A novel broadband polarization diversity antenna using a cross-pair of folded dipoles

A ±45° polarization diversity antenna with wide bandwidth is presented in this letter. The antenna has a half-power beam width of 65° in the horizontal plane for use in wireless telecommunication base stations. Especially, a folded dipole antenna with a protruding part is used as a +45° polarization element and the another folded dipole with a concave part is used as a -45° polarization element. The protruding part and the concave part of dipoles make the two folded dipoles with the same height but not touching each other. With such a cross-pair of folded dipoles, a small polarization diversity antenna is constructed. The antenna was analyzed and optimized by the high frequency structure simulation software, and a good agreement was achieved between computation and experiments on the half-power beam width in the horizontal plane.