Design of Ultrathin Metasurface Lens for Gain Enhancement of Microstrip Patch Antenna

In this paper, gain enhancement of microwave radiator by using ultra thin compact metasurface lens is proposed. An ultrathin transmission type metasurface of thickness
$0.012\ \lambda$
with 3 dB transmission band of about 1 GHz with centre resonant frequency of 5.10 GHz is designed first. Next, a lens antenna is designed by placing the metasurface on the top of microstrip patch antenna radiator at an optimum focal length. The metasurface placed over microwave radiator causes convergence of radiated beam. The operating bandwidth of proposed lens antenna is 0.20 GHz from 5.00 GHz to 5.20 GHz. A measured broad side gain enhancement of about 3.75 dB is achieved at centre resonant frequency 5.10 GHz resulting in enhancement of aperture efficiency and directivity. The simulated and measured results are in good agreement.