Control of Two-Dimensional Leaky-Wave Amplitude Tapering in PRS Antennas for Sidelobe Suppression

Two-dimensional (2-D) partially reflective surface (PRS) antennas have attracted considerable interest over the past twenty years owing to their simple architecture and high‐gain capability. Despite extensive efforts to enhance gain and bandwidth, the sidelobe suppression—a critical requirement in many high‐directivity applications—has received comparatively little attention. In this work, we introduce a systematic design methodology for controlling the leaky‐wave amplitude distribution across a 2-D PRS aperture to meet specified beam‐ shaping objectives, with particular emphasis on sidelobe reduction. First, we derive an explicit relationship between the PRS reflection coefficient and the attenuation constant (leakage ratio), which enables direct calculation of the local leaky‐field amplitude on the aperture. Next, by enforcing energy conservation within the planar cavity formed by the PRS and a metallic ground plane, we develop a 2-D power‐transmission framework— presented in both continuous and discrete formulations—that relates local leakage power to the internal guided‐wave power distribution. This framework permits precise tailoring of the aperture amplitude profile and, consequently, the far-field radiation pattern. To validate the proposed approach, four PRS antennas incorporating phase‐correcting surfaces were designed, each exhibiting a prescribed amplitude taper. Measured and simulated results demonstrate excellent agreements and confirm predicted sidelobe suppression, thereby validating the efficacy of the method.