Dual-mode stripline antenna feed performing multiple angularly separated beams in space

Claim 1

An antenna feed having first and second transmit/receive ports and a plurality of antenna element ports for connection to the elements of a linear antenna array to generate at least two angularly separated beams in space therefrom, comprising: a length of non-dispersive TEM transmission line having first and second generally parallel, laterally-spaced center conductors associated with a dielectric material and discretely connected to said first and second transmit/receive ports, respectively, the other ends of said center conductors being discretely load terminated; first means comprising a phasing device having in-phase and anti-phase ports and third and fourth ports connected to said transmission line first and second transmit/receive ports, respectively, said phasing device being operative to excite said center conductors in-phase to generate an even electric field mode within said transmission line during excitation of said in-phase port and to excite said center conductors in anti-phase relationship to generate an odd electric field mode within said transmission line during excitation of said anti-phase port; second means comprising a plurality of couplings, one for each of said antenna element ports, said couplings each including a quarter-wave conductor parallel and close coupled to one of said center conductors and a feed strip extending generally perpendicular from one end of each of said coupling strips to a corresponding antenna element port, said coupling strips being load terminated from their other ends.