Wideband E-/H-Plane Decoupling Design via Parasitic Structures Reuse for Low-Profile Dipoles

With the widespread adoption of massive multiple-input multiple-output (MIMO) technology, it has increasing demands for the array antenna systems, particularly in achieving effective decoupling under wideband operating conditions. To address this challenge, this paper presents a broadband decoupling design for low-profile wideband dipole antennas based on parasitic structure reusing. Two sets of parasitic elements, positioned on theE- plane and H-plane of the radiating antenna, simultaneously extend the impedance bandwidth to 4.6–8.3 GHz (56.6%) while maintaining a compact profile of 0.077λL, where λLdenotes the wavelength at the lowest operating frequency). When configured into a planar array, these two parasitic element sets are utilized to design theE-plane decoupling structure (EDCS) andH-plane decoupling structure (HDCS). By leveraging the inherent radiation characteristics of the parasitic elements, two distinct decoupling strategies are proposed: anE-plane approach based on broadband coupling path cancellation and anH-plane approach utilizing frequency-adaptive suppression. The fabricated 2×2 array demonstrates isolation exceeding 17 dB across the entire 56.6% operating bandwidth, with element isolation greater than 20 dB maintained over more than 41% of this range. Measured results validate the effectiveness of the proposed broadband decoupling methods.