Corrugations for suppressing undesired wave propagation in the transverse direction in a 45° linearly polarized 76 GHz parallel-plate waveguide two-dimensional slot-array

A novel mechanism based on corrugations is proposed to control undesired oblique wave propagation inside a parallel plate waveguide existing in the presence of 45° polarized radiating slots. The improvement in the near-field aperture distribution is demonstrated experimentally by aperture field measurement in a new slot array antenna incorporating these corrugations. Only marginal directivity improvement is observed and the measured gain is lower than in the original antenna (without corrugations) due to larger dissipative loss in the structure. However, it is argued that the proposed corrugated structure has the potential to improve the overall 2D slot array antenna performance after further optimization.