High-Efficiency Low Profile Full-Metal CTS array for SATCOM

This article presents the design and numerical investigation of a fully metallic low-profile antenna operating in the Ka-Band. The antenna is composed of two stacked circular parallel plate waveguides (PPWs), for beamforming and radiation, respectively. The system’s beamformer, positioned at the bottom of the structure, consists of a planar lens working in reflection, while the radiating part consists of a Continuous Transverse Stub (CTS) and is positioned on top. This latter PPW has corrugation on the bottom wall to support a slow wave, and slots etched on the upper wall to obtain radiation. The relative rotational movement between these two sections generates a phase gradient across the radiating aperture, resulting in a scan of the beam in the upper hemisphere. This approach ensures nearly frequency- and scan-independent active impedance and radiation efficiency, yielding broad band and consistent performance across all pointing directions. Furthermore, tapering efficiency is enhanced by appropriately adjusting the radiating slot width.