A Plus/Minus 45 Degree Dual-Polarized Base-Station Antenna With Enhanced Cross-Polarization Discrimination via Addition of Four Parasitic Elements Placed in a Square Contour

A novel method of enhancing cross-polarization discrimination (XPD) of a ±45° dual-polarized base-station antenna, by addition of four parasitic elements placed in a square contour, is presented. First, it was established that high XPD at the broadside can be obtained by addition of four parasitic elements around a simple ±45° dual-polarized basestation antenna. Second, we investigated the principle of wide beamwidth high XPD after studying magnitude currents on parasitic element, spacing between parasitic elements and length of parasitic elements. Finally, a ±45° dual-polarized base-station antenna was designed, fabricated and measured. Measurement results are in good agreement with the results of simulation in terms of radiation pattern, gain, and Voltage Standing Wave Ratio (VSWR). In particular, the enhanced XPD is more than 20 dB at the boresight and more than 10 dB within ±60° of the main lobe at the horizontal plane.