Honeycomb-Shaped Holographic Metasurface Antennas Using Stepped-Impedance Distribution for Expandable Multibeam Applications

This letter introduces a novel approach to enhance the performance of a multibeam modular holographic metasurface (MTS) antenna by combining the stepped-impedance distribution (SID) with electromagnetic bandgap (EBG) structures. The utilization of SID is intended to mitigate undesired impedance deviations arising from multiple impedance modulations, thereby enhancing the gain of the MTS antenna. Furthermore, integrating additional EBG structures is beneficial for lower sidelobe levels (SLLs) by reducing the interference effects from other sources. For validation, an MTS antenna comprising three modules operating at 10 GHz, with target angles set at 0$^\circ$, 20$^\circ$, and 30$^\circ$, was designed. The measured results agree with simulated data, demonstrating a substantial improvement in gain values of 2.24 dBi, 1.59 dBi, and 4.7 dBi while maintaining the SLLs of −11.19 dB, −11.64 dB, and −12.17 dB across each respective target angle, compared with conventional averaging impedance method based on isotropic honeycomb elements.