Low power beam switchable antenna arrangement

DETAILED DESCRIPTION FIG.
1 illustrates a low power, beam switchable, antenna arrangement in accordance with the present invention.
In the antenna arrangement of FIG.
1, a plurality of feedhorns 10.
sub.
1 -10.
sub.
N are positioned on a surface .
SIGMA.
with each feedhorn 10 being capable of launching a spherical wavefront 12 toward a parabolic reflector 14 having a predetermined aperture D.
For example, feedhorn 10.
sub.
1 is capable of launching a spherical wavefront 12.
sub.
1 which is reflected by reflector 14 into a planar wavefront 16.
sub.
1 at the aperture which propagates in a predetermined first direction as determined by the position of feedhorn 10.
sub.
1 on surface .
SIGMA.
.
Similarly, feedhorn 10.
sub.
N is capable of launching a spherical wavefront 12.
sub.
N which is reflected by reflector 14 into a planar wavefront 16.
sub.
N at the aperture which propagates in a predetermined second direction as determined by the position of feedhorn 10.
sub.
N on surface .
SIGMA.
.
Surface .
SIGMA.
, in accordance with the present antenna arrangement is located adjacent to the focal surface of reflector 14.
As was described hereinbefore with regard to the prior art, multibeam antennas are commonly constructed by placing different feedhorns or clusters of feedhorns at different locations on the focal plane of a parabolic reflector, each location corresponding to a different beam direction.
Thus the beam direction can be switched by switching between the various feedhorns by using any arrangement which is well known in the art such as, for example, waveguide or stripline switches for high speed switching or solenoid activated magnetic waveguide switching for slower speed switching.
In accordance with the present invention, the signals being launched in spherical wavefronts 12.
sub.
1 -12.
sub.
N are low power signals which have not been amplified to the proper high power level needed for transmission to a remotely located receiver for which the signal is destined.
Since the beam switching means need not handle high power level signals, such switching means, and more especially the beam forming means, can be simplified with lower power rated components