Millimeter-Wave Multibeam Antenna Based on Holographic Metasurface With High Aperture Efficiency and Low Sidelobe Level

In this communication, a circularly polarized multiport multibeam antenna based on low-profile holographic metasurface (HM) with high aperture efficiency and low sidelobe level (SLL) is presented. Three potential multibeam antenna solutions are introduced and their merits and drawbacks are compared. Among these, the proposed dual-layer co-modulation topology achieves high aperture efficiency through dual-layer aperture multiplexing, along with improved inter-port consistency. Moreover, to mitigate the mutual coupling between independent beams in conventional multibeam antennas, the multiport spacing is optimized to obtain low SLLs and low cross-polarization levels. As a validation of the proposed topology and modulation method, a dual-port dual-beam HM is fabricated and measured. This prototype achieves a maximum realized gain of 22.1 dBic at 26.2 GHz with an aperture efficiency of 23.4%, while the SLLs remain below -19 dB for dual-port. The proposed multibeam antenna features low-profile, low SLL, high efficiency, and self-duplex, which is a good candidate for millimeter-wave (mmW) wireless communication, imaging, and radar systems.