Wideband slot antenna array with gain stability based on metasurface

A broadband slot antenna array based on metasurface with gain stability is proposed for the 5 GHz wireless local area network (WLAN) band in this paper. Firstly, multi-mode resonant theory is used to widen the bandwidth of the slot antenna. Then, a non-uniform rhombic metasurface is placed above the slot antenna to expand the bandwidth of the antenna further while increasing the gain. Finally, nine rectangular patches are placed at the non-uniform rhombic metasurface. And the current in the high-frequency is amplified which leads to the maximum gain variation of only 1.7 dBi across the entire operating frequency range (4.7-7.7 GHz). To verify the design, a 2 x 2 antenna array is fabricated. The antenna array achieved a bandwidth of 47.6% (4.8-7.8 GHz) and a maximum gain of 15.2 dBi within the operating band. The 1 dBi gain bandwidth is 2.1 GHz (4.7-6.8 GHz).