Theory of a traveling wave feed for a planar slot array antenna

A planar array of longitudinal radiating slots cut in broad walls of rectangular waveguides is fed by a traveling wave array of centered-inclined coupling slots cut in the common broad walls of a feed waveguide and an array of orthogonal radiating waveguides. A theory is developed for the design of the resonant coupling slots using the scattering matrix representation. Numerical results computed for the radiation pattern, the tilt angles of coupling slots, and excitation phases of the radiating waveguides are presented for a uniformly excited array. It is shown that the use of resonant coupling slots simplifies the design process.