X-band grating-loaded parallel-plate slot array antenna with low reflection

This letter proposes a design of an X-band multi-layered all-metallic slot array antenna with gratings loaded between parallel plates. Unlike the conventional structure with gratings loaded in parallel to the polarization direction to eliminate detrimental resonance in a 2×2-slot subarray, this design loads the gratings perpendicular to the polarization direction. Furthermore, short stubs along the polarization direction are proved necessary to facilitate the good performance of the subarray. The proposed 16×8-slot array demonstrates low-reflection, wide-band and high-efficiency characteristics in measurements.