This paper describes an antenna technique which combines the dual-mode operation of a radiating square waveguide transmission line with the attachment of multiple ports to produce an antenna which can generate multiple, independent beams in space. The technique can be used to simultaneously transmit or receive signals through the beams with considerable isolation (>37 dB) between several of the ports. By this technique a single, traveling-wave-operated, linear array was designed to generate four unique beams in space. The beams consisted of two pairs of image beams which were produced by the use of an even coupling function design in the aperture. Measurements made of the array model at

-band showed good agreement with theory.