Directional High Gain Antennas with Superstrate Coupled Configuration for Wifi Applications

A highly directional antenna with superstrate coupled configuration is used for the gain improvement for the planar microstrip patch antenna working at 2.4 GHz is proposed in this paper. Periodic metamaterial superstrate array with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2 \times 2$</tex>-dimension function as superstrate at a height of 0.128 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\lambda$</tex> above the microstrip patch antenna. It creates a cavity between the antenna and the superstrate. The peak broadside gain improvement of 3.8 dB is achieved. The parametric analysis of the unit cell is done and the shift in the resonant frequency is studied with respect to different parameters and its impact with the refractive index is also analyzed.