Planar waveguide array with nearly ideal radiation characteristics

A planar waveguide array with nearly ideal radiation characteristics was discussed. It was found that each array element consists of two waveguides, and the entire array consists of input section of period alpha , followed by a final section in which the period changes to alpha /2. The analysis suggested that this technique enables a rectangular element pattern to be realized, to a good approximation, by an array with realistic gaps between the adjacent waveguides.