Metasurfaces Meet Characteristic Modes

This paper reviews the recent development of metasurface (MTS) antennas with the aid of characteristic mode analysis (CMA), focusing on the unique advantages and new explanations offered by CMA for insightful modeling, accelerated analysis, effective mode excitation, selective mode manipulation and efficient mode synthesis. Advantages of multi-mode MTS antennas are summarized from three different aspects, including antenna element, array and multi-port antenna system, featuring enhanced bandwidth, improved radiation patterns, higher port isolation, smaller footprint, clearer physical understanding and more. Future directions are also briefly introduced.