Toward Electromagnetic Near-Field Suppression and Enhancement with Janus Antennas

Description

The proliferation of 5G, IoT and other massive wireless networks is made possible in part through the use of a large number of antennas which often work in close proximity to one another. For example, in a multiple input multiple output (MIMO) antenna system, multiple antennas work together to increase the channel capacity and enable the rapid transfer of a large amount of data. However, the close-packing of antennas leads to significant mutual coupling (electromagnetic cross-talk among antennas), which degrades the communication capacity. Minimizing mutual coupling among closely-spaced antennas can enhance the performance of MIMO antenna systems and make them more compact. In another application scenario, many wireless power transfer (WPT) systems transmit power wirelessly among two or more antennas and/or resonators which are electrically close to each other. Here, maximizing the coupling between the transmit and receive antennas will improve the system’s power efficiency and eliminate unwanted power leakage. These important applications showcase the attractiveness in controlling the electromagnetic coupling of closely-spaced antennas and electromagnetic structures. Where the Huygens’ source and related antennas have contributed significantly to far-field directionality, the strongly related Janus source has been recently reported to achieve an analogous near-field directionality. However, an active Janus source is yet to be proposed, and its usage in practical applications remains largely unexplored. The proposed research project fills this research gap. We will investigate the electromagnetic near-fields of the ideal Janus source and clarify the nature of its near-field directionality. We will then proceed to design and demonstrate a Janus antenna – an antenna that implements an active Janus source. Finally, we will use our Janus antenna to demonstrate the direction-controlled suppression and enhancement of mutual coupling among closely-spaced antennas. Our preliminary simulation results have shown, in a 2D environment, the creation of an active Janus source and strong mutual coupling suppression for closely-spaced Janus sources. These results strongly indicate that similar achievements are possible in a 3D environment. The research team, consisting of experts in metasurface and antenna design and, notably, the inventor of the magneto-electric dipole, is strongly suited for the proposed project. We expect this project will lead to pioneering demonstrations of the Janus antenna and their usage in direction-controlled near-field coupling suppression and enhancement. These contributions represent exciting academic achievements and will open doors to strong potential applications in MIMO systems, antenna beamforming arrays and WPT systems.