A Waveguide Slot Array Antenna With Reflection-Canceling Stairs for Sidelobes Suppression at 38 GHz

This paper presents a simulation and experimental study of a $10\times10$ alternating phase-fed single-layer waveguide slot array antenna with reflection-canceling stairs (RCSs) at 38 GHz. The aim of the study was to improve the aperture efficiency of the antenna. Two optimization methods were employed: 1) RCSs for each slot were proposed and optimized for height and position to minimize reflection, and 2) the broad wall width and slot offset were optimized to suppress grating lobes. A design procedure for the feed part was also presented. The characterization of the proposed antenna was found to be in good agreement with simulation results, with a measured S11 of less than −20 dB and a gain of more than 27.71 dBi at 38 GHz (corresponding to an aperture efficiency of 85.6%). The results of this study demonstrate the feasibility of using the proposed antenna in millimeter-wave communication systems.