Self-Decoupled MIMO Antenna Realized by Adjusting the Feeding Positions

This paper proposes a novel decoupling technique achieved by adjusting the position of feeding probes of antennas. Two inherent radiation modes (patch mode and monopole mode), with different patterns and polarizations, are simultaneously excited by the same feeding probe. High isolation is realized based on manipulating the relationship of two-mode couplings by moving the feeding positions. Since the two radiation modes are generated by the same antenna element, the proposed MIMO antenna features a simple structure and compact size. For verification, a two-element array with center-to-center spacing of 0.404 λ0 (λ0 is the wavelength in the air) is prototyped and characterized. Simulation and experimental results show that the proposed novel technique can offer higher port isolation (>18.1 dB), increased efficiency (>70%), and a lower envelope correlation coefficient (ECC < 0.1) in the operating frequency band (11.61–12.49 GHz).