Efficient high gain circularly polarized microstrip antenna using asymetrical RIS surface

In this paper an efficient high gain circularly polarized antenna is proposed. A circularly polarized metal plated antenna is designed and an asymmetrical reactive impedance surface (RIS) is fabricated on a FR4 superstrate and placed above the antenna to increase the 3 dB axial ratio bandwidth. The antenna provides S₁₁ less than -20 dB and 3 dB axial ratio bandwidth over 5.699-5.912 GHz. The antenna offers 9.9 dBi gain, more than 90 % antenna efficiency and more than 20 dB F/B lobe ratio. Side lobe level is <;-20 dB and cross polarization is <; -15 dB. The antenna is fabricated and tested. The measured results agree with simulation results. The overall antenna dimensions are 60 mm × 60 mm × 4.6 mm.