Wideband Low-Profile Antenna Based on Dual-layer Non-uniform Metasurface

A brand new dual-layer non-uniform wideband metasurface antenna is presented, which uses different sizes of metasurface patches. The dual-layer non-uniform structure makes the antenna have larger bandwidth, higher gain, and smaller radiating aperture compared to other similar antennas. This metantenna has a profile height of $0.07 \lambda_{0}$ and because of the non-uniform design, the minimum size of the metasurface patch is $0.03 \lambda_{0}{ }^{2}$ and the maximum size is $00.16 \lambda_{0}$. With a center frequency of 5.5 GHz and a relative bandwidth of $27.6 \%(s 11{\lt}-10 \mathrm{~dB})$ and $\mathbf{2 3 \%}$ ($\mathbf{s} 11{\lt}-15 \mathrm{~dB}$), it further extends the performance of the metasurface microstrip antenna with a radiation efficiency of $\mathbf{9 5 \%} \%-96.5 \%$ and a gain of $7.0-7.9 \mathrm{dBi}$ in the $4.75-6.25 \mathrm{GHz}$ range.