A Shared-Aperture Luneburg Lens Multibeam Antenna Array With Large Frequency Ratio for 5G Communication Systems

This paper presents a novel design methodology for a shared-aperture multibeam Luneburg lens (LL) antenna array with large frequency ratio for 5G communication systems. This approach adopts a holistic perspective by structurally reusing the sub-6 GHz dipole arms, integrating multiple millimeter-wave (MMW) dipoles with the sub-6 GHz dipoles to share a common radiating aperture. The resulting shared-aperture antenna integrating 30 MMW dipoles and 7 sub-6 GHz dipoles is arranged along the equator of the LL to serve as the feed for the multibeam antenna array. Leveraging the frequency-invariant focusing characteristic of the LL, the proposed array achieves wide-angle beam scanning across the sub-6 GHz and MMW bands. Prototype fabrication and measurement were carried out to verify the proposed design,demonstrating a beam coverage range of ±72° with a peak gain of 16.7 dBi in the 2.4–4.3 GHz band, and a beam scanning range of ±78° with a peak gain of 29 dBi in the 21.5–40 GHz band. The proposed shared-aperture multibeam antenna offers a promising solution for reducing the size and cost of the 5G communication systems.