A Sub-6 GHz Antenna Array with Reduced Mutual Coupling Using Optimized Defected Ground Structure for 5G Testbeds

In this paper, a design of dual-element antenna array operating at 3.6 GHz frequency is introduced. The design challenge of the proposed antenna array was to minimize the mutual coupling effect between the patches when they are to be placed next to each other’s, optimally with a separation distance of half a wavelength. An optimized defected structure etched in the ground plane, is exploited to achieve this goal. Introducing such structures between the adjacent patches, is known to effectively reduce the propagation of surface currents and therefore, are forced to radiate rather than to leak to the neighboring elements, hence less mutual coupling between the adjacent antenna elements and better radiation efficiency. The array has been theoretically designed, simulated, practically fabricated and tested in both configurations with and without the suggested structure. The measurement results show a significant improvement of the performance over the standard design without the proposed structure.