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

Abstract

This study introduces a compact, wideband dual-polarized suspended patch antenna designed for LTE700/LTE850/CDMA850/GSM900 applications, with a focus on achieving high isolation. The antenna design has two suspended patches that are excited in orthogonal directions using a modified crossed-slot configuration. The modifications applied to the crossed-slot significantly enhance the −15 dB impedance bandwidth, resulting in improved port isolation between polarizations. Both theoretical analysis and experimental testing confirm these enhancements, revealing an impressive −15 dB impedance bandwidth of 37% (688-1000 MHz) and port isolation exceeding 35 dB in the operating band. The antenna exhibits symmetric and directional radiation patterns in principle planes, with half-power beamwidths ranging from 55.32º to 65.61º and 61.79º to 66.84º. Antenna gain show exhibits variation in the range of 7.3-8.4 dBi across the measured frequencies. The compact size of the antenna, measuring 380 × 380 × 43.6 mm³, makes it highly suitable for integration into commercially deployed base stations. Throughout the paper, we provide a detailed presentation of the antenna's geometry, feeding mechanism, parametric studies, and experimental results. The combined theoretical analysis and practical experimentation validate the success of the proposed antenna design, highlighting its potential for robust performance in a wide range of communication applications.

Keywords

• Dual-Polarization
• High Isolation
• Wideband
• Cross-slot Coupling
• Base Station Antenna

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