Study on Circularly Polarized Patch Antenna With Asymmetric Chiral Metamaterial

A circularly polarized (CP) patch antenna with a new chiral metamaterial structure was proposed. The proposed CP antenna is composed of a conventional linearly polarized patch antenna and a chiral metamaterial (CMM) board. For the CMM unit cell, the geometric parameters of the two pieces of copper films that are patterned on opposite sides of an FR-4 board are quite different. The function that a linear-polarization wave is converted into a circular polarization wave can be realized by the designed structure through simulation verification. When the CMM board is placed in the front of a conventional linear-polarized patch antenna, the antenna polarization mode can be changed to the circular polarized mode. The antenna performances have been investigated numerically and experimentally. Meanwhile, the new CMM structure could be applied to the field of circular-polarized antenna.