Open-Stopband Effect Suppression in Planar Leaky-Wave Antennas With 3-D Beam Scanning

This letter presents a six-port sector planar leaky-wave antenna (LWA) for 3-D beam scanning. The antenna comprises six identical surface wave launchers (SWLs) arranged in a fan-shaped array, a periodic metal strip structure, and an electromagnetic band gap (EBG) structure. Each SWL consists of a transition for microstrip to H-plane dielectric horn, launching a quasi-planar surface wave. A genetic algorithm optimizes the metal strip geometry to mitigate the open stopband (OSB) effect and achieve broadside radiation. A mushroom-type EBG structure further isolates the metal strips, minimizing unwanted surface wave coupling. Full-wave simulations and experimental validation confirm the antenna's performance. Within the 9–13 GHz band, the antenna achieves continuous beam scanning from −50° to +60°. By switching the feeding ports and adjusting the frequency, the beam can cover a significant portion of the upper hemisphere.