Grating Sidelobe Suppression in Single-Layer Center-Feed Waveguide Antenna Array at 38 GHz

In this paper, we optimize the width of a slotted waveguide to minimize the distance between the adjacent diagonal slots for grating sidelobe suppression. By solving the tradeoff between the waveguide width and the guided wavelength. We find the waveguide with a width of 5-mm has optimal performance. Furthermore, by shrinking the waveguide width to 5 mm, we obtain a perfect single-peak radiation pattern in E-plane and an extremely high antenna efficiency (89.4%). Finally, the corresponding directive gain can be increased to 27.9 dBi.