The Circular Polarization Diversity Antennas Achieved by a Fractal Defected Ground Structure

This paper proposes the circularly polarized (CP) antennas with a restored radiation pattern for the polarization diversity applications. The proposed CP antennas have dual polarizations, the left-handed circularly polarized (LHCP) antenna is designed for transmitting and the right-handed circularly polarized (RHCP) antenna is designed for receiving. The CP antenna operation and the radiation pattern restoration are realized by a fractal defected ground structure (FDGS). When achieving the radiation pattern restoration, the proposed CP antennas forward efficiencies are improved from 66.8% to 81% and the forward realized gains are improved from 2.56 dBi to 5.38 dBic, respectively.