A Low-Profile High Isolation Wideband Dual-Polarized Antenna for Sub-1 GHz Base Stations

In this paper, we present a low profile, wideband dual-polarized suspended patch antenna for LTE700/LTE850/CDMA850/GSM900 applications with high isolation. The proposed antenna element consists of two suspended patches excited orthogonally through modified cross-slot. It is theoretically and experimentally verified that this modification significantly widens −15 dB impedance bandwitdh and improves port isolation between polarizations. Experiments reveal in parallel with conducted simulations that the antenna is capable of exhibiting 37% −15 dB impedance bandwidth (688-1000 MHz) and more than 35 dB port isolation over operating frequency band. In principle planes, the antenna provides symmetric broadside radiation patterns at boresight with half-power beamwidths of 55.32º-65.61º and 61.79º-66.84º. Gain of the antenna varies within 7.3-8.4 dBi range at measured frequencies. The size of the antenna is 380 × 380 × 43.6 mm3 which makes it very suitable to integrate into commercially deployed base stations. Geometry, feeding mechanism, parametric studies and experimental results of the proposed antenna are presented throughout the paper.