Base Station Antenna with Enhanced Cross Polarization Discrimination Performance by Using Horizontal Meandered Dipoles and Vertical Parasitic Elements

Abstract

In this study the design and implementation of a +/- 45 degrees dual polarized base station antenna with improved cross-polarization discrimination (XPD) values are presented. In order to increase the cross polarization parasitic elements are added to antenna design which are formed by two orthogonal dipoles above ground plane. The overall antenna and radiator sizes are diminished by using meandered dipoles. The designed compact antenna has VSWR of 2:1 within 1.71-2.69 GHz frequency band which covers GSM 1800/3G/LTE bands. In the given bandwidth minimum gain of the designed antenna is 0 dBi within the beamwidth of 120 degrees (+/- 60 degrees) at azimuth plane (phi = 0 degrees). Minimum XPD value of 2 dB is achieved between 1.71-2.4 GHz for +/- 60 degrees beamwidth without parasitic elements where XPD values are improved to minimum 10 dB by using thick parasitic elements. The designed antenna is manufactured where return losses for both port 1 and port 2 are measured to be higher than 10 dB and the isolation between ports is more than 20 dB. In addition the measured peak gain values are varied between 3 dB and 7 dB in frequency range of 1.71 GHz-2.69 GHz. XPD values are measured better than almost 10 dB in the given frequency band.