Low-Profile Broadband Metasurface Antenna Under Multimode Resonance

A broadband metasurface antenna is proposed in this letter. The antenna is based on a nonperiodic metasurface. The modal behavior of the metasurface and the slot is analyzed using characteristic modes analysis (CMA). Three desired modes of the metasurface are found. Furthermore, the slot acts not only as a feeding structure but also as a metasurface-loaded antenna. By combining the three modes of the metasurface and the modes of the slot, the wide bandwidth is achieved under multimode resonance. To verify the design, the proposed metasurface antenna is simulated, fabricated, and tested. The results show that the proposed metasurface antenna achieves a wide impedance bandwidth above 79% and a wide 3 dB realized gain bandwidth of 77%.