Single-Layer Miniaturized Wideband Antenna Based on Stub-Loaded Metasurface

This paper proposes a single-layer miniaturized wideband antenna based on the stub-loaded metasurface (MS) structure. The stub is loaded at the edge of a square MS cell and inserted into the gap between two adjacent cells, enhancing the surface capacitance and reducing the resonance frequency. Consequently, the stub-loaded MS structure can provide the resonance frequency of the conventional square MS structure while having a smaller aperture. In this way, a miniaturized wideband MS antenna based on the stub-loaded MS structure is designed. It has a bandwidth of 41% (4.5−6.82 GHz) and a compact size of $0.38{\lambda }_0\times 0.38{\lambda }_0$ (where${\lambda }_0$ is the wavelength at the center frequency). Subsequently, based on this miniaturized MS antenna, the partial peripheral cells, which initially have little effect on radiation, are modified to obtain a sufficiently excited radiation aperture, resulting in a larger bandwidth of 47% (4.61−7.43 GHz) with a size of $0.4{\lambda }_0\times 0.4{\lambda }_0$. Compared with the conventional MS antenna, the proposed antenna is 70% smaller in size while having a larger bandwidth and a simple single-layer structure.