Parallel plate lens antenna

DETAILED DESCRIPTION In accordance with the present invention, an antenna system is provided for producing a plurality of differently directed beams of electromagnetic energy, each one of such beams being associated with a corresponding one of a plurality of beam ports, each one of such beams being produced from a common array of antenna elements.
The antenna system includes a radio frequency energy lens assembly having a plurality of array ports coupled to the plurality of antenna elements.
The lens assembly includes a radio frequency lens having a plurality of lens ports disposed about peripheral portions thereof.
Each one of a first portion of such plurality of lens ports is coupled to a corresponding one of the antenna elements through a corresponding one of the array ports and each one of a second, opposing portion of the plurality of lens ports being coupled to a corresponding one of the beam ports.
Each one of the lens ports in one of the portions thereof includes a pair of tapered feeds.
A power divider/combiner is provided for each one of the pair of tapered feeds, such power divider/combiner having a pair of branch lines coupled to the pair of tapered feeds and a common line coupled to the one of the beam ports or array ports coupled to such lens port.
The electrical lengths between an input to the common line and the outputs of the pair of tapered feeds coupled to the branch lines of such power divider/combiner are equal.
With such arrangement, the antenna system is adapted to operate over a relatively wide band of frequencies.
In particular, such antenna system, and in particular the radio frequency lens thereof, has improved performance when operating with radio frequency energy having a wavelength .
lambda.
, in the range (d/0.
52)>.
lambda.
>(d/0.
64), where d is the separation between adjacent ones of the plurality of lens ports.