Analysis of Methods to Improve the Axial Ratio of the Circularly Polarized Antenna Array

For improving the axial ratio characteristics of circularly polarized antenna array, the influence of array factor on the axial ratio by taking the cross-dipole as the array element has been analyzed in this paper. The relationship between the phase compensation of the array factor and the rotation direction of the element to achieve left-handed or right-handed circular polarization is also researched. In addition, the effects of first-order sequential rotation and second-order sequential rotation on the axial ratio characteristics are compared, and it is found that the second-order sequential rotation could only improve the axial ratio at the principal section of antenna pattern, and had no effect on reducing the maximum of axial ratio.