Abstract:Combining the advantages of Wilkinson power divider, T-junction power splitter and sequential-rotation feed method, a novel low-profile broadband circularly polarized 2×2 antenna array is designed based on the dual-fed dual-polarized microstrip antenna. Radiation patch and feed network are integrated on the same substrate to improve the usage efficiency of the substrate, thus low-profile and broadband are obtained. Four elements are rotated 90° in turn. One-to-four T-junction power splitter provides the elements with balanced signals of equal magnitude and an incremental 90° phase. An antenna prototype is fabricated after simulation in Ansoft's HFSS. Good agreement is found between measurement and simulation. Experimental results show that the array has a 2-VSWR bandwidth of 27.78%, and a 3-dB axial ratio bandwidth of 52%. The maximum gain is 14.19 dB.