Fully Metallic Dual-Band-Multibeam Aperture-Shared Lens Antenna for N257 Millimeter-Wave and N79 Sub-6-GHz Applications

This article demonstrates a dual-band aperture-shared wide-angle multi-beam lens antenna for the N257 millimeter-wave (mmW) and N79 Sub-6-GHz applications. The key novel contributions of this article include: (1) A new antenna structure using a dual-band multi-port waveguide-based feeder array and a wideband lens beamformer is proposed. The parallel-plate waveguide (PPW) geodesic lens with precisely designed focal position is employed to support the beamforming at Sub-6-GHz (4.5-5.0 GHz) and mmW (26-30 GHz) bands simultaneously. (2) A method for the independent feeding paths of two frequency bands is developed, wherein the Electromagnetic Bandgap (EBG) structures with a passband in the Sub-6-GHz and a stopband in mmW are implemented. In the experimental verification, 11 mmW waveguides and 5 Sub-6-GHz waveguides are placed at the edge of the lens to obtain ±60° and ±50° beam scanning respectively, with the corresponding scan loss of 0.2 dB and 0.6 dB. In addition, the sidelobe levels are below −15 dB and −9.6 dB with the maximum gain of 25.2 dBi and 14.1 dBi at mmW band and Sub-6-GHz band respectively. This work provides a dielectric-free multi-beam antenna solution for multi-band aperture-shared applications such as 5G communication.