High-Gain Wideband Metasurface Antenna With Low Profile

In this paper, a novel compact wideband and high-gain antenna based on metasurface is proposed. The antenna is an octagon with a side length of 32.3 mm and a height of 5.6 mm. The metasurface consists of two stacking layers, and both layers contain a 4×4 copper patch array. The antenna is excited by an aperture coupled structure made of an anomalous microstrip line and a narrow slot etched in the ground plane. Genetic algorithm (GA) is adopted to optimize all the parameters and obtain the valid performance of the metasurface antenna. Moreover, the antenna is modified by introducing nonuniform patch. Modification leads to varying degrees gain enhancement, and the peak is approximately 1.5 dB at 6.1GHz. The impedance bandwidth of the proposed antenna is 54.9%, ranging from 4.48-7.87 GHz. A prototype of the antenna is fabricated, and the measured results verify the design.