<inline-formula><tex-math notation="LaTeX">$\text{M}^2\text{I}$</tex-math></inline-formula>: Channel Modeling for Metamaterial-Enhanced Magnetic Induction Communications

Abstract

Magnetic Induction (MI) communication technique has shown great potentials in complex and RF-challenging environments, such as underground and underwater, due to its advantage over EM wave-based techniques in penetrating lossy medium. However, the transmission distance of MI techniques is limited since magnetic field attenuates very fast in the near field. To this end, this paper proposes Metamaterial-enhanced Magnetic Induction (M 2 I) communication mechanism, where a MI coil antenna is enclosed by a metamaterial shell that can enhance the magnetic fields around the MI transceivers. As a result, the M 2 I communication system can achieve tens of meters communication range by using pocket-sized antennas. In this paper, an analytical channel model is developed to explore the fundamentals of the M 2 I mechanism, in the aspects of communication range and channel capacity, and the susceptibility to various hostile and complex environments. The theoretical model is validated through the finite element simulation software, Comsol Multiphysics. Proof-of-concept experiments are also conducted to validate the feasibility of M 2 I. Index TermsMetamaterial-enhanced Magnetic Induction, Wireless Communications, RF-challenging Environments.I. Introduction Despite the presence of wireless connectivity in most terrestrial scenarios, there are still many hostile and complex environments that cannot be covered by existing wireless communication techniques, including underground, underwater, oil reservoirs, groundwater aquifers, nuclear plants, pipelines, tunnels, and concrete buildings. Wireless networks in such environments can enable important applications in environmental, industrial, homeland security, and military fields, such as monitoring and maintenance of groundwater and/or oil reservoirs [1], or damage assessment and mitigation in nuclear plants [2], among others. However, the harsh wireless channels prevent the direct usage of conventional electromagnetic (EM) wave-based techniques due to the high material absorption when penetrating lossy media.Among potential solutions, the Magnetic Induction (MI) technique has shown great potentials in underground [3] and underwater [4] environments. In a MI communication system, the HF band magnetic field generated by a MI transmitter coil is utilized as the signal carrier [5]. Since most natural media have the same magnetic permeability as air, MI keeps the same performance in most materials. Even in lossy media like groundwater, the MI path loss caused by skin depth can be minimized since MI communication is realized within one wavelength from the transmitter [6]. In addition, MI does not suffer from the multipath fading problem in EM wave-based solutions [4]. However, MI systems depend on the magnetic field generated by the transceivers in the near field, which attenuates very fast. Consequently, the range of MI communication is very limited.To this end, we introduce metamaterials to MI communications, which can manipulate and enhance the magnetic fields transmitted and...