Multibeam Antennas Based on Spoof Surface Plasmon Polaritons Mode Coupling

Wireless link has need of an omnidirectional antenna like dipole, but with higher gains. Of course, there is no way of achieving both of them simultaneously. To solve this contradiction, we propose to design multibeam antennas, which divide the radiation pattern of omnidirectional antennas into several beams. The antenna, based on spoof surface plasmon polaritons (SSPPs) mode coupling, consists of a feed monopole and N double-side corrugated metallic strips circling around the feed. The fields of the feed are coupled into SSPP waves that propagate along the strips and radiate at the end, dividing the omnidirectional radiation pattern into several beams. Three X-band prototypes of multibeam antennas with different radiation characteristics were designed, fabricated, and measured. Both numerical simulations and experimental results verify that the antennas are efficient in generating multiple beams with high gain at the predesigned directions.