Multi-Mode Multi-Port (M3P) Metaloop Antenna for Near-Field Sensing and Communication using Characteristic Mode Analysis

An electrically-large multi-port metaloop antenna is proposed for multi-object near-field sensing with the advantage of uniform field distribution over a large area. The proposed metaloop antenna is excited by four ports of equal magnitude but different phases determined by characteristic mode analysis (CMA). Different from a conventional electrically-small single-port single-mode solid loop antenna, the proposed metaloop antenna is electrically-large with a perimeter of four wavelengths at 2.45 GHz and works with multiple modes. As a result, the operating area of the multi-port metaloop antenna is enhanced by 42.6% compared with that of the single-port design, characterized by 3-dB ripple of the magnitude of H-field normal to the loop plane. Potential applications of the proposed antennas include multi-object near-field sensing, fast massive faulty test in production line, wireless power transfer, underground communication and so on. Most importantly, the proposed method provides an alternate explanation of the working principle of electrically-large metaloop antennas from the perspective of resonant modes for further development of the antennas of its kind.