Miniaturized wideband metasurface antenna loaded with H-slot based on characteristic mode analysis

An H-slot loaded metasurface (MTS) structure has been developed for the purpose of constructing a miniaturized wideband metasurface antenna (MTSA). The MTS is composed of an array of 3 x 3 rectangular small metal patches, each of which is loaded with an H-slot. The inclusion of the H-slot significantly lengthens the current path on the small metal patch, resulting in a small antenna size. Since the direction of the effective total current does not change, the radiation performance of the antenna is almost unaffected. To excite the MTS resonance and generate a stable radiation pattern while decreasing the backward radiation, an L-probe with an intact ground is employed. Characteristic mode analysis (CMA) is applied to reveal the miniaturization mechanism of the MTS and guide modal excitation. The prototype is fabricated and measured within a compact radiation aperture size of 0.35 lambda 0 x 0.29 lambda 0 (lambda 0 is the free-space wavelength at the center operating frequency). The measured -10 dB impedance bandwidth is 20.16% (5.22-6.39 GHz), with a peak gain of 6.28 dBi and a front-to-back ratio is larger than 20 dB.