A Novel Dual-Mode Decoupler Achieving Simultaneous E-/H-Plane Coupling Suppression for Diverse MIMO Antenna Configurations

This communication presents a novel dual-mode decoupler (DMD) that integrates orthogonal J-mode and M-mode within a single planar structure, enabling simultaneous suppression of E-plane and H-plane coupling in compact patch antenna arrays. Analytical modeling, based on a four-port impedance network, clarifies the operation mechanism, showing how mode-specific impedance loading achieves robust decoupling. Experimental results demonstrate the DMD’s versatility: J-mode or M-mode can be selectively employed for independent E-plane or H-plane decoupling, while synergistic operation supports dual-polarized MIMO, 2D 4 × 4 MIMO, and same-sense circularly-polarized (CP) MIMO designs. Simulations and measurements confirm the CP MIMO implementation achieves a 5.1 dBi peak gain and a 180 MHz axial ratio bandwidth (3.6% at 5 GHz). The DMD mitigates E-plane and/or H-plane coupling in dense arrangements, improving scalability and multi-polarization performance for wireless systems.