A Center-Fed Triple-Mode Wideband Circularly Polarized Phased Array Using Characteristic-Mode Analysis

This letter proposes a novel center-fed (CF) triple-mode wideband circularly polarized (CP) array using characteristic-mode analysis. The proposed antenna can not only achieve the wideband CP property but also obtain more symmetrical patterns than the traditional off-center fed (OCF) patch antennas. The influence of the symmetry of the element pattern on the array scanning performance is analyzed further in this work. Two 36-element arrays consisting of the proposed CF elements and traditional chamfered OCF elements are fabricated and measured for comparison, respectively. The measurement results show that the proposed CF patch array can increase the peak gain almost 1.8 dB higher and greatly improve the axial ratio almost 3.5 dB better than the traditional OCF CP patch array when scanning to a large angle.