Design of Dual Cross Dipole Antennas with Dual Frequencies and Dual Circularly-polarized

An integrated antennas are presented with dual frequencies and dual circularly-polarized (CP) in a common aperture. The proposed integrated antennas are consisted of dual crossed dipole antennas (CDA) with stacked structure, which used 90 degrees self-phase shifting structures in both CDAs for CP wave achieving by adjusting the proportion of the orthogonal arm lengths for 90 degrees phase difference forming. The upper CDA covers. 4.7% relative bandwidth from 1.55 GHz to 1.625 GHz with VSWR less than 2 and axial ration (AR) less than 3dB of left-hand CP (LHCP) and the nether CDA covers 3.4% relative bandwidth of 2.44 similar to 2.525 GHz for right-hand CP (RHCP).