A Wideband Differentially Driven Dual-Polarized Antenna by Using Integrated Six-Port Power Divider

A new method to design wideband differentially driven dual-polarized antenna with high common mode suppression and high port isolation is presented. The presented antenna can be equivalent as a combination of a six-port power divider and four crossed folded dipoles. The six-port power divider is composed of two orthogonal input ports and four equal magnitude output ports. The detailed analysis illustrates that the six-port power divider can have wide bandwidth and high isolation under odd mode excitation and high common mode suppression under even mode excitation. Therefore, based on the wideband and high even mode suppressed six-port power divider, a wideband differentially driven dual-polarized antenna is developed with high common mode suppression. To validate the design concept, the proposed antenna was designed, fabricated, and measured. The measured results prove that the antenna has a wide impedance bandwidth of 1.64-3.0 GHz (58.6%) for the return loss higher than 15 dB and isolation higher than 35.4 dB. In addition, very high common mode suppression is achieved for the measured common mode reflection coefficient higher than -0.87 dB over the entire bandwidth. With stable antenna gain and half power beamwidth, the develop antenna is suitable for base station applications.