Mutual Coupling Reduction in 5G MIMO Antenna Using Dielectric Bridge and Superstrate

A dielectric bridge and superstrate are combined to reduce the mutual coupling between 4- and 8-element ME-Dipole antenna at the millimeter-wave (MMW) frequency range of 52-66 GHz (15.2% bandwidth). The dielectric bridge consists of a carefully inserted metallic plate inside a high dielectric substrate material. This combination is inserted on top of 15-row vias between the 4 and 8 antenna elements. When the superstrate is placed at 2.5 mm (0.5 lambda) (lambda is the free-space wavelength at the center frequency of 62 GHz) above the 4- and 8-element antenna, a maximum mutual coupling of 70 dB and 55 dB is achieved within the 4-element and 8-antenna ME Dipole antenna, respectively, in the H-plane. The edge-to-edge separation between the elements is 0.62 mm (0.12 lambda). The radiation pattern, S-parameters, and surface current of the reference and proposed antenna are compared to validate the proposed technique.