A Circularly-Polarized Three-Element Yagi-Uda Antenna Based on Element Rotation Coupling

A circularly-polarized (CP) three-element Yagi-Uda antenna based on the element rotation coupling is presented in this paper. The antenna consists of the director, reflector and dipole. The reflector has a rotation angle with the dipole and the director has another rotation angle with the dipole. When the dipole is coupled with the director and reflector, the two rotation angles will generate the phase difference of 90 degrees and equal amplitude for E-theta and E-phi in the y-axis far field and the Yagi antenna forms the CP radiation. The simulated radiation patterns verify the CP radiation characteristics of the proposed antenna. The proposed Yagi antenna has a different operating scheme from the traditional CP Yagi antenna. Due to these advantages of simple structure, high gain, good CP performance and low cost, the proposed CP Yagi antenna may be an important candidate for the wireless communication systems.