Slotted waveguide antenna with inclined stairs for effective side lobes suppression at 38 GHz

We propose and optimize the slotted waveguide antenna with inclined reflection canceling stair to enhance the design flexibility and suppress the side lobes rising from the offset variation. By employing the inclined slope on the stair, better phase and amplitude matching condition have been achieved which results in ultra-low reflection of -77 dB for single unit. In addition, there is a tradeoff between the minimal reflection condition and the most flexible design condition of the inclined slope. By setting h1 as 0.36 mm, below - 40-dB reflection can be obtained when the h2 is within the range of 0.1 to 0.8 mm. Thus, we can tune the h2 to adjust the waveguide space of next slot to realize uniform radiation without introducing any varying offset. (The design and analysis of full model is under progress, we would like to present the final side lobes suppression result in the final manuscript.)