An antenna is a
transducer
designed to
transmit
or
receive electromagnetic waves. In other words, antennas convert electromagnetic
waves into electrical currents and vice versa. Antennas are used in systems
such as radio
and television
broadcasting, point-to-point radio communication,
wireless
LAN, radar,
and
space exploration. Antennas usually work in air or
outer
space, but can also be operated under water or even through soil and rock
at certain frequencies for short distances.
Physically, an antenna is an arrangement of
conductors that generate a radiating
electromagnetic field in response to an applied alternating voltage and
the associated alternating
electric current, or can be placed in an electromagnetic field so that
the field will
induce an alternating current in the antenna and a voltage between its
terminals. Some antenna devices (parabolic
antenna,
Horn
Antenna) just adapt the free space to another type of antenna.
Marine Antenna Systems usually require sturdy
marine antenna mounts to attach the
antenna to the ship.