emission mechanism of pulsars.
