A Single-Layer Differentially-Fed Beamwidth-Enhanced Dual-Polarized Antenna With the Addition of U-Shaped Coupling Branches

A single-layer differentially-fed dual-polarized (DP) antenna is proposed with enhanced half-power beamwidth (HPBW). To widen the beamwidth of the H-plane without narrowing the beamwidth of the E-plane, U-shaped coupling branches are added to the modified patch antenna. By adjusting the coupling distance and the length of the coupling branch, the current amplitude and phase on the coupling branch are effectively controlled and the HPBW of the H-plane can be widened. Finally, the DP antenna is fabricated and measured to verify the principle. The measured results show that the HPBWs of the DP antenna are larger than 109° in two principal planes. Moreover, benefiting from the single-layer microstrip structure, the profile of the antenna is only
$0.041\lambda _{0}$
(at 3.1 GHz).